blowit

You really need to verify that your comp gauge is working correctly. I have seen a lot of senseless rebuilds over a junk gauge. Always mic the cylinders and pistons that come out to verify what you have. As for the water pump, might I toot our horn there. We provide our max flow pump and billet drive gear to put an end to water pump issues. www.mullengineering.com Brandon Mull Engineering

What I mention above is that you would NOT be losing strength or toughness of the gear but you would be losing wear resistance due to the loss of the case surface layer. We ran some tests a while back on Banshee trans gears and their case was as expected, I think .010" or so.

Just to offer consideration for cutting gears and the respect to heat treatments, what has to be considered is both the temperature in the cut (not overall temp) and the fact that these gears will have a majority "case harden" on them for structural reasons. The temperatures in a cut regardless if using coolant can well reach outside the annealing and tempering temperatures of steel. It would be unlikely that the entire gear would reach a critical temp but anything you cut almost certainly would have lost some hardness, mostly because the gears are either carburized or induction hardened at only case thicknesses. Case thickness will usually be measured in thousandths of an inch so it does not take much to breach the "crispy crust" Gears are VERY picky about material condition. Most are through treated to bring the metal to a specific hardness and strength, are tempered to further improve the "toughness", then cased to further increase the hardness of the surface layer to increase wear resistance. Any time you cut on a gear, you should really consider a full retreatment of the gear. I understand that does not always happen but something to consider I guess. Brandon Mull Engineering

Very much depends what what flavor we are doing but our head work starts at 85 bucks.

Your specified removal amount does not seem unreasonable depending on other factors. However, we only provide full rechambering of the head to include machining of the gasket surface and combustion chambers. Decking the head will help but rechambering is the only way to do it right in our opinion. Brandon Mull Engineering

Well, there is a natural tendency for the impeller to push out towards the cover when running. And, the lubricity of Ethylene Glycol is mostly sufficient to buffer large impeller wear on the back. The main issue IMO is the tolerances and the impeller depth being somewhat dependent on the clutch cover. IMO, the whole system should be held captive in the clutch cover. I guess if I were to design it, I would likely use a fork/key drive in the end of the PTO shaft thus run 1:1 with the crank, eliminate the gear all together, and design a pump that uses a mechanical seal with a nut on the shaft to pull the impeller tight in the housing and against the seal. that is all well and good but I doubt anyone would spend the 400 bucks it would take as a conversion kit with new design clutch cover.

Sorry to keep anyone waiting. Had some other contractual obligations but have another machine now dedicated to our off road division.

Mike, I would be real curious to learn more about a failed billet pump. They will certainly fail if other foreign objects get run through the system though. Anything would fail. One of the main concerns with the plastic pump is overheat protection. Plastic looses strength DRASTICALLY over 200F. I have seen motors pushed to 230F which is enough to kill a plastic pump. We don't like to see engines that hot but it does happen more than people think in trails where there is little air flow. I do agree though that the OEM design is very poor, allowing the pump to float in the housing. Look at a Honda if you want to see a properly designed pump. They don't use plastic either!

There are three things that will overheat a bearing, excessive force, excessive rpm, and grease. I know a lot of people recommend greasing the hell out of bearings but it is a fact that more grease causes a bearing to run hot. I agree with above that bearings are bearings....within their rating class though. The higher the precision class, the faster the rating BUT the better the mating housing and shaft need to be to take advantage of that. All that being said, at 70MPH, a 22" tire would be spinning a massive 90rpm! Even the shittiest of bearings with about any grease could do this as long as there is not excessive force on the bearings from misalignment.

We finally have another batch of pumps available. For those that are not familiar, we noticed some rather poor designs on the market that were proven in testing to flow less than the OEM pump. We redesigned a new pump using the latest computational fluid dynamics software. We originally offered this pump as a press on to the OEM shaft because the OEM shaft is actually BETTER than the shafts on other pumps which are usually stainless steel on nowhere near hard enough to work well as a long life shaft. Due to customer demand, we have now provided an integral shaft with our pump. And, as usual, we had to raise the bar. We are using a carefully selected steel alloy, tool hardened, ground, and ceramic lube coated to provide outstanding wear life and improved seal life. The shaft is over 3X harder than comparable stainless shafts. We found several pumps over the past few years that were leaking into the case due to a huge groove being worn into the stainless shaft and losing contact with the seal. We seem to have lost one of our call lists with a recent server upgrade so if we miss you, I apologize. You can find the pump here. http://www.mullengineering.com/sc/store.php/products/yamaha-banshee-yfz-rz-billet-waterpump-water-pump-impeller-drag-race-radiator-online-444 Thanks Brandon Mull Engineering

http://www.mullengineering.com/sc/store.php/products/yamaha-banshee-big-mouth-venturi-intake-kit-filter-outerwear-big-bore-carb-stroker-drag-online This is all I can offer. Our intake was designed for improved performance over just pods but also clears the frame and pipes without issue. Sorry, we do not have an installed pic. I have also seen people make shields to protect the filters. Brandon Mull Engineering

The life of a bearing is largely dependent on the shaft and bore in which they mount. If the spindle in question is damaged, it may (most likely) distort the inner bearing race when mounted and cause premature bearing failure. The bearing was designed with a certain interference fit in mind. If that fit is not retained, the inner clearances in the bearing are not taken up. Guess you can try it and see what happens but I would get it back off as soon as it starts to fail again so you don't spin the race on the shaft and make more work for yourself.

Wiseco or otherwise forged pistons are neither concentric or cylindrical. You are inspecting the clearance at the timing edge which will certainly be more than other places on the piston. I too would recommend that someone mic the cylinders and pistons to determine the actual clearance. It is normal to see some wiggle on the top. The amount should be measured.

He was referring to a crank operated power valve rod. You do not have powervalves on the Banshee engine. If you still cannot get the head off, pull the 8 cylinder base nuts and remove the cylinders as a pair.

Yep. Do you have the slides in right? They can be reversed right to left which makes the chamfer on the bottom point towards engine. You want them towards the filters. Also TRIPLE check the pilots. I lost count of how many we have fixed. They are tiny and plug easily and they pretty much will not run without.

the emulsion tube is an easy remove/clean/install. Since you messed with the needle/seat, you now have me wondering if the bowls are filling up at all. better check into that. The screw on the bottom of carb is a drain. Float level is likely a non-issue here. Choke are plungers. Need to move freely, and no damage to cross tube that connects them.

Soaking will probably not do much good. If you found restriction in the jets, clean them out and run it. Should take 30min to fix this. Also verify the choke plungers are working correctly. One pulls the other via vacuum

Your compression (or relative reading from the gauge used) seems low if cylinders are not ported. However, the primary mode of intake function is crankcase vacuum when the piston is going up. In short, the compression does not largely affect fuel draw as much as ring seal and piston clearance. The very first thing I would do is verify you have a schrader valve in the tip of the test gauge insert used. I would also recommend you clean the carbs and/or add some raw fuel to the intake to confirm it wants to run. If it fires up with fuel added, get the carb apart and start there. Inspect the pilots first.

You usually do not need to rejet for compression changes but the compression does affect timing due to burn rates changes. At your elevation, you will be safe running 18cc domes and a little timing. We do not have any pics of the intake system installed unfortunately. I will have to see about mocking some up on a bike since we have had others interested in that.

You are on the right track by considering raising the compression ratio for your elevation. I would also add that as the air density decreases due to your elevation, Intake modifications really become paramount for decent power. You just cannot get enough air in the engine. Intake porting, high flow reeds, carbs, or even our intake kit will all help you considerably without sacrificing anything on engine life. Brandon Mull Engineering

I apologize if my previous post sounded ass-ish. If you prefer an Al trans, we can certainly do it for you if that is what you would like. It will not hold the power you are requesting but we can make it.

We can machine an Aluminum trans for you. I can approximate it to hold 20HP and last about 100hrs. Hopefully that helps.

For stock to lower power builds with low maint, ProX For heavy hitting builds, Wiseco. X is a casted piston, will be more dense, have more uniform thermal expansion, and higher silica content which equates to longer life but slightly more brittle. Wiseco is forged which IS the best way to go for tough applications because forged bends rather than breaks BUT because they are basically "stretched", their thermal expansion is all over the map, thus causing accelerated wear and require more bore clearance. The biggest problem with cast among Banshee guys is sticking them in a hole that is too big. That will kill them quick.

As mentioned above, a damaged clutch assy that fails to fully disengage can certainly cause your issues. If you can pull the clutch and roll the bike when in gear with it off, it is likely OK. Adjustment of the shift shaft assures that the shaft returns to "home" position correctly but does not change the amount of force applied to the shift cam. This is a typical symptom of bent shift forks or shafts. Typically they shift well in some areas but there is a particular shift that is difficult or impossible. The best you can do is inspect all components under the clutch cover, including the clutch, then plan to open the trans to inspect further. I will note that we have seen clutch packs with shattered friction plates exhibit these issues in which they might seem OK at idle, but the higher the rpm, the higher the centrifugal forces in the clutch.

Um, I am not going ass deep in this conversation. Just noticed our name in the thread and making sure we did not do something wrong. Couple things for consideration, above mention was 3 tenths. 3 tenths really is 3/10 or .300 of whatever, most likely an inch here. However, in us machinist terms, real tenths is a friggin MILE so most know that when we refer to "tenths", it is actually ten thousands of an inch of .0001". Not trying to make anyone right or wrong, just offering perspective. Regarding checking a crank, the crank would (or should) be tested for both radial and axial runout or "TIR" (total indicated runout). This is basically the wobble of the crank shaft from true dead nuts. There is also the phasing of the crank that is totally separate from the above in which the max stroke from each rod is measured relative to the crank rotation. The banshee should be 180* phasing but those angles can also be calculated into linear measurement with trig. It is very common to see a Banshee crank twist or lose proper phasing which just results in poor performance. It can usually be determined by only testing the the true TDC of each cylinder with a precision degree wheel installed. Anyway, probably more than is needed here but just trying to clear up any confusion there.