Just bought a new fancy digital compression tester and cold front cylinder is 139 and the rear is 150. Pretty close to whats acceptable but I will check the valves and make sure they are correct. When hot, what would be acceptable? 74 flh, New topend.

randy

 

Every motor is different. The important thing is that the cylinders should be within 10% of each other. Yours falls in that spec. It is outlined in your factory service manual on how to do a proper compression check.

 

3 pumps on the gage is what we use with a small battery charger in place