72' cb350 Compression Loss, Help!

[excess11]

I have a 72' cb350 and have lost compression in the right hand cylinder. The left cylinder has 165lbs but the right has only 95lbs are there any typical problems with these engines that would cause this. I think it is the valves,I can hear a faint pop from the exhaust on the right. I do not notice any great amount of blow-by from the engine breather tube so I think that the rings are not the problem.

[Geezer]

Squirt in about 1/2 ounce of motor oil in the low cylinder and test it again. If the compression comes way up then it's the rings. If there is little to no difference, it's the valves.

Also make sure the carb on the low cylinder is opening properly a stuck slide or stuck butterfly valve with give you a false low reading.

Geezer

[excess11]

Poor compression

Thanks for the advice, I added oil and the compression went way up, beyond normal even, So I think that I have trouble with the rings. Now I need to tear it down to see what I got wrong inside

[ratbyk]

Compression Rise

If you had such a dramatic rise in compression the question comes to mind. How much oil did you put in the cylinder.?A small squirt with an oil can. Spin it over a couple of times to distribute the oil then repeat the compression test. Make sur that you are holding the throttle wide open while testing.
Ken/Sooke

[Geezer]

I agree with Ratbyk on this one. You probably put in too much oil. One stroke on a pump oil can is about 1/2 ounce and just about the right amount.

Kive it a few good kicks with the plugs out to clear the cylinders then check again.

Geezer