Ok so now my Elite is acting exactly like Ken11s. It will not do 50 mph. I tried the new gasket, which did pretty much nothing. It has no power now, and it runs like crap. I could easily get on my Honda 50 and smoke it. I have put a Ridiculous amount of cash into this bike, totaling around $2,000+, ranging from a whole new engine, new gaskets, manifolds ETC. This thing has really never run quite right, but now it is worse than ever. It does exactly what kens does at 50 mph. I can fix a lot of things on this scooter, but this is a major problem. It just feels like the tire locks up at 50, and then it slows down to around 25 and sours back to 50. The new gasket, however, eliminated the backfiring, but it still does this. You can list basic things all day, but I have checked them all. I know the fuel is good, it has a brand new carb, the valves are adjusted right, the gaskets are all new and so on. The brakes are also fine, the gear reduction box has fresh oil and it keeps doing this. I have spent a ton of hours on this, and nothing seems to help. I can also put it on the center stand and floor it, and at no speed will it do anything unusual. The only thing I could even possibly consider being a problem is the transmission. I have briefly looked it over, but I did not see anything out of place. The engine, like I said, has recently been replaced do to the old engine loosing compression and failing, and only has like 2000 something miles on it, so I don't see what could cause this. Another thing, it once in a while runs great and will do 50 for a short time and accelerate like a real 150 cc, but it rarely does this anymore. It used to run like this for a while, but it just quit and does this now. But when it does this, I can here a funny little noise from the engine, like lightly tapping rocks on the road, and it will accelerate great and hit 50, but then about 10 seconds in it will mess up and not run like this for a while. I am about ready to junk or sell the bike, as it has never ran quite right. I would Appreciate any suggestions on what to check out or what could be a problem.