Question for Eric on Cylinder Head Milling

[carrollcw]

Eric,
It has been brought to my attention that you are an expert on the effects of milling a cylinder head on my old 84 CR500. I had the head milled due to some compression was leaking from the head because there was an indentation on it letting some leak. Within a few hours of riding, I screwed up the rings. I've heard these bikes already run hot and that could have made it worse. Do you think that it could be the problem? If so, what do I do to fix it? Thanks.

 

[EricGorr]

Milling the head implies that the volume of the combustion chamber will be reduced and the compression ratio raised. That engine needs a lower compression ratio, achieved by narrowing the squishband and widening the combustion bowl.