blowit

Evil, we might be interested if you have a pile of good heads. Not trying to get step on toes and we can probably work something out with the OP. We are out of decent heads around here. Really prefer to buy several at a time. Brandon Mull Engineering

Working on a couple things but what are you looking for? It is hard for us to invest time in something that is already being done though.

Thought I would let you guys know up here, I just posted in the sponsor section of our Summer Sale on select water pump and shifting products for the Banshee. 10% off all goodies for limited time!

We are having our first ever Summer Sale on limited products for a limited time! Select products include our water pumps, water pump drive gears, shift stars, and detent roller mod kits. 10% off all purchases! Only available through our website directly. Don't miss out!! www.mullengineering.com/sc/store.php

I just wanted to clarify a few things, trying not to come off as a dick here. 4140 (not 41/40) technically is chromoly which is just a term given to some 4000 class steels due to the inclusion of Chromium and molybdenum. It is not tool steel, but rather a high tensile structural steel. 4000 series steels have a wide range of conditions and each condition will give different structural characteristics. I am pretty surprised to see one groove out like that though. Agreed though, corners without a radii is a structural no-no. However, that does not seem to be the failure point on these baskets. I am wondering what plate clearance is being used. Brandon Mull Engineering

Good to hear it. Sometimes no news is good news in this business!

Indicating the flywheel has nothing to do with lapping the seating surfaces.

And you indicated the flywheel in?

There is a bushing that rides between the seal and crank behind the gears. That bushing has an Oring on it. At least pull all that stuff out, inspect the bushing and the seal. Blowing that much smoke you likely popped something, either case seal or crank seal. woops, just saw that it passed a leakdown. Is it possible that your fuel and oil was separating? Probably a long shot though. You would certainly smell the case oil as much different than 2 stroker oil.

My reply must have went poof. Do a std leaddown and if right side fails, block all but one vent for the crankcase so you can hear the air escape just to confirm where it is going. If the clutch cover is off, you may be able to hear the air leak past the seal. vents are also at the back of the crankcase. Grease on the seal is always recommended and certainly did not cause your issues. There is an oring on the seal spacer that could be an issue as well.

I would highly recommend you indicate the mounted flywheel axially and radially to check for runout. It appears the other one was welding itself which can be caused by excessive out of balance or not mounted correctly. I had one in here some time ago from a member that was fighting with broken cranks from this issue. Worth checking! Brandon Mull Engineering

Sort of rare just due to the rib on the crank seals but I have had one pop out. I would recommend a leak down on that side and plug your vents to see if you can detect the any air leakage on the vents. I suspect if things went that bad it will likely be an easy find. I have also had a couple engines in where the cases did not seal up right. Brandon Mull Engineering

Not sure what "bowl height" you are referring to but it is very common to get fuel leaking past the needle/seat. If you are sure the float is installed right, just turn the fuel off, use the drain screw to drain some fuel on that carb, and turn fuel back on. Sometimes something gets in the needle/seat and won't seal. Have to get the pressure off of it.

LOL

My point was not to prove anyone right or wrong, but get the wheels turning to how compression, piston speed, and timing are related. One hint though is due to the changing parameters, flame front propagation is also variable unlike what some think.

Anyway you want to dice it, an engine compresses air, then pisses fuel on it. The principals are exactly the same whether utilizing reverse cone reflection wave exhaust technology, precompression methods with positive displacement or centrifugal pumping. The point worth taking home is how air compresses. Atomized fuel does change a few things but nothing that latent heat and fluid dynamics cannot predict.

An air leak in the engine is very highly suspect then. I would recommend a leakdown test on the engine at this point. You have blown out a crank seal or something.

UCCR, CCR, air density, timing, peak rpm, engine use, air temp, fuel, head geometry, squish clearance, etc. Some have trouble relating torque and HP. There is a very specific reason that timing advance rolls off with RPM and head work has a HUGE effect on required timing. Let me further add that an engine is nothing but an air compressor. When we look at bare bones industrial air compressors, why is the compressed air in the volume tank MUCH hotter than it went in? Why is piston speed, compressor RPM, or rate of compression a very analyzed value in the design? Why air/air heat exchangers after the compression cycle? These elementary gas law principles can help predict what is being discussed here.

I don' think you will find your problem in the coil. Test results sound normal. you do have bran new plugs, right? I have made that mistake before.

popcorn in hand.......

Look the procedure up in the manual available on this forum.

If your problems are throttle position related, only on one cylinder, you need to look at carb sync and likely the pilot jet in the left carb. To quickly look at sync, raise slides until the mark is showing in the glass window on the side of the carbs. Adjust the tops. However, if it was fine before, you might have the cable a little screwed up that is causingthis. The "Y" in the cable is a common place for issues. If you find the sync is fine, you probably need to clean the pilot jet on that carb. No, the stator would not be your issue. However, if this is plug wire/cab related, you can swap plug wires side to side and see if the problem stays on the left. I would guess you have a carb issue, not spark. Brandon Mull Engineering

^^^ agreed! We just repaired one for a guy last week with this issue. The shift shaft spring has a pin that it centers on. That pin is eccentrically ground so as you turn it the shift claw moves up and down. Claw must be centered over the shift star or no shifty.

Nope. Jetting is NOT your issue. I have no idea why we are looking at jet sizes, elevation, etc. You have an acute failure somewhere. I can't do anymore to help you though. If you truly are not getting fuel, you will have to find the reason or take it somewhere that can.

You need to send the cylinders to someone competent to tell you what will work with them. You don't just "bolt up" another crank. Port timing will be radically affected. That is what makes turd bikes. You need to know what you have. If it was trenched, it might be setup for a 10mm, you don;t know. As far as compression, again, cranking compression does not mean a thing!!!! I have some of my MX motors out there with 250psi of cranking compression!!