Thanks Firko, Jonesy is dead right, over carbed and cammed.I have been getting help with the XL500 project from Jeff Hawbaker (a mate of Pat Ormans) who has one of the fastest XL based mtrs in the scene over there, I emailed Jeff about the issues with maybe too much power and he said there is no such thing as too much.Funny thing is with that big carb and cam the engine is still brutal down low, not soft at all and will sit and idle, just has a big rush in the mid range ie too big.