G1 Compression test.
 

OK. I did a compression test on my newly troublesome 1982 G1 today. It read right at 90 sometimes and sometimes around 85. Will replacing the crank seals better this reading or must I also do a ring job??? Mike

Re: G1 Compression test.
 

Crank seals will not affect your compression reading. Looks like you need to tear it down and check rings/piston/cylinder. I would do the seals at the same time to prevent a lean running condition that would burn up your new parts.

Re: G1 Compression test.
 

Messed with the G1 enough with no positive results. The cart ended up running well, briefly, then slowing way down as soon as it started warming up. Finally took it to a cart shop and they cleaned up the carb, said the reed valves were OK, and said the exhaust damper was stuck shut. They cleaned it up and wired the exhaust damper open. The cart runs much better and maintains when it's warmed up. I know I am approaching a rebuild but it should get me through the season. Thanks for everyone's help. Mike

Re: G1 Compression test.
 

A true compression test is done with the engine at operating temp and the throttle tied wide open. Running the test cold will always net an incorrect reading.
To test if rings are worn excessively, put a teaspoon of oil into the cylinder and roll it over again. If the reading gets higher, your rings are worn.

Re: G1 Compression test.
 

And 2 strokes really need a good cylinder/rings to run well. Blowby will kill power in them much more than a 4 stroke. Of course 4 strokes also tend to have more rings to start with plus a full intake/exhaust stroke.