Hi. I have recently bought a 1998 cbr600f3 with 33000 miles the previous owner has tried to do the valve clearance his self and obviously done something very wrong. It now runs on 3 cylinders and smells like fuel when it’s running. Is it a case of just re doing the valves or is there a chance the valves themselves will now be damaged. I have the option of another engine but if it’s just a case of re doing all the shims then I will just do that. Thanks in advance for any help

Mike

 

Measure actual valve-clearance in use right now.
The numbers will tell you what needs to be done next

 

A couple things to add.
when shimming the valves, it’s better to error on the side of loose. The valves will tighten the tolerances over time due to wear.

Adjusting by the valves is the first step In syncing the carbs. That might be the next step