Easy compression boost
I had a problem with a new replacement cylinder which was just over 1mm taller than the old. It came from a new factory so I am guessing that the head was 1mm shorter to compensate however I am stuck with my old head for now. Anyway I found a solution which has boosted compression to beyond my old cylinder.
Firstly I did away with the head gasket altogether! To achieve this I took the advice from some knowledgeable members here and used wen n dry glass paper to shave down both the head and cylinder where the gasket goes. To achieve a flat surface put a sheet of paper on flat glass and then using water gently rub the surface holding flat and firm. I shaved both surfaces flat and then using progressively finer grades of paper got these surfaces smooth as can be. This creates enough of a seal to do away with the head gasket thus boosting compression by making the combustion chamber smaller.
The second thing I did which I don't recommend unless somebody has the same problem was to do away with the bottom cylinder gasket acheiveing the same result of boosting compression. My bike now eats hills for breakfast