Valve issue on 05 crf450r

[redrider769]

Valves were so out of whack the bike wouldn't even start, measured, calculated, reshimmed, now the bike starts but it backfires big time. Everytime you let off the throttle, there is a series of backfires. Did I install to big of shims? Which ones, exhaust or intake? How often should a person rering and piston? HELP

 

[Rich Rohrich]

You might have the cam one tooth off, but it doesn't really matter in the end. The valves are worn out so it's time to take it apart for a fresh valve job, new springs and new valves.