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Low compression
Posted: Sun Sep 23, 2012 1:22 pm
by zerolander
My first post because I'm baffled. New rings with piston diameters within service tolerances. I can only get about 40 psi compression. Piston and new rings are very snug in the bore. I've been told to check crank seals, oil pump, and crankcase for leaks. I'm baffled because that last inch of piston stroke should be the only factor affecting compression. By the way the crank seals are good. I have used soapy water around the head to cylinder and cylinder to crankcase seals. No bubbles why cranking it over. I checked my pressure gase with an air compressor - it's good. Thanks
Re: Low compression
Posted: Sun Sep 23, 2012 3:09 pm
by fastplastic
Try the oil trick which is to add a few drops and retest compression also remember to hold throttle wide open when texting and to kick till the needle stops moving
Re: Low compression
Posted: Sun Sep 23, 2012 3:35 pm
by Pete M
Are you sure your guage is accurate?
Re: Low compression
Posted: Sun Sep 23, 2012 5:03 pm
by fastplastic
I have a feeling he is taking the test as if it was a four stroke
Re: Low compression
Posted: Tue Sep 25, 2012 3:16 pm
by r2dillon
Is compression testing different for a single cylinder?
Re: Low compression
Posted: Tue Sep 25, 2012 3:20 pm
by Pete M
For a four stroke you use your index finger and for a 2 stroke you use your thumb
Re: Low compression
Posted: Tue Sep 25, 2012 11:16 pm
by fastplastic
All that using ur fingers does is test to see if there is a ring left in the motor not accurate enough to tell u if u have enough to run or not
Re: Low compression
Posted: Tue Sep 25, 2012 11:33 pm
by abreen89