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How much compression?
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Posted by: wvspeedfreak

How much compression should a stock 70cc mini have?

Posted by: bstuart

It varies from machine to machine depending on cylinder and head design. I don't know of very many 70cc 4 strokes so I'm going to assume your talking about a 2 stroke. Generally it takes about 90 to 100 lbs to get one to run. (although I did have an LT80 that started and run for several months at about 80-85 lbs) Most will be between 140-180 lbs when operating normally. I have 90cc race motor that measures about 220lbs. Are you having problems getting one to run?

Posted by: wvspeedfreak

Sorry,I forgot to specify that I was talking about a 2 stroke.I was asking about the compression because I checked our Kasea skyhawk 50 with the airsal 70 kit just out of curiosity and it read 60 psi

It runs awesome so I am sure I am just not getting an acurate reading.I only have an automotive style tester with a fairly long hose and I don't know if that affects the accuracy of the reading on these smaller engines or not.

Posted by: 400ex4ever

When you are testing it you have to turn the fuel off and have someone hold the throttle, wide open while some one kicks it a few times until you get the top psi reading. I would guess the 70 kit should be around 140-180 like posted before....Let us know how it works and your pressure after you try it this way....