blowit

I would love to share my opinion of RM but will refrain... I will agree that Chariot's plate seems a much better value than the casted ones. They are easy to strip and screw up...

NOt sure if you were aware but we do make a billet drive gear so that does not happen again... http://www.mullengineering.com/sc/store.php/products/yamaha-banshee-billet-water-pump-drive-gear-impeller-drag-race-sand-trail-power-online That plastic gear failure is rather common. Mull Engineering

Before jumping to conclusions, you may want to try another tester or check your test method. http://mullengineering.com/rt/files/2_tech_docs/THE%20TRUTH%20ABOUT%20COMPRESSION%20TESTING.pdf Here is a linky to something I wrote a while back. I should probably add to it but have not had time.

The word for the day is "density". Everyone is obsessed with CR, CCR, etc, and do not take into account that this is a compression ratio but "what" are we really compressing and does it really start at ambient pressures?? There is also the effects of latent heating that certainly must be considered and relate directly to the density.. B

What am I guessing on?? You seem to want to ruffle my feathers with nearly every reply. Did you want to step outside.. I don't quite see what I am guessing on. Thousands of Banshees through the shop here, worked with plenty, yet to have one blow up on me. Personally owned a stocker wtih 19cc domes and 4* on pump. I beat the piss out of it. By doing the numbers, I am not really guessing..... B

I never mentioned a thing about the CR going up with porting, I simply stated that it changes the game. Reasons are that without knowing the durations, we would have no clue as to the CCR thus the fuel requirement. Why would a ported engine require more octane with the same CR? The effects of reverse wave gas flow in the exhaust of course.... This acts as more of a super charger at certain rpms (on the pipe) and stuffs A/F mixture back into the engine. Obviously if the window of time is open longer, more of the A/F mixture can be shoved back in there. This will NOT increase the static CR but WILL increase the "dynamic" CR which is something we look at very closely when designing engine components, heads, porting maps, etc. The "Japanese" method of testing the CCR is called such because it was innovated in Japan and it is a valid test indeed and still has huge considerations when selecting fuels, spark timings, etc. Hopefully that answers your questions. Regarding the 19cc dome on a stock port engine. Yes, pump fuels have been well proven in our shop to work, even with 4* of timing. I am making a few assumptions of the OP's engine but I will spit ball a .040"" squish clearance, 50% squish, etc. I was not really looking at the pumping numbers because that is not very relative as mentioned and really should pump up 170-180psi at sea level but a junk gauge can cause you problems and still not not change the fuel requirements. I have no idea how many engines we have had here that were comp tested "low" by the owner only to find out that they are fine when tested correctly with a good gauge. I am not trying to beat on bike owners but rather stating how things can be thrown out of context by simple using the magic "comp" number as the rule for rebuilding an engine. Other factors must be considered. I have seen pistons that were cracked, falling apart, rings worn out, and they still pump up good numbers. B

Yep, that gear sticks to the shaft commonly and the new part you get will have a better designed bearing on it because of all the problems with that gear. Failure mode is lack of lubrication. Might post a pic of the rod. I have seen many that discolor and run for years. Do your inspections and determine if it is in spec and go from there.

The CR is always the right way to select a proper fuel but since the OP indicated stock porting, I know pretty much where he is at. If he had porting, this would all be a guess without knowing some durations...

You are fine to add +4* with pump fuels on that setup. Probably could push a little more but would have to watch for detonation.

91 octane or above. Mull Engineering

I am not sure what scratch you are talking about but I do not see anything concerning - at least in the pic other than they are rather glazed and need a good hone before putting them back in service. Mull Engineering

As I previously suggested, you may want to pin the powervalves shut or all the way down so you can concentrate on your tuning without the addition of power valve tuning. Removing them all together will NOT work. You either have to pin them in the open or closed position. The problem is that as the valves open and close, it changes the required jetting so you are playing with jetting AND PV tuning. I have every confidence that you need stiffer springs in the PVs so they will stay shut longer but you also need to dial your jetting. One thing at a time... Brandon

Ball park is 260 main, middle position on needles, 22.5 pilots (stock), 1.5 turns on air screws. Make SURE that your throttle slides are not in backwards. The cutaway on the bottom goes to the back of the carb. Also check your carb balance or sync. That bites people a lot.... Mull Engineering

The TORS black box is located just above the LH pipe. Make sure that is unplugged. If so, maybe it is possible that you do not have any idle air set into the carbs. If you eleminate the TORS system, you are supposed to add the idle air screws on the side to adjust idle. If you do not have those, the bike will not idle. We set some bikes up with no idle for racing so it offers more engine braking. Just FYI. Mull Engineering

TORS system. Read up on it here. Make sure your throttle cable is adjusted to allow 1/4" of play in the thumb throttle. If there is either no slack or excessive slack, stalling will occur at a 0% throttle condition. Mull Engineering

I really think you need to have an experienced engine guy look at it. It is normal to experience some binding when trying to test on a bench because this is a constant mesh sequential transmission. They need to be running and rolling to shift good. To be honest myself as well as many other professional builder may have been able to figure out what you had without opening the cases. At least now you will know what you have. I have seen cracked gears on a few bikes and it takes a seasoned eye to find things like that. I am not sure where you are at but if you want ot come see me in KS, I would be more than happy to find your problem for free. There are probably other builders here that can help you but you need to get this to a pro or you might be pulling your hair out trying to find the prob. Mull Engineering

Porting can cause a variance in pumping compression.

Does it run good??

I prefer chocolate chip please. You will probably be best off to remove the sensor all together. IIRO, if you just unplug it problem solved. Not a real super design... B

Sure sounds like the parking brake rev limiter. If you used your parking brake recently, it bites people all the time. Make sure that little lever on the clutch perch returns all the way. If not, it will induce a rev limit and the bike will not rev. Mull Engineering

No, that is what I was trying to say above. The opening of say a 38mm carb is actually pushing 60mm. We have to be looking at how much room is in there for us to get the proper designed venturi in there. As of now, we have two designs for the bigger carbs but nothing produced as of yet. The ones we offer on the site are for stock carbs only. By the way, did you get our banner and able to get it posted? Hoping those files would work.

We have not found time to do any back to back dyno testing but our math, flow bench, and ass dyno shows various gains (2-5HP) depending on what we are comparing to. The big key on the venturi system is the negative pressure which induces better vaporization of fuel and more fuel drawn in. We did our flow tests with a complete assy of carbs and filters. I wish we had more room to do this on big carbs but we have to stay within certain parameters to make it work right and that would make the big end of the tube much too big to fit in the chassis. We may develop another solution soon but just have to see.

Very worth while to remove the flywheel and make sure the key has not sheared. It will spark all day long but never run if the timing is a mile off from a sheared key. We see it a lot after a fresh stator change. Mull Engineering

Jetting, compression, and reeds are things to look at. I just could not say your symptoms are indicative of electrical issues. They will typically show up at random and as soon as the bike is warm. Also make sure your exhaust silencers are not falling apart. That can cause a restriction that will not allow fresh air intake. Remove air filters when it will not start. Also a good idea to check compression unless you are 100% sure it is good. Anything over 110PSI should start for you. Mull Engineering

Sure sounds like you have a jetting issue. A warmer bike will be richer and your pilot seems it may be a tad big. I would try leaning our the bottom end a bit and see how that does. 25 pilot, 2 turns open on the air screws, etc. Does the bike start without choke when cold?? If it starts easily and doesn't't act lean when you first start it, it may be flooding with a warm start. Mull Engineering