what is the compression ratio on a 400ex, also what brand of hi comp piston would you reccomend? how hard would it be to install? what other kinds of mods would I have to do? thanks for you input

 

The stock compression ratio on the 400EX is 9:1.I've heard that the JE 11:1 high compression piston is a good setup.My dad put a 440 big bore kit on his.About the hardest two parts are timing it and getting the rings compressed enough so that you can get the piston into the cylinder.
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