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Yamaha Banshee Q&A

August 28, 2011 by · 3 Comments 

Banshee Electrical FAQ

Everything you ever wanted to know (probably more) about Banshee electrical systems!  While the specifics listed are based on the Banshee’s electrical system, the principals remain the same and are similar for other simple 2-stroke motors (as always a service manual will provide you with specific testing values and is a sound investment.  I’ve tried to cover as many electrical issues as possible, from the most basic to the more complex, so some of you may want to skip ahead, and others are welcome to add anything that I’ve missed or have yet to learn.  There are many pictures so make sure to let the page load.

First off, here’s an illustration of a typical Banshee stock electrical system, later year models will have additional wiring for brake lights:

yamaha banshee electrical

Next, here are some electrical specifications for an ’87 and up Banshee:

Stator resistance:
Ignition coil should be 13.7-20.5 Ohms (red to green wire)
Pickup coil should be 94-140 Ohms (white/red to white/green wire)
Lighting coil should be 0.26-0.38 Ohms (black to yellow wire)

Coil resistance:
Primary coil should be 0.28-0.38 Ohms
Secondary coil should be 4,700-7,100 Ohms

Pickup coil gap: 0.015″-0.020″

Spark plug: NGK BR8ES

Park plug gap: 0.7-0.8mm (0.028-0.032″)

Finally, here is a link to some good basic explanations of how the electrical system functions in a car, many of the principles are the same:

http://auto.howstuffworks.com/ignition-system.htm

Q & A, The Basics

Q#1:Why is a functional electrical system important?
A#1:At worst, it flat won’t run.  Maybe worse, it’ll run like crap intermittently, often for no apparent reason or without any common symptoms.  However, learning a few basics will help you solve an electrical problem quicker and save you alot of grief.

Q#2:What are the parts of a Banshee electrical system?
A#2:I’m glad you asked.  The basic Banshee electrical system consists of a stator, stator plate, flywheel, woodruff key on the crankshaft where the flywheel mounts, pickup coil, CDI, coil, spark plug wires, spark plugs, voltage regulator, taillight, headlights, key switch, a handlebar-mounted light & kill switch, and a wiring harness.  Most Banshees (as equipped from the factory) also have TORS (Throttle Override System), and later models (approximately 2003 and later) have brake light systems.

Q#3:What is a “stator”?
A#3:A Stator is at the heart of the electrical system, whose job it is to provide electricity to the rest of the electrical system.  On a Banshee, the stator is found on the left-hand side of the bottom end of the motor, by removing the stator cover (black plastic on a stock motor) and flywheel.  The stator itself is a doughnut-shaped device made up of several poles on the perimeter wrapped with copper wire, and has four wires going to the wiring harness.  It is held onto the aluminum stator plate with three screws, and subsequently the stator plate is secured to the engine’s bottom end with three bolts.  Here’s a pic of  a stock stator and plate (the stator poles are coated with red liquid electrical tape), after removing the flywheel:

yamaha banshee

Q#4:How does the stator work?
A#4:The stator produces electricity by converting the kinetic energy of the rotating flywheel into electrical energy.  In English, this means that as the motor spins, the flywheel connected to the crankshaft turns the flywheel around the stator and produces electricity.  Similar to an alternator in a car (or a generator/magneto in other applications), the stator and spinning flywheel produce current for the ignition and lighting system.  I should note that the ignition and lighting parts of the stator are separate, while both perform the same job of producing electricity, the ignition coil of the stator is a different part of the stator itself than the lighting coil.

Q#5:What’s a “stator plate”?
A#5:The stator plate is a cast (stock) or machined (aftermarket) aluminum plate that the stator and pickup coil bolt onto, and is then bolted to the bottom end of the motor.  Here’s a pic of a stock stator, stator plate, and pickup coil:

yamaha banshee

Q#6:What does the stator plate do?
A#6:The stator plate holds the stator in place on the bottom end of the motor centered on the crankshaft so the flywheel can spin around the stator, and also has a mount for the pickup coil.  Aftermarket stator plates either provide slotted mounting holes where the stator plate bolts to the motor, or have adjustable pickup coil mounts, allowing the ignition timing to be advanced or retarded (see Q#54-56).  Here’s a pic of an adjustable stator plate next to a stock one:

yamaha banshee stator plate

Q#7:So what is a “flywheel”?
A#7:The flywheel spins around the stator to produce electricity, and also tells the CDI where the pistons are relative to TDC (top dead center).  Also found on left-hand side of the bottom end of the motor, the flywheel fits over the stator.  The flywheel is mounted to the tapered end of the crankshaft with a 19mm nut and lock washer, and is “indexed” to the crankshaft with a woodruff key (see Q#9).  Located on the perimeter of the flywheel are two raised, rectangular tabs that the pickup coil uses to signal the CDI when to fire the spark plugs.  The inside of the flywheel is magnetic, which in conjunction with the stator creates a magnetic field and then electricity.  Here’s a pic of a factory  flywheel:

yamaha banshee flywheel

Q#8:How does the flywheel work?
A#8:Together with the stator, the spinning flywheel creates current for the ignition and lighting circuits.  Together with the pickup coil, the flywheel tells the pickup coil where the pistons are so the CDI can fire the spark plugs.  As the flywheel rotates, the pickup coil senses the location of the tabs on the outside of the flywheel, and sends a pulse to the CDI.  Another function of the flywheel is to store inertial energy; by spinning on the crankshaft the flywheel’s weight can affect how fast engine RPM rises and falls.  A relatively heavy stock flywheel will keep the crankshaft spinning longer than a lightened flywheel so when you let off the throttle and then hit it again there is less “lag” between the time that the motor hits it’s “power band” (or peak horsepower RPM) and the RPM that it was spinning when you let off the throttle…the downside of a heavy flywheel is that from a very low RPM it takes longer to hit the power band.  Conversely, a lighter than stock flywheel has less rotating mass so the engine can accelerate quicker from low RPM to high RPM, but when you let off the throttle it will also decelerate quicker, which means getting back into the power band can take longer.  Opinions vary, but in general you will see drag racers using lighter flywheels where every tenth of a second counts in quick acceleration, and woods racers using stock flywheels (or even adding flywheel weights in many dirt bike applications) to maintain RPM and minimize clutching, thereby reducing rider fatigue.  Here’s a pic of a lightened flywheel, you can see where material has been removed from the perimeter of the flywheel but the tabs were not touched:

yamaha banshee flywheel

Q#9:What the hell is a “woodruff key”?
A#9:A woodruff key is a shaft key that’s shaped like a half-circle when viewed from the side.  It is made to fit into a half-circle slot machined into a shaft, in this application the tapered end of the crankshaft.  The inside of the flywheel has a rectangular slot or “keyway” that fits over the woodruff key as it sits in the crankshaft’s slot.  Here’s a pic of a woodruff key, and the crankshaft keyway without the woodruff key installed:

yamaha banshee woodruff key

Q#10:What does the woodruff key do?
A#10:The woodruff key sets the flywheel’s position onto the crankshaft.  This is also known as “indexing” the flywheel to the crankshaft, or making sure that that the flywheel stays in the right position relative to the crankshaft.  It’s important to

yamaha banshee woodruff key

note that the taper of the flywheel and the torque on the flywheel nut is what keeps the flywheel mounted securely to the crankshaft.  The woodruff key itself does not bear any rotational or axial load, it’s only purpose is to index the flywheel to the crankshaft when the flywheel is mounted.  That said, aftermarket offset woodruff keys (often called “degree keys”) are available that change the flywheel’s position relative to the crankshaft, thereby altering the ignition timing (see Q#54 & 55).  A PROPERLY installed degree key is no less reliable than a stock woodruff key (you might need to rejet!), since it’s only function is to locate the flywheel on the crankshaft, so don’t be afraid of the thinner offset of the degree key, just make sure the offset is in the correct direction and the flywheel is installed correctly (see Q#48).  Here’s a pic of a degree key installed on a crank:

yamaha banshee woodruff key

Q#11:What is a “pickup coil”?
A#11:A pickup coil is a small black box mounted to the stator plate.  It has two slotted mounts where two small Phillips-head screws secure it to the stator plate, and has two wires leading to the wiring harness.  The side of the pickup coil facing the flywheel has a small round metal nub on it.

Q#12:What does the pickup coil do?
A#12:The pickup coil senses the two rectangular tabs on the flywheel as it spins, and sends a pulse to the CDI.  The CDI relies on this pulse to know where the pistons are at relative to TDC, and also at what RPM the motor is turning at by how many pulses it receives over a given time period.  The pickup coil needs to be close enough to the flywheel tabs to sense them, but not so close that the tabs hit the pickup coil.

Q#13:What’s a “CDI”?
A#13:The CDI, or Capacitor Discharge Ignition, is the “brains” of the ignition system.  It takes the electricity produced by the stator’s ignition circuit, the input of the pickup coil, and tells the coil when to fire the spark plugs.  The CDI is a rectangular black box located under the center of the rear fenders, just forward of the grab bar and seat latch.  The CDI is mounted with a small flat rubberized metal bracket with two 12mm bolts, and has two short four-wire connectors (later models have a four-wire and a five-wire connector).  There are no moving parts in the CDI, so it is a “solid-state” device, meaning that it is completely electronic.

Q#14:How does the CDI work?
A#14:The CDI receives the electricity provided by the stator’s ignition circuit, and when it receives a signal from the pickup coil telling it the engine’s RPM and the piston’s location relative to TDC, the CDI then sends a current signal to the coil, which in turn fires the spark plugs.  The electronics within the CDI will fire the spark plugs before (advanced timing) or after (retarded timing) the pistons reach TDC depending on engine RPM, to provide the most efficient spark and a clean combustion process.  Banshee CDI’s have NO rev limiter, as some 2-strokes and most 4-stroke CDI’s have, that will cut out the ignition or otherwise prevent the motor from exceeding a preset RPM.  The TORS system, which is independent of the CDI (see Q#20), performs a similar job by limiting spark if the emergency brake is “on” or the carburetor slides are open when the throttle is closed, but the CDI itself does not limit RPM.  Don’t be fooled!  The only rev limiter on a Banshee is the stock pipes, the CDI would happily turn 20k RPM, if your motor stayed together…

Q#15:What is the “coil”?
A#15:The coil fires the spark plugs when it receives a current signal from the CDI.  On a Banshee the coil is bolted to the frame just forward of the right cylinder, has two male spade terminals for an orange and black wire from the wiring harness, and has two spark plug wires with caps.  It isn’t a slinky so don’t look for one on your Banshee.  Here’s a pic of a factory coil:

yamaha banshee coil

Q#16:How does the coil work?
A#16:The coil receives a current signal from the CDI, steps up the voltage, and fires both spark plugs at the same time.  The fact that both plugs fire at the same time makes no difference on a 2-stroke motor like a Banshee, where the pistons are 180 degrees apart, and can be useful in locating potential problems with a single cylinder.  Since one piston is on its compression stroke while the other is on its intake stroke, having both spark plugs fire at once is not harmful, and from a manufacturing viewpoint makes only a single coil necessary instead of independent coils for each cylinder.  The coil works by using the electromagnetic field that is pumped into it on the primary winding side, and when power is taken away, the field “collapses” and the secondary winding(s) “collect” the power and jump it to the required voltage.

Q#17:What are “spark plug wires” (or leads) and what do they do?
A#17:The plug wires are high-tension wires that carry a high voltage electrical signal from the coil to the spark plugs.  They are mounted at the coil with a flimsy plastic retainer that tends to break easily if you screw with it.  At the spark plug end they have a rubber spark plug boot with a built-in resistor, seen on the wire just before the spark plug cap.  Here’s a pic of a spark plug cap removed from the spark plug wire, showing the resistor parts inside:

yamaha banshee spark plug wires

Q#18:What are spark plugs and what are they for?
A#18:The spark plugs thread into the top center of the cylinder head in a 14mm hole, have a white porcelain top half, a threaded silver metal bottom half with a small metal ground strap on the center pointing to a ceramic center electrode with a small metal tip.  They receive the high voltage electrical signal from the coil and produce a spark (imagine that) to ignite the intake charge and initiate the combustion process.  More than anyone ever wanted to hear about spark plugs, but they are a vital part of the ignition system.  For more information about how to read spark plugs, check out the Jetting FAQ.  Otherwise just be content knowing that they ought to spark when you kick it over.

Q#19:What is a “voltage regulator” and what does it do?
A#19:The voltage regulator is a small, square, silver box with a single (usually blue) wire coming out of it leading to the wiring harness.  It is mounted just to the right-hand side of the CDI under the rear fender, and typically one of the 12mm mounting bolts has an eyelet terminal with a black ground wire going to the wiring harness.  The voltage regulator is NOT part of the ignition system, but part of the lighting system.  Its purpose is to regulate voltage (you don’t say) to the lights, preventing them from blowing because of too much voltage.  The voltage regulator on a Banshee limits voltage to 12 volts no matter what RPM the motor is at, since the higher the RPM the more voltage the stator will produce, the voltage regulator prevents the voltage at the light bulbs (and the wiring harness leading to the light bulbs) from exceeding 12 volts.  As you’ve no doubt witnessed, at idle or low RPM, the stator’s ignition coil does not produce much voltage, as the lights are real dim.  When you wind it out they light up pretty well, but if it wasn’t for the voltage regulator they would burn out quickly from the higher voltage.

Q#20:What is the TORS?
A#20:TORS is the Throttle Override System found on stock Banshees.  It consists of the large boxy carb tops, a switch on the thumb throttle housing, a switch on the parking brake perch, and a control box mounted to the frame rail above the left cylinder.  The function of the TORS is to limit engine RPM if the parking brake is engaged, or if the throttle is released and the carb slides don’t.  If the switch at the parking brake senses that the parking brake is engaged, it tells the carb tops not to lift the carb slides.  Similarly, if the switch at the thumb throttle senses that the thumb throttle has been released, the carb tops won’t lift the carb slides.  The problem with the system is that often the switch on the parking brake perch will fail to sense that the parking brake is not engaged, and will then limit RPM (the motor won’t rev past idle); adjusting the switch is the first solution, eliminating the TORS is a better one.  Other drawbacks to the TORS is that the carb tops are huge and makes jetting more time consuming, the entire system is one more thing that can (and usually will) fail, and the system adds unnecessary weight.  Eliminating the TORS is well worth the effort.

Q#21:How do I eliminate the TORS?
A#21:Several companies sell TORS elimination kits (Toomey, Vito’s, etc.) that include aftermarket Mikuni carb tops, throttle cable, and an idle screw kit.  The throttle cable and carb tops are a simple matter of removing the old and installing the new.  The idle screw kit requires removing the carbs, drilling a hole (on the left side of the left carb and on the right side of the right carb), tapping the hole, filing the casting flat, and installing the screws.  Drilling the hole is simple, just place a small piece of wood inside the carb to prevent the tip of the drill bit from dinging the opposite side of the carb when it goes through.  Tapping the threads is also easily done, however be careful to use a good quality tapping fluid and run the tap in slowly; half turn in, quarter turn out, etc.  Breaking the tap off is an exceedingly bad idea.  Make sure to file off enough material at the end of the casting, about ¼”, so that the idle screw can raise the carb slide.  Once installed, you can remove control box, the parking brake switch and thumb throttle switch (follow the wires to a connector and either disconnect it or cut the wires).  Be sure to clean the carbs thoroughly and use compressed air to blow out any drill filings, and check the throttle cable free play.  More details on installing the kit can be found at www.toomey.com in the tech section.

Q#22:OK I know the parts of the ignition system how does it work?
A#22:Basically, the crankshaft spins the flywheel around the stator, the stator then produces electricity and sends it through the wiring harness to the CDI, at the same time the pickup coil senses the tabs on the flywheel and sends a signal to the CDI.  Depending on engine RPM, the CDI takes the electric current from the stator and the signal from the pickup coil, and sends an electrical pulse through the wiring harness to the coil, which steps up the voltage and fires both spark plugs.  For the ignition system to work (and the bike to run), the flywheel has to be indexed to the crankshaft at the right position with a woodruff key and the flywheel nut torqued properly so the flywheel can’t spin on the crank, the stator needs to be intact (not shorted or broken circuit internally) to produce electricity, the pickup coil needs to be intact and positioned with the correct gap from the flywheel tabs, the stator plate needs to be mounted securely to the engine bottom end, the CDI and coil need to be intact, the wiring harness needs to be intact (not broken wires or shorting to the frame), all wiring harness connectors need to be connected and making a complete circuit on both sides (not loose so electricity can’t travel through), the spark plug wires need to be connected between the plugs and the coil, the spark plugs need to be gapped and operational (not fouled), and finally both the handlebar kill switch and the key switch need to be “on”.

Q#23:That makes sense, sort of, but I want a basic electrical system overview…
A#23:If you’ve never messed with an electrical system, check this out.  On a relatively simple electrical system like a Banshee has, it’s all about generating electricity just to fire the spark plugs.  When electricity is produced by the stator and flywheel, it has a positive charge, and really wants to find the easiest path to negative, or ground…like water flowing down a river.  Along the way, we can use the electricity to do stuff for us, in this case we want it to fire the spark plugs at just the right instant, in the water analogy, it would be like having a waterwheel using the flowing river to turn.  So it’s very important for the wiring and connectors to make a complete path between the source or electricity (the stator) and ultimately the ground (the motor and frame), since the spark plug is connected to, or “grounded” to the motor, this is the end of the electricity’s journey; making a fat spark between the electrical supply and the ground strap of the spark plug.  If the river was dammed it wouldn’t flow, so couldn’t turn the waterwheel, with an electrical system the same is true if a wire is broken or if the ground wire is loose, unattached, or not making a good connection to the frame.  If the water or electricity’s path is unobstructed, like without a dam (water) or broken wire (electricity), it makes a “complete circuit”.  If it does have an obstruction to flow, it makes an “open circuit” and cannot operate.  Another electrical term is “short circuit”, in which case the electricity has taken a path to ground before we wanted it to, as if the river was diverted away from the waterwheel before it got there, again rendering it useless.  While the CDI, coil, wiring and switches can make a Banshee electrical system seem much more complex, each part of the system has a function and can easily be diagnosed when problems arise, as long as you know what each component is supposed to do.

Q & A, Testing

Q#24:What do I need to test the Banshee electrical system?
A#24:This FAQ, an Ohmmeter, and some patience.  A factory or Clymer manual is always a good source of information, and usually will have good illustrations as well.

Q#25:What’s an “Ohmmeter”?
A#25:An Ohmmeter is a small instrument used to test for “resistance” in an electrical circuit.  Back to the water analogy from Q#23, resistance is a measure of how much water is flowing down the river, or if it’s flowing at all.  In electrical terms, you can test resistance through a wire to make sure that it isn’t broken between two ends (this is important because even if a wire looks fine on the outside, the copper wire inside the plastic insulation can be broken in half), this type of test is called “continuity”.  You can also use an Ohmmeter to test the stator and coil, in this case you would be looking for a certain resistance, or amount of Ohms, from the specs above to tell if the components are OK; if you tested it and found an abnormally high Ohm reading, it’s possible that the internal wiring of the device is broken (an “open circuit”); if you see a very low Ohm reading, it’s possible that it has a “short circuit” or the internal wiring is melted together where it shouldn’t be.  Just remember that Ohms tell you how easily electricity can flow through a wire.

On a side note, I prefer a DVOM for testing, or Digital Volt/Ohm Meter, and one that emits a tone or “beep” when testing continuity is really cool.  On these meters, when you set the instrument to check continuity, it will beep at you when you have a complete circuit (like if you touch the two leads together, or touch a lead to each end of a good wire).  This makes it easier to make continuity tests, even if you have to turn down the stereo in the background to hear it, because you don’t have to be looking at the meter to know if what your testing DOES have continuity.  The digital meters are also a little easier to read and can be found in many auto parts stores for around twenty bucks.

Here’s a good link on how to use an Ohmmeter or multitester:

http://www.acmehowto.com/howto/homemaintenance/electrical/multitesteruse.htm

Q#26:How do I use an Ohmmeter to test continuity?
A#26:To test for continuity, set the meter to “continuity check” if you have it, or “Ohms” if you do not.  Some meters will have different test ranges, but for continuity you can just set it to 10-100 Ohms.  Now simply touch one test lead (it doesn’t matter which one) to each end of the wire you want to test.  If your meter beeps, listen for the tone; if you hear it then that wire has continuity through it.  If your meter doesn’t beep, look at the meter reading; a very low Ohm reading (close to 1 or 0) means that you DO have continuity through the wire and it is OK; a very high reading (the needle pegs out on an analog meter or the digital meter reads “- -“, or infinite Ohms) means that the wire is broken somewhere and electricity cannot flow through it.

Be careful with connectors!  Don’t cram the test leads into the connector you’re testing, as this will sometimes bend the little terminals (the tiny copper or gold colored metal things inside the plastic connector, which are crimped to the wire on one side and make contact with another terminal when the connectors are put together)  and when you put it back together they will not make a complete circuit.  All you need to do is touch the test lead to the terminal inside the connector, and the terminals should be clean to make a good contact.

Don’t test for continuity while the motor is running!  Continuity is tested without electricity flowing through the wires.  In fact, you can test for continuity with the wiring harness completely removed from your Banshee.  Although unlikely, it’s possible to fry your ohmmeter, and you probably won’t get the readings you’re after.

Q#27:How do I use an Ohmmeter to test resistance?
A#27:To test resistance, set the meter to “Ohms”, if several ranges are available on your meter select the one closest to what you are looking for.  For example, if you’re testing the ignition coil of the stator, set the meter to read 10-100 Ohms.  Then touch one test lead to each of the terminals that the wire color you’re looking for is attached to (in the ignition coil example, put one test lead on the terminal for the red wire and the other test lead on the green wire’s terminal), then read the meter to tell how many Ohms of resistance are between the two test leads.  When testing resistance, it DOESN’T matter which color test lead you put where, like continuity you are just testing how much, if any, electricity can flow through.  In a Banshee application, there are no components (other than inside the CDI) that you can test that will matter which way electricity can flow.  So in the example, it doesn’t matter if you put the black test lead on the green wire or the red wire, or the red test lead on the green or red wire, the results will be the same.

Again, be careful with the connector terminals and don’t test resistance with the motor running!

Q#28:How do I test for spark?
A#28:One of the easiest and most common electrical system tests is to check for spark.  You don’t need anything except a wrench to remove a spark plug to do this.  Make sure both the key switch and the handlebar kill switch are “on”, and it would be a good idea to turn off the fuel.  Remove one spark plug cap, and then remove that spark plug.  Stick the spark plug back into the cap, and hold the end of the spark plug against the cylinder head (the very tip of the spark plug that is usually inside the motor has a small metal strap on one side, hold that “ground strap” against the top of the motor or one of the head nuts).  Now watch the tip of the spark plug and kick the motor over.  You should see a fat, blue spark at the end of the spark plug, that’s a pretty good indication that your ignition system is operational.  If you don’t see a spark, try kicking it a couple more times, or try holding the ground strap against another metal part of the motor.  It’s also easier to see the spark out of direct sunlight, so don’t panic, get it into a garage and it will be a lot easier to see.

Q#29:How do I test the Ignition Coil on the Stator?
A#29:Using an ohmmeter and the specifications above, check the resistance between the red wire and the green wire on the four-wire harness coming out of the stator.  Find the four-wire connector (usually white), at the front of the airbox on the right-hand side of the bike.  Depress the little plastic retainer on the connector and disconnect the two connector halves.  Take a look at the wire on the connector towards the front of the bike, it should run under the carbs and into the left-hand side of the motor’s bottom end.  That is the connector you want to test.  On the back side of the connector where the wires enter, locate the red and green wires.  Set your ohmmeter to test resistance (and the correct range if you need to), and touch one test lead to the terminal on the red wire, and the other test lead on the terminal on the green wire.  Your ohmmeter should read between 13.7 and 20.5 Ohms, so if it reads 15 Ohms your stator ignition coil is OK, if it reads “- -“ or infinite Ohms or anything less than 13.7 or more than 20.5, then the stator is shot.

Q#30:How do I test the Pickup Coil?
A#30:Same as above Q#29, except you will be testing between the red & white wire and the green & white wire in the four-wire connector.  You should have between 94 and 140 Ohms between these two wires.  An important note is that the pickup coil needs to have the correct gap between it and the flywheel tabs.  To check the gap, rotate the flywheel until one of the tabs on the outside lines up with the pickup coil (either by hand or by moving the kickstarter slowly).  The gap should be between 0.015″ and 0.020″, if you need to adjust the gap loosen the two small Phillips-head screws where the pickup coil mounts and relocate it, then retighten the screws.  If you’re in a real bind, you can use a matchbook cover to check the gap, it’s about the same thickness.  Just like adjusting valves on a 4-stroke motor, the feeler gauge should slide easily into the gap with just the slightest drag, it should not be a bitch to cram the feeler gauge in there (that’s too tight!) and you shouldn’t be able to bounce the feeler gauge back and forth inside the gap (too loose!).

Q#31:How do I test the Lighting Coil on the Stator?
A#31:Similar to Q#29 above, check the resistance between the single yellow wire and the single black wire coming out of the stator.  Usually right near the four-wire connector at the front of the airbox on the right-hand side of the bike, you will find the two single wires with hooded bullet-style connectors.  Simply pull the connectors apart, and test between the yellow and black wire that leads to the stator.  Your ohmmeter should read between 0.26 and 0.38 Ohms.

Q#32:How do I test the coil and spark plug caps?
A#32:Locate the coil on the bike, it’s bolted to a frame rail just forward of the right cylinder.  Unplug the orange and black wires from the wiring harness to the coil, and pull the spark plug boots off the spark plugs, then use a 12mm wrench to remove the coil mounting bolts.  Many bike shops and dealerships have a bench tester for coils, if they’re nice they might just test it for free…in addition, resistance tests may test OK but the coil can still be bad, so if possible have it bench tested or swap in a known working coil to be 100% certain, even if you got to pay a little bit for it.  To test the coil, use an ohmmeter to first measure the primary side resistance between the “+” and “-” terminals that connect to the wiring harness, you should have between 0.28 and 0.38 Ohms.  Next test the secondary side resistance between the “-” terminal and the connector inside EACH spark plug boot, you should have between 4,700 and 7,100 Ohms in each one.  If the secondary side test shows an open circuit (infinite resistance), remove the spark plug cap and test directly to the wire, if you then get the right resistance, replace the spark plug cap and test again; if it’s still infinite the cap is bad.  If you still show an open circuit at the end of the spark plug wire, remove the wire at the coil and test again; if  it is still infinite Ohms, the coil is shot, if not the spark plug wire probably is bad.

Q#33:How do I test the handlebar kill switch?
A#33:Using an ohmmeter, test for continuity between the black ground wire and the white & black wire, when the switch is “off” there should be continuity between the two wires, when the switch is “on” there should be an open circuit.  Find the connector for the handlebar kill switch and light switch, usually located around the bottom front of the fuel tank (you may need to remove the fuel tank to get to it).  Depress the little plastic retainer on the connector and disconnect the two connector halves.  Put the ohmmeter test leads on the black and white wires on the switch side of the wiring harness, with the switch set to “on” you should have infinite resistance or an open circuit (no electricity can flow).  When you turn the switch “off” you should have continuity or a small amount of Ohms indicating that the circuit is complete (electricity can flow through).

Q#34:How do I test the key switch?
A#34:Similar to Q#33 above, EXCEPT the key switch works just the opposite; when the key is “on” there should be continuity between the black & white and the black & red wires on the switch side connector, and when “off” there should be no continuity.  On the wiring harness side of the switch (don’t ask me why the wire colors are different or why there are four wires on the switch), the CDI needs to have the black & red wire grounded to the black wire to run, and when that circuit is opened it will shut off.  See Q#60 on how to eliminate the key switch.  As above, test the key switch by checking for continuity between the black & white and black & red wires, except when “on” there should be continuity and when “off” there should be no continuity.

Q#35:How do I test the voltage regulator?
A#35:Check the blue wire connector and the black ground eyelet on the voltage regulator’s frame mounting bolt.  If that’s OK, and your headlights explode when you hit high RPM, it’s probably shot.  To test the voltage regulator, you’ll need to rig a tachometer, and test the DC voltage at one of the headlight connectors at two different RPM’s while the motor is running.  Remove one headlight connector by depressing the little plastic retainer and disconnecting the connectors.  Start the motor, turn the headlight switch on to “high” beam, and have someone hold the throttle keeping the motor at 2500 RPM.  With your DVOM (an ohmmeter won’t cut it here, you need a meter that can test DC volts) set to test DC voltage, touch the red test lead to the yellow wire on the wiring harness side of the headlight connector, and the black lead to the black wire in the same connector; it should read 11.5 Volts (if the reading is lower, test the lighting coil, see Q#31).  Now have your helper hold the throttle so the engine is turning 8000 RPM, with the meter test leads on the same terminals you should read 16.3 Volts, if it is above this reading the voltage regulator is toast.  If both tests check out OK, repeat the whole test with the red meter test lead on the green wire, with the light switch set to “low” beam.  You should get the same readings, if the voltage higher than specified, replace the voltage regulator.

Q#36:How do I test the wiring harness?
A#36:Using an ohmmeter, check for continuity between connectors for each wire color.  Simply unplug the connector at each end of the wiring harness that you want to test, and put one ohmmeter test lead on the terminal for the same color wire on both ends.  For example, if you wanted to check the wiring harness between the stator and CDI, unplug the connectors for each, put one test lead on the red wire terminal at the stator, and the other test lead on the red wire terminal at the CDI.  You should have continuity between the two, then move on to test the green wire, then red & white, then green & white.  If you have continuity for each wire color, then you know the harness is intact.  If you do not have continuity, first make sure the terminals are secured to the wires at the back of the connector, and that the terminals are clean (no rust or dirt inside the connector).  If there are no other visible problems, chances are the wire that has no continuity has been severed inside it’s insulation somewhere and will need to be replaced.  Here’s a pic of a stock wiring harness:

yamaha banshee wiring harness

Q#37:How do I test the CDI?
A#37:The short answer is, you can’t.  Since the CDI is a solid-state electronic device potted (or encased) in silicone, about the only thing you can check on it is to make sure the connectors are tight and the wires are secured to the connector terminals.  Short of buying an expensive replacement, the only way to test the CDI is to swap in a known working one.  For this reason it’s usually best to test every other electrical component first, if everything else checks out then chances are the CDI is toast. .  If you’re lucky you can swap in a known working one from a buddy to make sure, but that’s not always an option (see Q#61 if you can swap a CDI from a different year Banshee and the connectors are different, it is still possible to try it out by removing the terminals in the connectors).  It should be noted that MOST CDI failures are simply working or not (go or no go), so if the bike will run occasionally and other times it won’t, the CDI may not be the problem, but if it flat will not run and everything else checks out OK, it probably is the CDI that is bad.

Q & A, Troubleshooting

Q#38:My Banshee suddenly will not run, with no prior symptoms, WTF?
A#38:Many times electrical system problems will show up out of nowhere with no warning, one day you’re riding’ and the next day it won’t start at all.  If this happens, start with the simplest possible solutions and proceed from there.  Make sure it has fuel, the petcock is “on”, the handlebar kill switch is “on”, the key switch is “on”, and then test for spark (see Q#28).  If it has spark but will not run, look elsewhere before returning to the electrical system: it might just need the choke, new spark plugs, the air filter may be clogged, or the compression may be way low.  Kick it over 5 to 50 times and then take a look at the spark plug, if it’s wet chances are it isn’t starving for fuel, if fresh plugs don’t work, move on.  If everything else looks good, or you tested for spark and had none, start by testing the stator (Q#29 above), as this is a common failure (see Q#57 for tips on preventing stator failure).  After that, it’s a process of elimination, focus on the ignition circuit and disregard the lighting circuit, so test the pickup coil, continuity through the wiring harness, the coil, the plug wires, the handlebar kill switch, the key switch, and if everything else tests OK and you still have no spark, chances are the CDI needs to be replaced (Q#30-37 above).

Q#39:I recently installed a degree key, it ran great for a while then died, why?
A#39:If it was running after installation of the degree key, the most likely problem is that the flywheel nut came loose and either ate the key or spit it out.  Pull the stator cover and check the flywheel nut, if it is loose or fell off, remove the flywheel (see Q#48) and see if the key is intact.  If it spun loose, check for damage on the tapered end of the crankshaft and the inside of the flywheel.  If you replace the key make sure to install the flywheel correctly (see Q#48).  If the flywheel did not come off and the key is OK, make sure the problem isn’t non-electrical; too much advance can cause detonation, and on some motors just adding a degree key will cause a lean jetting condition and could lead to piston damage.  If everything else checks out, go through all the tests in Q#38, it’s possible that another electrical component just failed without having anything to do with the degree key.

Q#40:My Banshee runs fine until the upper RPM’s, when it cuts in and out, what is it?
A#40:A high-speed miss can be a symptom of the coil starting to fail.  If you’ve ruled out jetting or a broken reed, test the coil.  Also be sure to check the terminals from the wiring harness to the coil, as they will sometimes become loose and make a bad or intermittent connection (if loose, gently squeeze the female spade terminals on the wiring harness so they fit tighter on the coil terminals), and make sure the plug wires aren’t loose at the coil or the spark plug caps.

Q#41:I hit a huge water puddle and my Banshee died, what happened?
A#41:Banshees don’t really like water, and many times the stock carbs will stick wide open after hitting water, but when it dies chances are water has made its way into the stator.  Remove the stator cover and drain any water present, let it dry out and try it again.  For tips on waterproofing your stator cover see Q#57.  If the stator was dry or it still won’t run, check all the connectors.  If water has gotten inside, you can put a dab of dielectric grease inside the connectors to prevent water from causing problems in the future.  Again, if the problem persists start by checking for spark and then continue testing until you find the problem (Q#28-37 above).

Q#42:I was riding and it started to cut in and out at various RPM’s, what could it be?
A#42:Some of the hardest electrical problems to solve are the intermittent ones.  These are hard to test because sometimes heat or vibration while riding will cause the problem, but testing afterwards may not show any failures.  Some common things to check are the coil terminals (see Q#40), the wiring harness where a wire may have rubbed against the frame and shorted out (this may not show up with a continuity test but will be visible, although you may need to remove the wiring harness to find it), and the stator (along with testing resistance you can inspect it for any visibly loose wires or solder joints).  If  everything tests OK (Q#28-37 above) and you’re certain it isn’t a jetting problem (which will usually be limited to a certain throttle position, unless it’s WAY off) or other mechanical problem (exhaust or intake restriction, broken reed, etc.), then most likely the stator is bad (see Q#29-30), with a slight chance that the CDI is dying (see Q#37).

Q#43:I recently replaced my stator and now it won’t run, why?
A#43:Start with the simple checks; check the new stator’s resistance just in case you got a DOA unit (it happens), see Q#29 & 30 and make sure to check the pickup coil gap; make sure the connectors are all tight; pull off the stator cover and check the flywheel (see Q#39) and the wiring behind the stator plate for the stator and pickup coil, it may have been cut or pinched against the motor during assembly.  If everything checks out OK, test everything else (Q#28-37 above), there’s an outside chance that the stator was not the original problem (if you replaced it because of an electrical failure), or that another component failed at the same time.

Q#44:My headlights keep blowing, why?
A#44:The most likely problem is the voltage regulator (see Q#35).

Q#45:I suddenly have NO lights, what’s wrong?
A#45:Check the bulbs first, they may have just gone out from old age or vibration.  Check the stator lighting coil resistance next (see Q#31), then test the wiring harness connectors and continuity (see Q#36) making sure to check the ground, and finally take apart the handlebar light switch and check out the switch itself.  The light switch may have gotten water (unlikely) or filth inside, or the contacts have simply worn out.

Q#46:I replaced the spark plugs and it doesn’t run right, what’s the deal?
A#47:Make sure you use new NGK BR8ES spark plugs or better NGK plugs (there are various types of fine wire, race, etc. plugs available, but opinions vary on how much they help; when in doubt stick with the BR8ES plugs unless you have a VERY highly modified motor that requires a different heat range).  Check the spark plug gap, make sure the little tit on top of the spark plugs are tight, make sure the spark plug caps are clean inside where it connects to the spark plug, and make sure the plug is tight in the cylinder head (don’t torque it like crazy!  On new plugs about one full turn past finger tight will seat the sealing washer, on old plugs it takes closer to a quarter turn past finger tight).  Also make sure the spark plug wires are connected to the coil securely.

Q & A, Removal and Installation

Q#47:I need to replace my stator, how do I do it?
A#47:Removal-Unplug the stator connectors, coming from the left-hand side of the bottom end of the motor and routed under the carbs towards the right-hand front of the airbox, there is one four-wire connector (usually white), and a single yellow and black wire with a hooded bullet-style connector.  Depress the plastic retainer on the four-wire connector to disconnect the two halves, and simply pull the two single-wire apart.  Remove the plastic stator cover on the left-hand side of the bottom end of the motor (typically you’ll need to remove the shift lever with a 12mm wrench by removing the bolt and sliding it off the shift shaft splines, remove the left-hand footpeg with a 17mm wrench by removing both bolts, and then removing the seven Phillips-head screws on the stator cover).  Remove the flywheel (see Q#48).  Remove the three bolts securing the stator plate to the motor with either a 12mm wrench or a Phillips-head screwdriver.  Push the wiring boot just above the stator plate out of the hole in the bottom end of the motor, and pull the short wiring harness through the hole.  Pull the stator assembly away from the motor.  If by chance you are not replacing the entire assembly (aftermarket stators typically come mounted to the stator plate, along with the pickup coil), remove the stator from the plate by removing the three Phillips-head screws, and remove the wiring from the short rubber grommet (this is a BITCH, once the electrical tape is removed if present, the wires don’t want to go back through the grommet without cutting off the bullet-style connectors, luckily you can find these connectors at most auto parts stores.  You can remove the terminals from the four-wire connector to get them through, see Q#61).  Make sure you note how the wires are routed around the stator plate.

Installation-While not entirely necessary, it doesn’t hurt to test the resistance on the new stator before you install it, just in case it’s DOA (see Q#29-31).  If your stator didn’t come mounted to the stator plate, install it on the plate with the three Phillips-head screws and carefully route the wires through the stator plate and through the rubber grommet.  Hold the stator up to its mounting location and push the connectors through the hole in the bottom end of the motor, routing the short harness under the carbs towards the wiring harness connectors, then push the rubber grommet in place in the hole.  Use a little anti-seize compound on all the bolts and screws (I recommend this stuff whenever you’re putting a steel bolt into aluminum).  Thread the three stator plate mounting bolts through the plate and tighten them (if it is a tight fit, tighten the bolts in a circular pattern a turn or two at a time so you don’t warp the plate).  If you are going to advance the timing with the stator plate by slotting the holes (see Q#56), or you have an aftermarket plate that is already slotted, line up the adjustment mark that you want to set the timing to with the line where the case upper & lower halves meet just to the right (or rear of the bike) of the stator plate, and tighten the stator plate bolts.  Install the flywheel (see Q#48), and set the pickup coil gap (see Q#30).  Reinstall the stator cover, footpeg, and shift lever, and then plug in the four-wire connector and the two single wires to the wiring harness.

Q#48:I need to replace the flywheel or key, how do I do it?
A#48:Removal-You will need to invest in a flywheel puller tool, these are available for $10-20 all the time on eBay, or double or triple that at your local dealer.  Do not use a jaw-type bearing puller!  Same goes for prybars, hydraulic jacks and C4, these can all damage the flywheel and should be avoided.  Some flywheels don’t want to come off even with the tool, so you may also need some of your favorite flavor of penetrating oil (WD40, panther piss, etc.).  Remove the stator cover (see Q#47 above).  Using a 17mm socket (19mm on RZ350′s), remove the flywheel nut.  The BEST way to remove the nut is with an impact wrench, you won’t even need to hold the flywheel, the impact will spin the nut right off.  If you’re in a bind and cannot use an impact (really, the impact is way better), you can use a rubber or fabric strap-type oil filter wrench to hold the flywheel while removing the nut, but if it’s not the right length it may not work very well and you risk damaging the flywheel tabs or busting your knuckles when the strap wrench invariably slips.  Motion-Pro makes a flywheel/clutch holder tool that would be one of the best options if an impact is unavailable.  If you’re industrious, you can fabricate a flywheel holder out of a short (about 12”) piece of metal and two 3/8” bolts; simply measure the centers of two of the holes in the flywheel’s center section, drill the metal with two holes at the same distance apart at one end, and mount the bolts to the metal piece with a nut so that the bolt extends past the nut.  Then simply use the new tool to hold the flywheel by setting the ends of the two bolts into the flywheel.  Depending on how many holes are in your flywheel, you may need to use two holes opposite of each other (3-3/8″ from center to center), in that case you’ll need a hole saw to drill a hole in the center to get a socket on the flywheel nut, like mine (shown with an RZ350 flywheel):

yamaha banshee flywheel

yamaha banshee flywheel

yamaha banshee flywheel

yamaha banshee flywheel

Here’s a couple pics of a custom flywheel holder, which will engage two holes on the side of the flywheel:

yamaha banshee flywheel holder yamaha banshee flywheel holder

Once the flywheel nut is loose, carefully thread the outside of the flywheel puller tool into the center of the flywheel until it bottoms, remember that the fine threads on the inside of the
flywheel are left-hand so thread it in counter-clockwise (you may need to back the center bolt out all the way first so it doesn’t hit the end of the crankshaft before the outside threads bottom out in the flywheel).  Then thread the center bolt in until it contacts the crank, finger tight.  Using two wrenches, hold the

outside of the tool and tighten the center bolt on the tool fairly tight (not 6-foot cheater bar tight!  the flywheel has very fine threads and is easily stripped, so just tighten it about a quarter or half turn, so that the tool is putting tension on the flywheel away from the crank…for you detail freaks probably about

20-30 ft-lb. of torque).  Now take the wrenches off the tool and hit the center bolt on the flywheel puller tool with a hammer (not a sledge!  a ball-peen, dead-blow or small mallet is fine).  If the flywheel hasn’t popped off the crankshaft after putting tension on it with the tool or a couple whacks with the hammer, remove the tool and soak the center of the flywheel with penetrating oil.  If the motor is out of the bike turn it on its right side so gravity can help the oil soak in between the flywheel and the crank.  If the motor is still in the frame, flip it up on its right side wheels (turn off the fuel first) so the flywheel is pointing straight up, and use a short 2×4 or something against the frame to hold it up.  Let the oil soak in an hour or ten (you may need to hose it down with penetrating oil every day and let it sit for a couple days if it really doesn’t want to come off), then thread the tool back in and try again (remember to just tighten the tool enough so that it has tension on it and then hit it with a hammer, sometimes you’ll feel it move a little bit but won’t pop off so as long as it’s moving keep going with the process of tighten, hammer, tighten, hammer).  Once you get the flywheel off, DON’T DROP IT!  Dropping it or hitting it directly with a hammer can render it useless, the flywheel is magnetized and an impact can demagnetize it, and if the tabs are broken off you got yourself a paperweight.  The last thing to do is remove the woodruff key from the crankshaft, it should pop right out but may need a little persuasion with a light tap.  Here’s a pic of Meat’s flywheel remover tool being threaded into the flywheel, then tightening the center bolt:

yamaha banshee flywheel yamaha banshee flywheel

Installation-Get some anti-seize compound and coat the end of the crankshaft (not the threads!) and the mounting area of the flywheel lightly, along with the woodruff key and keyway on the crank.  Set the woodruff key in the keyway on the crankshaft (this is a lot easier if you turn the crank so the keyway faces straight up), if you are installing a degree key make sure the offset is in the right direction (with the crankshaft key facing up, place the key in the crankshaft slot with the offset facing the left, or front of the motor).  Align the keyway on the flywheel with the woodruff key, and make sure the key doesn’t move when you slide the flywheel in place on the crank.  Clean the threads on the end of the crank, put some blue (medium) loctite on them.  Install the lock washer and then the nut.  Use a 17mm socket to tighten the flywheel nut, and use a flywheel holder tool (see Removal above) to torque the nut to 59 ft-lbs.  Make sure you torque that nut!!  The last thing you want is that nut to come off 50 miles from nowhere, so take the time to torque it right.  An impact might get it tight enough, of course it might just strip the nut out (or worse the end of the crank!).  Double check the pickup coil gap (see Q#30), and install the stator cover.

Q#49:I need to replace the coil, how do I do it?
A#49:This one’s easy, simply disconnect the orange and black wires from the wiring harness on the right-hand side of the coil, remove the spark plug caps, and use a 12mm wrench to remove the one mounting bolt.  Installation is the same thing in reverse, but one thing to check is that the coil makes a good ground to the frame at the mounting bolt, if it is painted or powder coated you may need to scrape off the coating so that it is bare metal where the coil mounting bolt secures the coil.  You can also use a little anti-seize on the bolt to prevent rust, as well as a little dielectric grease on the wiring harness connectors to keep water out of the wiring.

Q#50:I need to replace the CDI, how do I do it?
A#50:The CDI is even easier than the coil; all you need to do is unplug the two four-wire connectors (later models may have one five-wire and one four-wire) by pushing in on the plastic retainer and disconnecting the two connector halves.  Remove the two 12mm bolts on the bracket holding the CDI, and remove it.  Again installation is just the reverse, and you can use some anti-seize on the bolts and dielectric grease on the connectors to prevent corrosion.

Q#51:I need to replace my voltage regulator, how in the world can I do it?
A#51:OK don’t let the sarcasm get to you but a trained monkey, or even a dealer-employed mechanic is qualified to replace the volt reg (just kidding!  damn!!).  Unplug the single blue wire from the wiring harness, and remove the two 12mm bolts.  Installation is just as painless, but you need to make certain that the black ground wire with an eyelet makes a good ground to one of the mounting bolts (see Q#49 above).  Again you can use anti-seize on the bolts and dielectric grease on the connector.

Q#52:How do I replace the wiring harness?
A#52:Oh boy, you’re screwed, you might as well sell it right now.  Not!  The easiest way to replace the wiring harness is to start at the CDI, run the new harness alongside the old one, and simply unplug the old harness connectors and plug in the new ones.  Take care to route the wiring harness along the same path as the old one, and if it gets close to the pipes try to keep it far enough away so it doesn’t get burnt.  Use the factory ties if possible, and if you use zip ties don’t make them super tight or the wiring harness will be more prone to rubbing the frame and causing a short circuit.  You will probably need to remove the fuel tank to get to the connectors and wiring to the handlebars.  Also you can use dielectric grease in all the connectors to prevent corrosion.

Q#53:How do I replace the light switch, key switch, headlights or taillight?
A#53:All of these are simply a matter of tracing the wires to a connector, unplugging it, and installing the new one.  Headlight and taillight bulbs can be replaced by taking their housings apart (or removing the lens) and changing out the bulb.

Q & A, Electrical System Modifications

Q#54:What is “advanced timing”?
A#54:Advancing the ignition timing is an age-old method of extracting a few more horsepower out of a 2-stroke engine.  Typically when a motor leaves the factory it’s detuned for reliability and ease of use, advancing the timing can give you a couple ponies cheap or free, without risking damage, as long as you don’t go too far.  By advancing the timing, you alter the time that the spark plug ignites the intake charge.  If the spark plug fires earlier due to advanced timing, more of the intake charge can be burned, and more efficiently, producing more power.  In its factory detuned state, a Banshee will benefit from advanced timing, and together with other simple mods can quickly make a lot more horsepower (some dyno testing shows about 2hp gain from 4 degrees of advance).  However, too much advance can quickly cause detonation and/or overheating problems, so it’s best not to go beyond about 4 degrees of advance unless you are building a dedicated drag racer or plan on running high octane fuel.  Also remember that your jetting may be affected by timing advance, and reading your spark plug can give you an indication of too much timing advance or detonation.

Q#55:How do I advance my timing?
A#55:There are three ways to advance the timing; a degree key (see Q#10), slotted stator plate mounting holes, or an aftermarket CDI.  Degree keys are relatively cheap, fairly easy to install, and are usually available in 4 degree or 7 degrees of advance (typically 4 degrees is perfect for all but drag racing ONLY applications, where the 7 degree key is used on gas motors) .  Aftermarket adjustable stator plates cost more and are a little harder to install, but offer the advantage of being able to easily adjust the timing anytime by loosening the stator plate bolts and rotating the plate, or by loosening the pickup coil screws and adjusting the pickup coil mount.  Your stock stator plate can be modified by elongating the mounting bolt holes (see Q#56 below).  Adjustable stator plates also offer the benefit of being able to go much farther than 7 degrees of advance or even retard the timing, however both of these scenarios only apply to seriously built alcohol or other exotic-fueled drag racers.  Aftermarket CDI’s are by far the most expensive, but are also way way easier to install and offer the greatest adjustability (depending on model) and flexibility.  An aftermarket CDI may also offer side benefits such as hotter spark or outputs for shift lights or nitrous oxide solenoids.

Q#56:How do I modify my stock stator plate to advance the timing?
A#56:First of all, you need to make a mark on the stator plate to use as a reference for advancing the timing.  Once the stator cover and flywheel are removed (see Q#47), etch a mark on the stator plate on the right side (or towards the rear of the bike) of the stator plate where the upper and lower case halves meet.  This mark will be your “zero advance” reference mark.  Next remove the stator assembly and find a tool to slot the mounting holes.  A Dremel tool with a straight carbide burr works well, or any other rotary tool that will fit in the stator plate mounting bolt hole (about 6mm in diameter) and cut the aluminum material will work, a drill bit does not work very well, nor do most grinding stones since they will load up quickly.  With the stator plate sitting on a workbench, with the stator coils and pickup coil facing upwards, use your cutting tool to elongate the three stator plate mounting holes counterclockwise, along an imaginary circle that is the diameter of all three bolts.  In other words, don’t just slot the holes in a straight line as the bolts won’t go in; you need to curve the slot so that when the stator plate is mounted loosely with the bolts, it can rotate.  You only need to elongate the holes about 1mm for every degree of timing advance you want to add, so if you’re going for 4 degrees of advance slot the holes about 4mm longer.  Remount the stator plate with the bolts finger tight and align your reference mark where the upper and lower case halves meet.  Now rotate the stator plate clockwise, one millimeter for every degree of advance you want to run, by using the reference mark relative to where the upper and lower case halves meet.  Tighten the stator mounting bolts, reassemble everything (see Q#47), and verify your jetting just in case (see the Jetting FAQ).  Here’s a pic of a stator plate modded for up to 5 degrees of advance:

yamaha banshee stator

Q#57:How can I waterproof my stator?
A#57:The stock stator doesn’t have the best water protection.  The problem (I think) lies in the bottom case half casting.  Just to the right (or towards the rear of the bike) of the stator and pickup coil is a notch on the bottom case half.  This notch was used on the RD/RZ350 street bikes, which the Banshee motor is derived from, for a short wire that goes to the neutral sensor.  You’ve no doubt noticed the little white plastic cap just below the front sprocket, well on the street bikes there was a small spring-loaded nub on the inside of that cap that extended into a hole on the end of the shift drum when the transmission was in neutral, thereby signaling the neutral lamp to light up.  These bikes had a rubber grommet for that wire where it passed through the bottom case half (the wire was run alongside the stator wires through the upper case half hole and grommet) so that the stator was sealed off from the relatively open area where the front sprocket sits.  For some reason, most Banshees do not have a grommet there and the rubber stator cover gasket doesn’t seal off the little casting hole.  So if you are getting water into the stator, first check that the rubber gasket on the stator cover is intact and replace it if necessary, and then add a small rubber plug in that hole, or seal it with silicone.  You can cut a small (about 1cm) piece off the stator cover gasket itself to plug that hole, just cut it off the very rearward part of the gasket above the front sprocket where it really isn’t sealing anything off anyway.

Q#58:What’s the right way to install a tether kill switch?
A#58:While some people run both wires of a tether kill switch to the coil, and this does work, it may cause damage to the CDI.  The best way to wire a tether (or pushbutton) kill switch is to use the handlebar kill switch circuit.  When the black/white wire on the handlebar kill switch is grounded, the CDI kills the motor.  All you need to do is ground one of the tether wires to the frame (or splice it to the black wire for the handlebar kill switch), and splice (see Q#59) the other wire onto the black/white wire somewhere.  If you bought it new, the tether switch should have instructions indicating which wire should be grounded and which one grounds when the tether is pulled (if you’re not sure which is which, temporarily splice the wires one way but don’t cut them until you know it works).  I prefer a solid ground to the frame just in case, so I like to use a nylon solderless eyelet terminal on the ground wire (you’ll need a wire stripper and a pair of crimpers along with the terminal, but you can find all of it at an auto parts store) and attach it to one of the tether wires.  Make sure you don’t cut the wire too short to reach a frame bolt, once the terminal is crimped in place make sure it contacts bare metal on the frame and tighten the bolt (you can use any of the bolts that thread into the frame, like the coil mounting bolt, the upper steering stem mount, etc.).  Now splice the other tether kill switch wire to the black/white wire.  If you’re eliminating the handlebar kill switch (not really a good idea unless you mount a pushbutton kill switch in its place, having a kill switch you can easily reach with your left hand while holding on to the handlebars is a good idea in case of emergency, you may not have time to yank the tether out or be able to get one hand off the handlebars), simply cut the black/white wire somewhere between the old switch and the wiring harness connector and splice the tether switch wire to it (you can also splice the other tether switch wire to the black wire if you don’t want to use a frame bolt for the ground).  If you are keeping the handlebar kill switch, you’ll either need to skin the insulation off the black/white wire somewhere and splice the tether switch wire to it, or use one of those 3m Scotchlocks to piggyback onto that wire.  Before you go crazy with the electrical tape, test the tether kill switch!  With the tether installed, the motor should run, and when you yank out the tether, it should die.  If it doesn’t, first make sure the splices and/or ground is making good contact, then try swapping the two wires (move the ground wire to the black/white wire, move the one that was on black/white to ground…some tether kill switches will only operate one way).  Make sure any splices are thoroughly taped with electrical tape, use zip ties to route the wires if necessary (don’t make them too tight or the wires can rub through!), and for a clean appearance tape the wires alongside or onto the existing wiring harness in a spiral pattern along the wh
le length.

Q#59:What’s a splice and how do I make one?
A#59:A wire splice is essentially just connecting two wires.  If you are simply splicing the end of one wire to the end of another, you can (in order of best to worst):

1.Strip the insulation off each wire, twist them together, solder the joint, slide heat shrink tubing over the connection so it extends past the insulation on both wires at least 2cm, and use a heat gun to shrink the tubing.

2.Strip the insulation off each wire, twist each wire separately (just to keep stray wires from sticking out), and crimp a nylon solderless butt connector between the wires.

3.Strip the insulation off each wire, then take one wire and separate the conductors (all the little tiny copper or aluminum wires that were inside the plastic insulation before you stripped it) in half so it makes a “V”, and then twist each side of the V together tightly.  Take the other wire and do the same thing, so you have two “V’s”.  Now push the two V’s together and twist one half of the V on each wire together, then twist the other half of the V on each wire together, and finally twist both of your twisted wires together.  Fold the twisted wires back onto the insulation of one of the wires and wrap the whole mess with electrical tape in a spiral pattern along the whole splice.

Now if you’re splicing the end of a new wire to the middle of an existing wire, you can:

1.Same as #1 above except you’ll need to carefully “skin” the insulation off the middle of the existing wire to expose the conductor wires.  Be careful not to cut the conductors, and before soldering wrap the stripped end of the new wire tightly around the existing wire conductor.  Once soldered, lay the new wire alongside the existing wire and slide the heat shrink tubing over both wires on one side. You may not be able to get the heat shrink tubing over the solder, in that case
you’ll have to tape over it with electrical tape.

2.Use a 3M Scotchlock to piggyback the new wire onto the existing wire.  These things have a small aluminum thing inside that (usually) makes contact with the conductor wires when you snap them shut.  They don’t always make a good contact however, and you need to get the correct size for the wire you’re working with.  The plastic tab that holds it shut is kinda flimsy too so it’s best to tape over them once installed.

3.Same as #3 above, except your “V” will just be twisted onto the existing wire.

Q#60:How do I eliminate my key switch?
A#60:The key switch operates just the opposite of the handlebar kill switch; when the red/black wire from the CDI is grounded, it is “on”, when the red/black wire is not grounded, it is “off”.  To eliminate the key switch, simply trace the wires from the switch to the connector on the wiring harness (you’ll probably need to remove the fuel tank to reach the connector) and unplug it.  Either cut the black/red and black wires off and splice them together, or re-use the switch side connector to make a jumper wire.  I prefer re-using the connector for a good weatherproof seal, to do this all you need to do is remove one terminal from the connector on the switch side (see Q#61 below) for the black/red wire, uncrimp the terminal from the wire, cut the black/white wire about an inch or two away from the connector, strip the black/white wire and crimp the terminal on, and stick the terminal back into the connector.  Then simply cut off the red and brown wires off on the switch side of the connector.  When you’re done and connect the two connectors together, the red/black wire and the black wire on the wiring harness side will be looped together and make a complete circuit.  On a side note, you can also re-use the two-wire TORS connectors instead of the switch side connector, as one of those connectors will fit right on to the key switch’s wiring harness connector (just make a jumper connector as above so the two wires are tied together).

Q#61:How can I remove terminals from a connector?
A#61:You may at some time need to remove the terminals from a connector.  One example is CDI testing; Banshee CDI’s have very little difference between year models from 1987 and up, so it is possible to use a different year CDI to test your own CDI, even if the connectors are different.  In this case all you need to do is write down what color wire goes where in each connector, remove the terminals from both the old and new CDI’s, and then put the new CDI terminals into your old CDI’s connectors, and you can hook it right up.  To remove the terminals, you’ll need a sharp instrument like a straight pick or ice pick, or the end of a large paperclip folded open.  When the connector is disconnected, look at the inside of the connector at the terminal itself.  You should see a small plastic retainer that you can push down with your pick.  The retainer will look like a small ramp, that when the terminal is shoved into the connector prevents it from coming out.  Some terminals have the retainer on the terminal, in which case you depress the little metal tab.  With one hand pull lightly on the wire that’s crimped to the terminal you want to remove (towards the wiring harness), and with the other hand depress the little retainer.  The terminal should slide right out the back of the connector.  To install the terminal into the connector, simply push the terminal in (make sure it is aligned correctly and not upside down) until the little retainer clicks in place and secures the terminal (unless you really mashed the retainer or have the terminal upside down it should not back out).  It should be noted that terminals are often different depending on the gender of the connector, so you can only put terminals for a female connector in another female, or male terminals in a male connector (typically a CDI will have one male and one female connector).  Here’s a pic of the CDI connectors, which are the same for ’97 and up Banshees (on older machines there will be two four-wire connectors, and depending on year can be round or square):

yamaha banshee terminal connector

Q#62:How do I wire in aftermarket headlights?
A#62:The easiest way to wire aftermarket headlights is to cut off the factory headlight wires between the headlight and the wiring harness connector.  Then you can simply splice the new headlight wires to the black ground wire and either the green wire (which will be “low” beam on the stock handlebar light switch) or the yellow wire (“high” beam), or both if your new headlights have a high & low beam.  If you want to remove the headlights you can just disconnect the factory connectors.  It should be noted that the factory stator lighting coil can only handle two 30-35W headlights, or about 70W total (a little more for the taillight).  If you use higher wattage bulbs with a stock stator they won’t damage anything, but will not be very bright (possibly dimmer than the stock lights!).  Also, if you are considering higher wattage headlights and want to upgrade your stator, be advised that some stators have a 70W circuit just like the stock stator, along with a separate, higher wattage circuit that will require another voltage regulator.  To my knowledge Ricky Stator’s higher wattage stators have only one lighting circuit with a higher wattage, so no additional wiring will be necessary.

Q#63:I want to eliminate the worthless junk in my wiring harness or make a new one…
A#63:If by chance you wish to wire the headlights (stock or aftermarket) so they are always on “high” beam, eliminate the key switch and all the TORS crap, here is a color-coded wiring diagram:

yamaha banshee

This article was written by Ben Boal, and is free to use as reference, or print off and throw in the toolbox. You may NOT sell this, or profit from this article in any way. It is written by a Banshee rider to help out other Banshee riders! This is intended as a guide only, and the author does not accept any responsibility for anything written here, or your actions that come forth form it; it is for reference only!

Comments

3 Responses to “Yamaha Banshee Q&A”
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