On a frsh top end , yes. My second over build on the stand, full of assembly lube, no carbs got a 165 psi reading. My 750 kitted engine set up the same way was 195 psi.
On an engine with a few miles the compression can be a bit lower. The book calls for a 145 psi minimum reading on a good engine. within 10 percent between cylinders.
If there is a lot of carbon build up the reading can be higher. The extra carbon build up makes the combustion chamber smaller, this raises the compression ratio.
So your reading is not unbelievable.
If you think you have a carbon build up take the air filters off With it running spray diesel fuel in the carbs, Keeping the rpms up a bit . After 30 to 45 seconds stop adding the deisel. Let it set for awhile. 24 hours is good. Now restart the engine, do the same with water you did with deisel.
You might want to remove the exhast when you do this. You might plug the mufflers.
Useing the deisel and ltting it soak soften the carbon build up. The water breaks up the carbon and it gets blowed out of the engine.
Retest your compression. It may or may not change.
Testing the cimpression on a regular basis can help you spot problems before they ge to bad.
Leo
Leo
