80cc cylinder upgrade kills engine will not run


New Member
Feb 11, 2021
Hello everyone I am trying to figure out I bought a JRL head high compression for my 80cc so I replace the piston rings cylinder cover and a high compression head from Amazon come to find out the Piston was hitting the cylinder cover I added an extra gasket and it seems like fixed it i had compression I had Spark carburetors good but it will not run I replace the Magneto and the CDI box I have constant Spark so I put the original cylinder sleeve and head back on with the new piston and rings and a different carburetor Magneto and coil has been replaced brand new spark plug brand new wires this thing will not run I was told that because the cylinder head and everything that my engine might be toast any suggestions I've been working on it for 3 days off and on and I could have rebuilt this thing by now y I am a mechanic but I'm still kind of new to two stroke bike motors thanks for any suggestions and everybody stay safe

Larry Trotter

Active Member
Nov 26, 2017
Surprised no body answered you. Are the new and old pistons the same? Are the ports in the cylinders in about the same place? Have you made it run yet?