[jamrock876]

A question though, I have been battling an odd issue with my cousin's CG-based engine. The valves, primarily exhaust, repeatedly "get tight" or drop entirely shortly after being properly adjusted. I have checked the pushrods are straight, checked that the timing is correct and the camshaft is within spec.

This all started after the rebuild from the first dropped valve, my working theory is that it is running lean and overheating which leads to the valve stretching and or the seat receding, is this a possibility

I am aiming to have both bikes -CB250 "Hi rev" and my cousin's CG150 "zhujiang"- down today for maintenance and service and would appreciate any input provided.