I did the following checks;
- Removed the rocker and checked for any visible problems. No dramatic wear issues and valve collets looks to be seated correctly.
- Measured valve spring between valve spring seat and valve washer at bottom. 6th cylinder exhaust measured 44.48mm and 3rd cylinder exhaust measured 43.50mm as a comparison, so valve on 6th cylinder certainly is higher therefore why my adjuster is screwed right down.
- Measured the compression ratio, 155psi average across cylinders. So I’m not down on compression on the 6th cylinder.
All I can think of now is:
- Valve seat is receding or was cut deeper (but I don’t seem to have a compression issue to indicate the valve seat is worn.
- Valve stem has stretch.
Has anyone got any other thoughts what the issue could be and if I’m running any serious risk running the motor in this condition?
Thanks for your help in advance. :-\