Low compression.

[Anonymous]

My '80 GS1000G has 27,000 miles on it. I bought after it had been sitting for years. Put 4000 miles on it since. I had a compression check done, and #2 & #3 are low, almost out of spec. That was 3000 miles ago. Checked the valve clearances this weekend, and it is still in spec.

Thinking it's time to pull the head and check the condition of the valves & bore. Could it just need honing & new rings, or are new pistons also in order? I see that Wiseco offers a 1085 kit, but I'd rather keep everything stock. If the valves or seats look questionable, I'll ship the head off. Any good shops in the Orange County area?

[Poot]

did you see whether or not it was the valves or piston rings that needed attention?

27k miles is still pretty young for a GS engine, unless the living crap has been beaten out of it.


use that test where you put a teaspoon (roughly) of oil in after you do an initial compression test.

if the reading goes lower, its your valves that need refurbishing (possibly a valve lapping job?) and if it goes higher, its the piston rings.


poot

[Anonymous]

Haven't wet vs. dry compression test, or pulled the head. I'll rent a compression gauge, and post results. That's fairly low mileage for the bike.

[Anonymous]

Have you checked the valve clearances? I would do that before thinking about major work. The clearance gets tighter as the valves and seats wear and this can reduce compression. At 27K miles, it's probably time for some new shims.

[Anonymous]

I'd run it until it dies. This is one of those things that you shouldn't check unless you are trouble shooting an ongoing problem.

Cheers, Steve