Compression ?


New member
I just bought a clone on here it's a ksr supposedly with 3races on it it starts ok and seems to run on stand ok but it seems to not have much compression I have a fishel that has what seems to be really good compression is it difference in builders? or do you think the 3 race old clone maybe has more than 3 races ?? Any thoughts ? Thanks
Take the valve cover off both of them and put your finger on the end of the exhaust rocker, roll the engines over and see if you can detect a compression release. The cam will barely bump the exhaust open at slow speed on the compression stroke. I have watched great salesman hawk their engines by comparing effort to pull the cord compared to another engine. It is simple to take the decompressor off, we used to do it we thought it was the right thing to do.
Do they have the same camshafts....and, timing could be set differently as well. A leak-down test could be of help also.....jmo
By "not much compression", do you mean as you feel it by the pull rope? And if so, is it more noticable when engine is cold versus when engine is hot? If so, it could very well be intended to be this way.