blowit

I think that is a rarity. I would check your meter and testing methods first. As well, for a quick test on the stator source coil, you can go steal a 5-10w bulb from your kids night light and hook to red and green wires from stator. Should light when kicking. Coils are known to have termination issues right at coil. remove the plastic clip at the coil, pull both wires straight out and test the pins in the coil. Then cut about 1/8" off wires to get a nice new termination. Don't break the plastic clip. Secondary is plug wire to plug wire. Brandon Mull Engineering

CAM, we have looked into the shifting components in depth and agree, the core issue is a needed complete redesign of the shifting system!!! However, as you mention, there are likely not enough bucks to justify going through all that. We basically would have to start from scratch. I can't (actually I can, I used to work for them) believe Yamaha never corrected all the minor issues surrounding the Banshee engine. All the rein in the 90s and they did not reinvest.... No wonder Yamaha dumped all their design engineers and started over at the end of the 90s. R1/R6, Raptors, YFZ, YZ-F. Knowing this thread is treading on my area of expertise, I will say a LOT more goes into making an actual production part than just CMM'ing someone else's part, and machining a few. You really do have to look at the whole gamut such as inventories, shipping, customer service, liability, component failures, materials, processes, structural fatigue, etc. All I can say is customer service, failures, and "does it really work" are at the top of our list. I could probably go on and on between the differences in engineers and machinists. I have had to get in the middle of engineers and machinists in one of the biggest aerospace companies in the world. Engineers know what their computer says will work, per the numbers. But then they do dumb shit like a .0625 radius at the floor of a 6" deep pocket! Machinist don't understand why we want a radius in the first place! They also 'rarely' understand material properties enough to know how to get started from scratch, only bitch that the programming is wrong..... Machinists don't fully understand WHY that endmill will chatter, but they know from experience that 3/8"diam, 6"LOC cutter is not going to work. Take Ti for instance. I have in depth knowledge of the material and know WHY it is a bitch it cut. The word WHY is what I preach to people. That is the foundation of understanding. Actually, most engineers may know the properties of Ti, but fail to relate it to machining. What sucks is the actual properties that make Ti such a great material for high fatigue locations, especially landing gear, is the same properties that makes it suck to cut. OK, I am just rambling I think.... Brandon Mull Engineering

If you are referring to the soldered termination posts, about the only thing that would cause that is poor contact. In the electric world, we are all about the current and resistance. If you have a poor contact, that increases resistance, which increases heat, which causes things to burn. Vibration can also cause solder joint cracking, which leads again to high resistance. If that is indeed the case, that is certainly an assembly problem. Post pics. I would be curious to see this. What I suspect is the coated coil wires are not being bared before soldering which would make for a very poor contact. It is important to use an acid or other methods to bare the coil wire before soldering to the post.

The basic components are the stator ignition coil, stator lighting coil, and pulse coil. These are all discrete circuits. By reading, I am assuming the ignition stator coil is opening after riding? It is not very likely that something else is "causing it". The magnetic flux generated at the stator is fixed and very minimal. The actual current flow is low. Voltage is approx 80-100VAC single phase. That power is just being rectified in the CDI. What would be most common is use of inferior coil wire with a poor lacquer coating that fails with heat. Need to know if the resistance of the coil goes higher, lower, or open when failed? Now if you are somehow leaking the lighting side power to the ignition side, that could cause problems and roast wires but it most likely would not run at all. Brandon Mull Engineering

IMO, sidestep the "SS" (aka, ramped crown) pistons. They don't add 8hp and they do cause issues with squish in the head chamber. Ramping was typically done as an R&D technique only, before more porting was done. Not normal to "have porting" and have those ramped pistons in there. You might want to share more details and get some measurements on the cylinder to know what durations you have. As far as pistons, likely any will work fine for you but we typically recommend a casted piston over a forged like Wiseco for mild builds. The higher silica content in the pistons gives them better wear characteristics and more uniform thermal expansion to resist cold seizures. Brandon Mull Engineering

Few things 1. make sure carb slides are in correctly. cut away on bottom goes towards filters. 2. Make sure they are synced. Usually when you pull carbs, cables get moved around and gets off. 3. You need to use the air screws for pilot level adjust. You can typically adjust about 1 pilot size through the range of air screw adj. This will also help tell you if you are getting close. 4. Most of my engines are on 25-27.5 pilots. Helps keep them cleaned out. Brandon Mull Engineering

Plastics are indeed used in engines. I am not sold on the idea though. The physics of plastic breakdown with age, heat, and oil intrusion is well documented. There is a finite life of plastics in that environment! Vibration and cavitation in this application also apply. HOWEVER, it is never wise to assume an OEM does not know what they are doing. The impeller certainly can make contact with the housing if tolerances are not working out. OEMs have much looser tolerances and Yamaha does not have the time to personally "fit" each pump so it does not make contact. Personally, I feel the whole design is a little out dated as the mechanical seal and aluminum impeller is a much more robust design such as Suzuki and Honda like to use. A few ways in which our pump improves things is due to the material, we can open up the vanes to pump more water per rev. We also designed it "tighter" than OEM as any gaps actually cause a loss of efficiency. We also intentionally leave a small nub at the center of the back so if contact is made on the back, it is a very small point, not the whole back side! We always recommend completely fitting the pump on the clutch cover and testing for contact but those issues are very scarce. Our shaft should meet and exceed OEM spec for strength and wear resistance. We thoroughly tested all of them. It is approx 3X harder on the surface than the comparable stainless designs. They do this because they can just order ground rods and cut and go. We actually have to make them, surface treat them, then grind them, then apply our friction coatings. But it makes for a better product. One question I might have for the OP in this case is if the bike was being ridden when over heated? Remember that you must have air movement across any water/air exchanger to get heat transfer to the air. Some will be radiant but air flow is a must. Brandon Mull Engineering

Gravel is correct. We recommend when using the burp bottle to just run the level at the minimum. Filling up the burp bottle will always result in coolant burping from the bottle. If tank is emptying completely and the level in the radiator goes down, then you will need to investigate further. Water/glycol mix (coolant) will not really expand much at all BUT engines will always generate steam pockets in the coolant system. This steam will seek to escape through the radiator vents. The burp tank acts as a condensate tank allowing the steam to recondense in the burb tank. Brandon Mull Engineering

I might be of some help here being a bearing guy. Might be easier to just email me. First thing to do is determine how the bearings failed? Exploded? melted? Those types of bearings fail usually for 3 different reasons assuming you stay within engineered margins. That is FOD (foreign object damage), too much axial force, roundness. If you are getting something in the bearing, the balls will be very dull looking with damage in the races. Axial force will show in the races as hot on the axial contact points. Roundness is a BIG deal and commonly overlooked. Both the inner shaft and outer race housing must have roundness and size to the spec of the bearing. Otherwise heat buildup will kill it. Imagine those balls having to constantly squash and deform to an irregular race clearance. This is similar to a tire....flattens out on the bottom where it makes contact. The right thing to do is clamp up the cases to torque spec and have a machine shop check the bore diameters for size and roundness. The half ass way is to clamp just that one bearing in the race and spin it to see if it feels right. I have seen perfect bearings destroyed in seconds because the race housing is out of round. They will make noise too. You may have oiling issues too that will cause heating. Examine the oiling holes and path. Brandon Mull Engineering

Just to clarify, factory heads do not cause overheating and any such claims cannot be met with any credible or quantitative data to support the claim. In our experience in cutting the OEM Banshee heads for the last decade or more, the cut or dimensions make big difference in how much heat transfers to the engine and how much goes into the exhaust. Factory Banshee heads are all Aluminum. It should be worth noting that Yamaha deleted the primary cooling passage and primary source of heat!.... The exhaust port! They stuck a plug in the bottom and called it a day! We never did commercially offer "just a trim" on the stock heads for a reason. If you are going to take the time and effort to cut the factory head, please do it right and improve it while you are there. I don't believe we ever had a call to say our head work did nothing to improve performance. However, we have never just "shaved" a head for a customer so that might not be a good comparison. Brandon Mull Engineering

I think a lot here might be pretty depressed to see how many big names rebadge China tools. Mitutoyo, Fowler, Starrett, and even bigger specialty tool names. Sad but true.... BTW, when I recommend a China bore gauge, it is not that I intend it to be used as an accurate tool. engine bore mic'ing 101 is about transferring any reading to the micrometer so only one tool is doing the reading. What I mean here is get whatever value you find on the bore gauge, then transfer that to the mic. If we needed a real value for the bores, not just a reference, there would be no way I would EVER accept a replaceable anvil device for this in our quality system. What I like about these little gauges is I can easily determine out of round and taper to qualify if a bore is worth measuring. In a quality system, it is more about tracability to a certified standard. If we are measuring a feature of 1.0001, we would qualify a tool with a certified standard of 1.0000.

But doesn't smell as nice! Can't put a value on smelling good!

Well, lets not veer too far into antifreeze properties of propylene glycol (opposed to ethylene) typically used in radiant systems. I firmly believe most systems can be much better optimized and protected with proper water analysis and treatment! The only thing P.G. brings to the party is antifreeze protection. The best example I can think of so far is electrolysis in a hot water heater! Anyone ever replace an anode rod? these are special Aluminum rods in about every water tank which allows the water something to "chew on", rather than your tank. You can only imagine what it will do to an Aluminum engine. We can dive into chemistry real fast here but to stay with KISS principle, use antifreeze or wetter in your water. Do NOT use high hardness tap water. Anyone ever see what happens to a fired heat exchanger like a tankless water heater?

I would just add that the crosshatching in cylinders is actually VERY important as it aids in oil retention. We rarely tear an engine down and not at least hone it to renew crosshatching. If you are new to this, do some reading on it and tune your hone speed and cycles to get the correct angle of crosshatch. I have seen a LOT of guys (even at the dealership) just grab the drill and spin her up to max and hone like a wild man. You will actually run these pretty low speed.

I would not recommend mixing the water wetter and anti-freeze. Choose one or the other. Wetter is basically minus the Ethylene Glycol so you will not have freeze protection. If cooling is your primary goal, I would use Wetter. I should also mention that there are still some recommendations from coolant OEMs for distilled water. This is in effort to drive a baseline for their additive package. It is easier than saying "use water with a PH of 5.5-6.0 and total hardness of 20ppm or less". With exotic materials being used in engines today, coolants become even more specialized, thus the reason for some OEMs specifying certain coolants only. I am probably over complicating this for a Banshee though!

Right on!! I will add to this. Water has a higher specific heat than Ethelyne Glycol (coolant) so water would be a superior coolant. HOWEVER, distilled water has now been proven to be very volatile by itself! Why? Distilled water is water that goes through a distillation process that removes most trace minerals. H2O by itself has a strong affinity for minerals! What does this mean? Distilled water without minerals will actually eat your engine up trying to replace minerals. Coolant is actually a VERY scientific product, as much as oils. There are PH buffers, mineral packages, corrosion inhibitors, etc, to satisfy the water so it is stable in the engine. Case and point, There was a rash of tractor engines that were eating their cylinder liners and Orings. This was caused by a "lack" of minerals or depletion of minerals over time. The cure for this is actually a replaceable coolant filter that has a saturated media with trace minerals and buffers built in to leach these minerals back into the coolant. This keeps the coolant stable. Water is also actually acidic thus the reason for PH buffers to correct some of this. In short, water by itself can get you home but I never recommend it long term, even in an Aluminum engine. We also now use mineralized water for coolant mixtures, not distilled. Distilled is usually acceptable when blending with coolant because the coolant has the properties to correct it. What you don't want is high hardness water with high Iron, Manganese, or Phosphorus. Basically water wetter is a blend of minerals, buffers, and lubricants, in higher concentration so more water can be used in the ratio thus "better cooling". We used to think of water as "inert" but it is actually anything but..... Brandon Mull Engineering EDIT: I poked around online for a useful link for reading but I am finding that STILL, most people are in the dark on this! I see quotes that distilled has a PH of 7, etc. I will remind of a couple points. Distilled is a weak acid. We use acids for electrolysis (plating, etc, transfer of elements from anode to cathode). You MUST have as close to a neutral PH as possible and a mineral package in the water so it is stable. Another example I remembered is radiant floor tubing systems. Used to be thought that the best for this is distilled....WRONG. It will eat up fittings like crazy.

You will have to let me know how that works out. I cannot remember, were you running closed loop? We tuned a few engines on E85 but quit because guys were constantly out of tune due to variables in fuel from the pump. Does not take much ratio change to cause issues with tuning. Hell, I think we fight less with Methanol than E85.

I always recommend a ground strap on the Banshee due to very poor grounding. There is a ground from the stator but has connectors that are subject to high resistance over time. You do not need to go nuts here, a simple piece of 12ga wire from engine to clean chassis ground will do fine. I have personally never agreed with carrying ground through a steel chassis but many OEMs do to save $3.... Trailers are notorious for this.... And people are constantly chasing ground issues because of it... Steel is NOT a quality conductor. Copper is your friend. Brandon Mull Engineering

I would recommend if you are buying anything, first buy a 2-6" telescopic bore gauge, and a mic set. Even the China ones will do just fine for this. Then you can be sure what you have. Anything less will be guessing. You can probably own all this for $150 bucks and have the ability to check any other bores in the future. I have personally bored a few engines with nothing more than a 3 stone hone in a pinch, but I don't recommend that unless you know the tricks. You can screw this up pretty quick. Final finish should be done with a 240-280 grill ball hone which will help smooth the port openings, BUT you still need to do a proper port chamfer.

I tend to disagree with the "just bore it" sentiment. The main reason so many Banshees are on their last bore. Only bore if it is needed! the only way to know is to have it properly measured by a machine shop. I look for things like a ridge at TDC from the rings, taper, oval, and overall dimensions. We draft a worksheet for bores to determine all this. It might not seem a big deal if you are at a low bore but what if you blow it and need several bore sizes to clean up the bore? Never bore unless required. All the numbers you need are in the manual. Brandon Mull Engineering

may end up redoing the leak down. May not have got cases fully seated to each other and blew the sealant out. In any case, the retest should tell you lots in terms of what is going on. If it is not lean run-on, you need to make sure the carb slides are actually returning to the bottom. You should hear them tap the idle screws. Common on a rebuild to have the cables bound up somewhere and slides hang up. Slides are a must check every time you mess with the carbs. Brandon Mull Engineering

Thanks for the kind words guys! Always appreciate knowing we are meeting our customer service needs. Sometimes we just have to assume no news is good news! Prepping to hit the dunes for Waynoka Snake Hunt 2015 as I type. Brandon Mull Engineering

Guaranteed, that is how we would approach it but I also have to consider what options people consider "mandatory". In the CNC world, I still find it ridiculous there are things like "tool changer option" available on production machines.... I am going to explore some rather simple base model functionality just to see what it will take. What I am looking at here are things like ambient temp, pressure, etc. These are things that can be built into a dyno BUT, IMO, you could run down to wally and get a little China weather station, manuall input the data in your run, and record it. After all, none of those functions are going to dictate what we see as performance numbers from a run, they only help in certain calculations to determine AFR, EGT, etc. Don't get me wrong though, IMO, doing any sort of dyno work without recording all the present conditions can lead to unexplainable repeatability issues.