An engine from a parts bike I bought has a cylinder with enlarged exhaust ports.  I estimate they are about 30 - 40% larger than stock and the porting work seems to have been done very carefully.  The ports are very smooth and symetrical.  After getting the crank redone and replacing the coil, I got the engine running on a test stand set up but can't tell much about the power it may produce.   I know from go-kart work I did many years ago, porting can be easily over done.  Short of putting it on a bike to check it out, does anyone have a feel how the servi-cycle engine should respond to exhaust porting?

This is a photo of the 1941 Servi Cycle I owned way back when.  My parents bought it for me in about 1949.  It had an H model engine and was the subject of many paint jobs and mods.  Looks like a rat rod even by the standards of the day.

Hi all, my name is Milt and my affair with Servi Cycles started when I was 14 in 1951 after my family bought me a 1941 model for $25.  It was a push start model but had an H model engine.  I rode around the streets of Bryan, Texas on that trusty Servi for many years.  Unfortunately my younger brother gave it away while I was in the USAF.  About 12 years ago, I bought a basket case to restore and a couple of years later bought another basket case.  The first one has been running for several years now but was never fully restored because I let my grandchildren ride it while they were young.  I now plan on finishing the restoration of first one and have begun work on the second one.  BTW,  after the first Servi Cycle project, I completely restored a James ML.  I have a few pictures I can share of my various projects when I find out how to post pics.  I'm looking forward to interacting on the forum.