At what rpm is it going flat?
You should be max rpm in the mid 8000. (8400 to be exact)
It may be a clutching problem then.
Old Cat Rider
'93 Wildcat 700EFI w/ Comet 108 Pro-4 clutch & 01 ZR skid
we are all given sh*t in life, but some of us learn to turn it into fertilizer and grow from it, and some us try to fling it on others like monkeys