Head gasket and compression

[LoHo]

I've been working on a basket case for some time. I am reluctant to sink any real money into it until I have some prospect of success. I have done a valve job on it and adjusted the valve lash back to specs. The cylinders, pistons, and rings all looked good. Because I was being cheap until I saw some daylight, I re-used the old head gasket, which was not exactly in "like new" condition. Now the compression is a uniform 50-60 across the four cylinders, and the "drops of oil in the cylinder" doesn't change it. Does this indicate a leaking head gasket? The consistency makes me think so, but I'd like some consensus before spending.

Otherwise, I'll just repaint the gas tank again...

[XJOK2PLAY]

Sounds to me like that's what you got...

Should be anywhere from 130 to 155 I'd think.

You might try a leakdown test... but 50 lbs. of compression's not good.

Only other thing if not head gasket might be valves leaking, bent... something like that, but wouldn't be affecting all 4 cylinders...

I'd pull it and clean it all up good, change it out w/ new gasket. IMHO

[bikerphil]

the compression is a uniform 50-60 across the four cylinders

If the carbs are on the engine already, the throttle must be held wide open. Closed throttle will give low readings. JAT

[trbig]

I have re-used head gaskets multiple times with no ill effects. If you had a leaking head gasket, you would have a leak on one cylinder, not all four uniformely.

The fact that the compression readings didn't increase with oil in the cylinders indicates the rings aren't a problem. As stated, for a correct reading, you'll need the carbs wide open, a warmed up motor, and a fully charged battery.


Tod