blowit

Agree with above. The very first question to be raised is where on the piston were they measured? Also, I would pull and ring and check the ring end gap for a comparison. When you mic a piston, you are looking for the largest value anywhere on that piston. That happens to be about 10mm below and normal to the wristpin centerline. Not looking to immediately go at shoddy measuring but as being a machinist and engine builder myself, I can firmly say not all machinists understand some specifics of engines, especially 2 strokes. The noises you hear could be coming from the clutch as well. heard it many times. Brandon Mull Engineering

They don't have a BIG spark kernel even on a good day so you might have full spark. Only thing I can tell you is learn how to use a multimeter and let that be your guide. IIRC, if the black/white is closed with the black going to the CDI, that is the kill circuit. ALL kills in the bike are referenced with that. The TORS, bar switch, key switch. When and only when you DON'T have spark, you need to test all electrics. Brandon Mull Engineering

From how it was explained, it sounded like either a weak spark issue or reeds. Weak spark only because it sounds like "spark snuffing" or blowing out the spark kernel during heavy breathing. Spark plug gap, grounds, connections, etc, any of those could cause it. Reeds can also be problematic though they typically show up at lower rpm too. Certainly not the park brake rev limit, as this kicks in just above idle and you indicate you were riding it.

I would say a good multi meter will take the guess work out of this. Follow the values and procedures in the manual and report back. No sense in guessing. Do you still have the TORS system on? The key switch, handlebar switch, and TORS are all part of the same circuit and an issue with any of them will cause the CDI to be in "off" mode. You can also set your meter to AC volts and the primary side of the ignition coil (NOT the secondary) and you should see activity there. You won't be able to get a good read on the voltage but activity means you are likely getting response from the CDI to the coil thus the ignition coil may have issues. Brandon Mull Engineering

Should you decide to repair it, heat is required to properly repair it. This is not a heat treated frame system. If you try to bend it back cold, you risk over stretching the steel and breaking it. Even if it does not break, it will be severely weakened if cold worked. Heat to a low cherry red and reform. do NOT quench with water, etc. Reinforcements can be added, if needed.

You are reading that wrong. The ignition coil by itself (no caps) will read between 4.7-7.1 kohms. The caps will be around 5kohms each. Add all that up and you have a circuit test with caps of about 15kohms. There is nothing wrong with you bike. Keep in mind, when testing in these ranges a few Kohms is nothing I would get worried about unless the system was not operating correctly. Typically we will see things swing well into the the mega ohm area when bad. This is the same as adding 3 resistors in series, NOT to be confused with parallel. In series, you simply add them.

It is not advisable to use LED lamps on the OEM AC lighting system in the Banshee, unless the lamps have DC modules built onto them. However, you may find that a DC regulator/rectifier is very worth while investment and will typically get the AC ripple down to tolerable effects for LED lights. Brandon Mull Engineering

You should be fine. Some aftermarket caps will measure slightly different but where concerns come in is when resistance is WELL out of range. Slightly out of range is not a concern as temperature can easily alter returned values, as does the meter itself. In our electronics work, we typically test a meter against a known high accuracy resistor to ensure meter accuracy. It is good practice and resistors are VERY cheap! Also FYI, do NOT use resistor type spark plugs such as BR8ES. adding additional resistance to the plug will only further reduce spark energy. Brandon Mull Engineering

Agree with above. Carb sync sounds most likely. You can simply swap your plug wires side to side. If problems follow the wire, you have a wire problem. If not, you have other issues. Remove the airbox or filters so you can see the slides. Sometimes you can peek through the box. You will likely see one slide much higher than the other. Reeds are certainly possible but the carb check might be an easier check first. In many cases over the years, we see people messing with something on the bike and get the adjuster on top of the carbs not "seating" right. Make sure the cable ends are in their home! We also see where the cable will fray and cause issues.

Sleeper, I agree that pipes may be causing some issue here but we built several for guys running those and never had one produce "no more power than it did before". I really think the squish and ex duration needs checked. It could be that the duration is so wild that those pipes will never work right. Or it could be a really piss poor dome setup. All I know is it would be hard to throw a 4mil crank and porting at an engine and NOT make more power, even by accident! I suspect you or someone experienced could just take a rip on the bike and figure out what is going on. I remember several coming in the door that were actually massive clutch slip problems! You can't run a 4mil on the stock clutch setup. I also remember a guy bringing us a bike because no one could figure out a "clutch slip" problem. That one was actually tires spinning on the wheels! He had ag bike tires on it.

Agree with above, you need to check the squish clearance as this may indicate some of what is going on. Beyond that, it might be wise to pull the head and verify the exhaust height so the duration can be determined. It sure sounds compression related though. Wrong pistons or wrong domes. You also mention having detonation issues. That can happen with very loose squish due to the flame front pretty much exploding, rather than getting a centralized controlled burn. You should NOT be having detonation issues with that setup, and timing can easily go beyond 4*.

What fuel are you running? What pipes?

Agree with sleeper on this. focus your money on porting. That is where you will find this best bang for buck! You can port for better pipes and change them later if you like, if you already have pipes. Here is what I would suggest, pipes depending on what type of power delivery you are wanting. T5, CPI, Shearer pipes, porting to match, advance timing to 4*, stock CDI, stock carbs, open air box. I would not waste the money for race fuel for this. Run 21cc domes up to 1000ft elev or 20cc for higher elev and run 91oct fuels. I would also suggest the extra effort to port the top crankcase. It requires full engine disassembly but there is power hiding in that port work. REMINDER - the CPI and Shearer pipes are high rev pipes. I see plenty of people buy them, get porting to match, just to get more top end HP they can brag about, but otherwise fight the bike riding in technical trails. If you will be in tighter riding areas, you will have more fun with FMF pipes and a little less aggressive port timing. Many people confuse porting and port timing. You can still have a very aggressive port job but with more mild timings and that makes for smoother power delivery. Brandon Mull Engineering

As a manufacture of shift stars and detent kits for the Banshee, we have received this question several times. There are a few things that can cause this. 1. The shift shaft return spring pin may need adjusted to ensure the shift claw is centered about the shift star. If the claw is touching one of the pins on the shift star, this can cause issues. 2. The clutch! Many advocate adjusting the clutch, which is a good idea, but many times it is actually wear or damage to the clutch system. If the clutch basket is notched or the steel drive plates are warped, this will cause the clutch to drag even with the lever all the way in. The clutch MUST fully disengage power to the transmission to find neutral. You would have to completely remove the clutch plates to inspect. Usually bluing on the steel plates is evidence they have been overheated and likely warped. Put them on the flat plate per the manual to check for warp. 3. Detent arm bind up a bit. Our roller bearing kit helps in many cases so the shift drum will roll smoother to feel for neutral easier. Brandon Mull Engineering

You can actually get it extremely close without a sync tool just by measuring and checking.

Your vid did not work for me but I will mention that you really need to first focus in on getting the carbs balanced or sync'd perfectly before you even consider your jets. I have seen all sorts of ridability issues from that. Once you do that, you can usually adjust the air screws to determine where to go with the pilot jets. Obviously if you run them out to 3 turns out and it runs better vs .5 turns out, you know the jet size may be a bit big. Brandon Mull Engineering

Sounds like a gear welded itself to a transmission axle. Can't remember right off but thinking it was 2nd that was known for this and the newer OEM gear now has a better bushing in it. We dealt with several over the years. Basically a gear that should spin free on a trans shaft welds itself on. Indications would be to remove the drive chain, then pull clutch lever and start bike. If engine will run but even slightly bogs engine when you try to engage clutch, the trans has issues. Brandon Mull Engineering

Sounds like either pilot jets are plugged TORS system is tripping because it needs adjusted. If the bike will run with slight throttle but acts like you hit the kill switch when you let go, it is likely the TORS. A plugged pilot will have some ridability issues at 1/8 throttle. TORS problem won't. If you have TORS still on, unplug the small black box under tank to test this. Brandon Mull Engineering

I would make sure the TORS system is in check. Either totally disabled or connected. If the TORS box is plugged in, unplug it. BUT, beware, if the TORS system is plugged in and it is not firing, it is likely indicating the carbs are partially open and it may run away on you. The TORS system works by looking for switches to be made on the carb tops and the thumb throttle box. If the TORS is disabled, look at the wiring diagram for the ground wire that returns ground the CDI for "off" mode from the switch, which stops the ignition. I have seen where the switches do not work right and simply unplugging that will enable the CDI for testing. Also make sure the key switch is working properly. A switch working correctly will show low ohms (1.0 or less) when closed, and OL when open. If the switch reads high ohms but not OL when open, there is a problem and the switches need cleaned or replaced. Brandon Mull Engineering

Sorry, I can only speak for our own impeller product, but we tested several competitor pumps and the proof was in the testing. Our pump just out performs. But I am not here to toot our business horn, just saying we did things DIFFERENT for a reason! We might have a small idea how to design a water pump. Now, relate this back to what I said earlier. flow rate vs pressure. If you take two pumps that move 10gpm at 0ft of head, the only other factor to determine which is best is the power used to run that pump. However, lets say you take those two pumps and restrict them so they are now pushing 10ft of head pressure. One pump drops to 5gpm, the other drops to 8gpm, who do you think is winning that one? Do you possibly see where "high flow" comes in? You might look at the 8gpm and say, OH, it flows more, its better. BUT, the reason is the pump is MORE EFFICIENT, has less slip, less heat generation, and can continue to move more fluid at high head pressures. If our pump can maintain higher pressures, it automatically pumps more fluid, you get more turbulent flow, and more cooling!! BUT, again, there are a LOT of variables in the cooling system. You grab our pumps and then throw in an 80% mix of Ethylene Glycol and you will still have problems. How does this relate back to your engine??? Your engine has restriction in the cooling system PLUS we want HIGHER PRESSSURE in the coolant system as this raises the boiling point of the fluid which reduces flash boiling in the cylinders. Our pump is designed to reduce the nasty losses you see in the OEM pump and other aftermarkets. Some really feel moving water is moving water. I would say go talk to NASCAR engineers about that. You want to pump just enough fluid and at high enough pressure, and you want to use the least amount of power to do it! On short, yes, a properly designed impeller will help you cool better, and yes, a bigger radiator will CERTAINLY help cool better. BUT, what royally pisses me off is how radiators are marketed as just "bigger".... I should quantify my statement that a "higher energy capacity" radiator will help. You want to know how many fins per inch, how thick, etc, etc. Just more TMI, a radiator's ability to "cool" is really its ability to dissipate heat. Heat is energy. Heat moves from high temp to low temp using variables such as differential temp or dT, and thermal conduction properties. As the air temp goes up, your radiator LOSES how many BTUs it can dissipate. You can either boost the air through it, lower the demand on it, or lower the water temp in it. Example, water temp is running about 200F, air temp is 70F. dT=130F. Riding on a hot day in the sand water is still trying to run about 200F, air is now 110F, dT drops to 90F. That is a big problem when you run the math! You just lost 30% of your cooling capacity! I will stop here for now.

Carb slides are in wrong and you compressed the springs when you put the caps back on. If you look through the back of the carbs, you would see the slides are open. The soft throttle feel was because you were not pulling up the slides because they were already open, and your cable on the top is also because there was no spring tension. Pull slides and get then in the right way and should be good but make sure they still open at the same time or in "sync" Brandon Mull Engineering

Water pump engineering is tricky work to get right, even at static rpms. With a PTO driven pump off of an engine, the pump performance becomes highly variable with rpm. The target flow rates of any proper pumping system employed for thermal transfer is the turbulent flow threshold. However, this flow rate target may only be achieved in certain ports, and the radiator cores may be too small have any appreciable gain from turbulent flow. In short, the radiator cores are purposely designed to limit flow rate based on ideal differential pressures. The theory of "slower water works better" is not supported by any engineering practice. In fact, higher turbulent flow will always perform better. However, there is a point of "diminishing returns" for too much flow rate as this just eats up power to run a pump. I guess I could go on all day about thermal transfer but we helped an aftermarket company design their radiators. They were good at making them, not so good at calculating the thermal exchange. You have to look at the thermal conductivity of the radiator (Aluminum), the fluid, the thermal mass, surface area, air temps, etc, etc. A radiator is just as variable as anything else in the system. What does this jargin boil down to? In the Banshee, we design to ensure the pump does not have significant "slip" which is basically power lost that only generates MORE heat. We target higher operating pressures and proper impeller filling, which will eliminate cavitation. When you look at a pump curve, there is always a pressure/flowrate comparison, and it became obvious that in auto industry, "high flow" seems to be the trendy term(we even use it), but "high pressure" is typically more ideal. Why? I will use just an example. If the stock Banshee pump can do say 2gpm at 0ft of head pressure, that flow rate could drop to a poopy .5gpm at only 10ft of head pressure. So when looking at the "flow rate" of a pump, you must always consider the pressures too. And when it comes down to flow velocity, it doesn't care about pressure, but without pressure(differential pressure really), you cannot get efficient flow across the radiator. Brandon Mull Engineering

Parking brake! There is a switch on the handlebar. If the lever does not fully return, the CDI is in limp mode and will not rev past idle.

I would probably direct folks to Grainger, McMaster, or better yet Digikey and such for proper electrical greases and cleaners HOWEVER, what do I recommend? NOTHING but an aerosol contact cleaner with an oxidation reducer to clean up contacts and simply ensure your connectors are are to snuff. Why no grease? Because Banshees are used in dirt and sand, and the grease will do nothing but collect that crap in the small connectors, then you can never get it out. What I have seen is guys goop this stuff in a connector, the grease becomes contaminated with sand, then they open the connector and "reseat it", in which the sand drives a wedge between the contacts. Lets just say it creates more problems than it solves for many connectors. You might notice several OEMs using grease in multipins but that connector is typically shielded in several other ways including an Oring. The grease mostly functions to eliminate air space. The grease that you find at auto parts stores is silicone typically and was designed to be used on the BOOTS of the plug wires to create a seal between the plug and boot and prevent them from sticking to each other. That should be applied with a small brush or Qtip only.

I have noticed a few posts regarding the use, or misuse of dielectric grease. The term "dielectric" refers to to opposite of "electrically conductive", in which it is actually an insulator!! A common specification used in the electronics industry called "dielectric breakdown" refers to how much voltage per mil thickness a material can insulate before voltage will "leak" through. The common dielectric greases found at auto parts stores are usually a silicone grease. It is called dielectric grease because it can be used AROUND electrical contacts without concerns of voltage carrying through the grease and finding a short. Consider it like a liquid insulator! There are some greases that are designed specifically for multipin connectors and switches with a LOW dielectric breakdown. These greases are formulated to purposely conduct at very low mil thickness (close proximity of a socket/pin connection), but otherwise have high enough dielectric so as not to create shorts through the entire connector. Grease is used to lock out moisture. The reason I bring this up is I notice several people advocating the use of dielectric grease for "all connections", without consideration of what grease is used. In short, the common variety of silicone grease actually has a HIGH dielectric breakdown as it is intended for spark plug boots so if you put that on a metallic connector, you will actually create RESISTANCE, which is opposite of what you want! This can cause all sorts of electrical problems. Now, I realize some tech sheets for spark plug wires may even promote the use of this grease, but their goal and intention is to rely on a high pressure contact to squeeze the grease away from the actual point of contact. And also realize spark plug wires operate at many thousands of volts. Apply that same method to a connector with only 10-15V, and you have effectively installed a resistor in the connector. There are greases formulated as "electrically conductive", and are commonly used in electronics. They are not as common in automotive applications because any accidental overage can create an easy short. The proper use of common silicone dielectric grease would be to apply the grease ONLY on the connector boots to create a high quality water seal, but it should not be applied to the actual metallic contacts. Brandon Mull Engineering