blowit

No, a polished look is not what you want. polished means lack of oil retention. We add crosshatching to cylinders to increase oil retention. It would be important to hone the cylinders at a minimum (add cross hatching). Vertical stridations in the bore can be numerous things but usually comes from over heating or FOD damage. Mull Engineering

No, adding oil will not make it shift but if you ran it low on oil, it is possible that something has seized. OTOH, it sounds more like the typical shift claw has jumped off of the shift star. We mfg a star with longer pins that fixes it if that is what is causing your problem. Have to pull the side cover off and star there. http://www.mullengineering.com/sc/store.php/products/yamaha-banshee-yfz-rz-billet-shift-star-shaft-drum-transmission-race-drag-sand-shifting-hard-online Mull Engineering

Without writing a novel, most casted pistons are a hypereutectic variety with a high level of silica with will result in undisolved solids in the grain structure. This silica improves scuff resistance while also being harder than Al but does give up some ductility. These levels of silca are not found in forging alloys. Also, comparing forging to cast, a cast piston will have a tighter, more uniform grain structure while the forged piston grain is "stretched" into form so it is constantly under stress. Forging is actually a good thing for many structural applications but the down side in a high delta T situation is irregular expansion during heating. This can cause increase scuffing and requires additional clearance that further accelerates wear. I am NOT dogging the forged piston and they are usually preferred for HO applications but they are not the best for all situations. A forged piston can last a long time as well. However, you may see in increase in skirt heating from increase blow by, irregular ring wear, etc. All things that we accept in the quest for performance. Hypereutectic pistons have evolved greatly with new alloying and do much better in a high mileage engine such as a car. Brandon

No and No. I would highly recommend leaving the stockers in. Just no reason for Wisecos. Forged pistons also are a softer material (less silica) thus they will wear more. It is not uncommon to get a couple hundred hours or more from stock pistons. B

We do not currently have them on the market. We are redesigning a few things to make them easier for users to install/adjust them. No word on when they will be back. We have been slammed in the shop lately. B

Sure sounds like jetting or carb sync from here. Check carb sync and make sure jets are clear. B

We sell a slick intake kit if you are looking to go to pods. Ours will outflow most anything out there. http://www.mullengineering.com/sc/store.php/products/yamaha-banshee-big-mouth-venturi-intake-kit-filter-outerwear-big-bore-carb-stroker-drag-online Mull Engineering

I'll throw a 5 on it that the stator is fine. fix that wire and go ride... B

Post a pic of the damage. as long as it did not get into the coated coil wire, you can easily save it. Show me where it is screwed up and let's go from there. The only place it "might" hit is at the back and that area is easily fixed.

And what do I win... Good to hear to got things going. Enjoy. Mull Engineering

X2, you probably sheared the key. I have never been able to keep a flywheel on without either torquing it or zapping it with an impact. Brandon

I guess I assumed you pulled the clutch cover, then slide the shaft out (very easy), then removed the seal. Either way, it sure sounds like to pushed the shaft out a bit and it went back in the wrong position. Just have to remove the cover and see what is up. Bad news for you but this one will teach ya to check shifting every time you mess with a motor. We test shifting several times during a motor build to detect any assy problems because they cost too much time.. B

It is likely that you did not get the return spring centered on the spring shaft for the shift shaft. When you removed the shaft, it did not go back in correctly. Probably time to pull that cover and find your problem. B

I would first recommend adding to your original post rather than starting a new one. Sounds like you should start by inspecting your reeds. Pull the carbs, then the reed blocks, take close pics, and post them up so I can help you. Thanks Brandon

No, the nut is not LH thread, but the puller is. You can certainly go find a nut to get you going but remember to install a washer under it. To say that all nuts are the same, that is not really the case. Many different fits, pitches, etc. Brandon

That is most likely lean pop. Take LH carb apart again and focus on ONLY one jet, the pilot jet. They are commonly cleaned incorrectly and they must be absolutely cleaned out to work right. Brandon

One of the common misconceptions of the OE Banshee head is it causes over heating. This was built up by the key builder of the billet coolhead 20 yrs ago. It does NOT cause over heating but I will admit that in stock form, the head does not burn correctly thus causing more localized heating in the head. I will write a tech article soon on the subject but basically because the burn rate is low, this causes more heating in the head. If you increase the burn rate through optimizing the combustion process, you reduce the localized heating in the head. I will not, however, say that increases in the CR will not increase heating because it will but that is true with any head. I will also say that we have been able to take a stock Banshee, shoot the CR through the roof, keep it on pump fuels, AND reduce over all engine temps through careful engineering of the combustion and heating processes. You really have to study the areas where the heat comes. The bikes we did that on were trail type bikes that were subject to major heat loads but I will admit that they did cost money and many Banshees are getting built on a budget today so we do not really advertise those services. Mull Engineering

You seem competent enough to do the job. Just remember that 2 pokes like to taper because of the all the holes in the cylinder so you may spend more time at one end than the other. Chamfer is critical and probably the most over looked aspect of an 2 poke and a high ranker in my rebuild customer list. I guess if you miss it, you will have to skills to do it over. I will admit that there are plenty of crazies, that know nothing about engines, boring 2 pokes and putting on a half ass chamfer and getting away with it. If you plant to rebuild every year, it might not matter. Most of our motors run for many years though. We just do NOT agree with the "break in like you are going to run it" theories. Engines that are new have higher CF factors (coefficient of friction) than run in motors. That friction translates to heat and must be carefully monitored if you want an engine to last. Hot metal will melt, cause glazing, glazing causes poor lubrication from lack of oil retention, and the cycle continues. Where I am going with that is cylinder finish. It is rather important on a 2-poke since you do not get near the lubrication compared to that of a 4 poke with pressurized oil, oil rings, etc, not to mention a MUCH smaller piston surface area. Mull Engineering

That is an odd one. Make sure to have a pic or two of your problems. I would like to see what is causing your issue. B

If you cannot get the star to move in either direction, you have other issues. Make sure the detent arm on the side moves like it should. Also look over by the front sprocket and find the Al soft plug in the case that is about 3/8" in diam. If you have a pin working its way out of there, you have a problem. Sounds like something might have gave up in the trans but thought telling from here. Was there an event that started this situation? Start it without oil??

I would highly recommend finding a reliable engine tuner that can look at your bike. To be honest, you may spend more on engine parts than a tuner will charge to properly set it up and explain what is going on. Also, we will rarely setup a Methanol bike for anyone unless they are very experienced with tuning. Reasons are that Eth and Meth require nearly constant attention to jetting due to the chemical composition of the fuel. It may also be that your engine was not jetted properly or a jet is clogged. There is a long list of possibilities but getting the right answers is key. Let us know where you are and I am sure someone will know of a local shop to you. Mull Engineering

http://www.mullengineering.com/sc/store.php/products/yamaha-banshee-yfz-rz-billet-shift-star-shaft-drum-transmission-race-drag-sand-shifting-hard-online Our longer engagement pins on our star correct most of these problems.

Simply shaving the head instead of properly rechambering will leave horsepower and efficiency on the table. We have several guys that have went from a shaved head to ours with great results. I will admit that it can be tough for us to schedule in just 1 head at times but we have cut hundreds of heads over the years and not one dissatisfied customer. Just a thought.. Mull Engineering

If you asked me before, I probably told you to rev it up and drop it into gear. Rev just enough so the bike will take the gear without dying. Then get rolling and pull in the clutch. If the clutch does not break adhesion at that point, there is a problem. It is common for plates to stick from time to time. start with new trans oil too. That will help. B

You certainly either have a water pump failure or the o-ring and seal where the output coolant tube goes through the case is leaking. However, that should not keep your clutch from engaging at all. Or is it NOT disengaging. I really could not tell by your post what the symptom really is with your clutch. B