GS 550 '79 - low compression on one cylinder after sitting 2 years

[BadBillyB]

A motor sitting this long can get rust on the valve faces and seats. More so on valves/seats that are open when sitting. A completely closed valve may have little or none. After riding 50 or so miles, recheck clearances and see if they come down. The clearances you have will not harm the motor at all. Rust on a valve and seat will cause the clearances to be high......Billy

[Stigy]

Great thanks Billy. That's a very useful tip. I'm going to check if this kind of problem occurred. Worth remembering for the future.