02-29-2024, 04:37 AM
(02-27-2024, 04:43 AM)m in sc_imp Wrote: piece of advice no one asked for, but its useful. Valves will tighten up , not loosen up on these bikes as miles go on (typically unless theres a mechnical failure). an early indicator of this is loss of compression on one (or more) cylinder. a down and dirty check is a warm engine compression check on all 4 cyls. if one is lower than the others beyond the allowable range, (20-30 psi i would guess) good bet that cyl needs a valve/shim adjustment. (if all else is ok). .02
@m in sc
Please correct if I say anything dumb or (partially) wrong.
If deposits built up between the valve and the valve seat, that valve can no longer return to its design position. That entails indeeed a loss in compression - gas is able to escape when the valve is in the closed position. But in this scenario the distance between valve stem end and cam has increased. The opposite of “tighten up”.