You can always run a compression test on your engine and see if it falls within factory specs. If the compression is out of specs, maybe you want to see about doing your top end, if you are still in specs, unless you are at the bottom end of the specs, just ride it and have fun. You can always check your compression every month or 2, it's pretty easy to do, you just need a compression tester with the right threaded adapter to fit your spark plug hole. The tester will usually come with directions. You can get really cheap ones at harbor freight or you can always check Sears for better quality units or maybe you know a buddy or mechanic that can check it out for you.
Nicholson 500x (Project)
Nicholson 185s
Nicholson 110 (That takes an atc70 tank)
Ascott 500 head/350x (Project)
Homebuilt Racer Chromoly Suspension 110 (Ragin Runt)
PK Racing Suspension 70
A+ Inc Suspension 70
AWS Aluminum 90 frame
Hi Performance ATC Suspension frame rd350
Hi Performance ATC Suspension frame 90