SlowMoe

I've seen some very very fast 400ex's. Anyway yeah, pull your crank and send it with your jugs. It's only like $75 for the true and weld. Cheap insurance. While you've got it apart you can port match your cases (when you get it back of course) for a couple extra horse, and If you're somewhat mechanically inclined you can cut your transmission for much better shifting (you will be very glad you did this) You can also mod your shift star, add some stiffer clutch springs, mod your timing plate while it's apart, all basically free mods that will help you put that extra power to the ground. There is a DIY on the transmission mod in this forum. Just use the advanced search feature and search easy shift on titles.

Carbs..........................SOLD Pingel.........................SOLD Front shocks................SOLD

That's cool, thanks for looking out. The cylinders, however are legit. I've inspected them and all no worries here.

I was hoping someone could tell me the differences between an 8 plae clutch and a standard. Is the clutch basket different? What about the pressure plate? And there is just 1 extra steel and 1 extra friction, right?

Bingo!!!! More area plus a stronger pulse from the port "popping" open.

You know I don't really know much about sled engines. I'd find out on a sled forum if people are cutting pistons on that particular engine. If it was my engine I'd go for it but I'd hate to cause someone else to jack up their stuff.

That sums it up well.

Sale pending on cylinders Sale pending on front shocks Someone needs these pipes. Similar hp as a shearer but fit 100% better from what I hear. And I know someone needs a solid complete bottom end. I may have a little wiggle room on that one so make me an offer. ^ ^^ ^^^ ^^^^ ^^^^^ ^^^^^^ ^^^^^^^ ^^^^^^^^ ^^^^^^^^^ ^^^^^^^^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^ ^^^

Woohooo! i got one right!

Puzzling. If it was me I would start it up and try spraying starting fluid in one carb then the other and see what effect that has. If it effects one cylinder and not the other that could indicate a problem with one cylinder. Do both pipes get hot when you run it?

Yeah it's pretty sweet except you have ti deal with people like that sloryder cat on occasion but other than that it's pretty groovy

Thanks brother The cylinders are top notch for sure.

If you have compression, fuel and spark, it has to run. I'm sure you didn't put the piston on backwards Maybe try spraying starter fluid in one carb then the other and see what happens But I still believe it's a spark/ timing issue. Not sure if swapping out the wires on the coil would cause an issue...

Front shocks $160 Rear Shaw $160 + 8 Swingarm WITH chain $160 Paddles $190 J-Arm frame $100 plus shipping

So it stopped revving before or after you opened the cases? And you're 100% sure the key is in there? It really sounds like a timing problem.

Picture a piston with 10 feet of stroke inside a cylinder. Now, imagine how fast that piston would be travelling at 60 rpm (1 trip down and back up in one second). Picture how fast it would be moving. 10 feet of stroke one way. Now imagine a cylinder with one mile of stroke at the same rpm (1 trip down and back up in 1 second) The second piston would be moving like ten thousand miles per hour to complete that trip in one second. The first only 20 feet per second average. Piston speed is a big factor that limits high rpm operation in large engines. I think there is a set limit of like 3,000 feet per second maybe that you shouldn't go over. Something like that.

Did it rev the very first time you rode it before you replaced the pistons? Sounds like maybe a timing issue. You sure there is a timing key in there? My 10 mill cheetah had the same problem come to find out the flywheel key was gone. Also your carbs could be out of sync badly?

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Avgas grades are defined primarily by their octane rating. Two ratings are applied to aviation gasolines (the lean mixture rating and the rich mixture rating) which results in a multiple numbering system e.g. Avgas 100/130 (in this case the lean mixture performance rating is 100 and the rich mixture rating is 130). In the past, there were many different grades of aviation gasoline in general use e.g. 80/87, 91/96, 100/130,108/135 and 115/145. However, with decreasing demand these have been rationalised down to one principle grade, Avgas 100/130. (To avoid confusion and to attempt to eliminate errors in handling aviation gasoline, it is common practice to designate the grade by just the lean mixture performance, i.e. Avgas 100/130 becomes Avgas 100). More recently, an additional grade was introduced to allow one fuel to be used in engines originally designed for grades with lower lead contents: this grade is called Avgas 100LL, the LL standing for 'low lead'. Road fuels tend to be measured on a RON scale, for which unleaded fuels tend to be 95 - 98 RON but are only 85 - 87 MON. Avgas is measured on Lean Mixture (similar to MON) but also has a Rich Mixture Octane rating. The Lean Mixture rating is 100 octane (15 octane higher than the comparable 85 MON for unleaded Mogas) but Avgas also has a Rich Mixture rating of 130 which allows higher supercharger boost pressures to be used without detonation occurring. This is particularly a problem when using high power settings at low altitude, for example during take off. Gasoline used for aviation fuel generally has two numbers associated with its octane rating. Examples of this include the (now almost completely unavailable) 80/87 avgas, and the 100/130 avgas. The first number indicates the octane rating of the fuel tested to "aviation lean" standards, which is similar to the Motor Octane Number (MON) rating given to automotive gasoline. The second number indicates the octane rating of the fuel tested to the "aviation rich" standard, which tries to simulate a supercharged condition with a rich mixture, elevated temperatures, and a high manifold pressure. It is obious to me that the mon is 100 or so, which, as said earlier is 4 less than typical race fuel, but it is the 130 rich octane number that catches my attention. I might be way off here, but on a two stroke with an expansion chamber doesn't the engine operate at a simulated supercharged condition which would lean toward the 130 octane rating?

I had originally bought some drag ported cylinders by Dave Morre from this guy on ebay (fullforcepowersports) that he told me were for a stock stroke. Come to find out they were for a 4 mill and i threatened to mess up his 100% feedback rating, so he offered these cylinders off his personal bike and promised me I would not be dissapointed. He said they were done by a good friend of his who goes by the nickname coonie. I spec'd them out and the durations are approximately 198/128, genuine drag specs. Also the quality of the port work is better than any I've seen, they make the Dave Moore cylinders look like garbage, as well as cylinders that I've seen from some of the sponsors here. Not saying they will run better, because pretty ain't fast, but you can tell this guy knew what he was doing when he ported these.

This is a statement I pulled off an aviation forum: 95 Octane sounds only a little lower, but remember, fuels have two octane ratings. A rich octane and a lean octange. 100LL is known as 100/130. Lean octane is 100 and rich is 130. 95 is estimated to be 95/115. So at a lean octange you are only 5 octane lower, and at a rich mixture you are 15 octane (actually performance numbers) lower. So the power setting the aircraft can operate at cruise will be only slightly lower, but the power settings on takeoff might be substantially lower.

Yes, my interest initially was in finding out the effect of using a flat roof, as I had devised a way to modify the piston to cause the port to open at the same time, giing the effect of using a flat roof. Then I began to ponder what other effects this mod would have on the engine, and realized that you could also gain a good amount of mean port area to allow the combustion gasses to escape at the same time, without changing the exhaust duration. I'm just saying that to me you could probably gain a good bit of power if your engine was deficient in blowdown time/area without narrowing the powerband as much as actually cutting the roof higher

Well I had read that avgas 100ll is actually 115 octane, so when i saw a site sponsor selling a used head rechambered for race gas only i asked him if avgas would work, and he said it would. I also told him I heard it was really 115 at sea level and he said that was true. So I told him it was kinda silly to pay 10 bucks a gallon for race fuel when avgas is around 5 bucks. He agreed. That's all that was said. Apparently when you elevate fuel it reduces the octane rating.

I was reassured by a very popular site sponsor that avgas 100LL is 100 octane in the air and 115 octane at sea level.