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15:1 is just asking to lean seize the motor. I know some of the manuals recommend this but it is not necessary at all and a big risk. Next thing I would look at - what type of honing are you doing? You may be creating an improper cross hatch pattern or excess piston clearance. Are you measuring the piston and bore precisely after the hone? I suspect there may be something odd going on with your testing method. Most little 2-stroke engines will not want to kick start when the compression numbers get that low and will need to...

Well , i personally dont own any yz85s at the moment but i would not be running 15:1 ( lean actually) regardless what anyone told me or what i read somewhere.... I will leave it at that because there will be alot of opinions on this.... 3 heat cycles riding the bike or on the stand in the garage? Seating the rings is so important at initial start up and to perform this properly you need to put a load on the motor , ie; riding the bike . Higher oil content (15:1) could actually prevent initial seat. Maybe youve...