ORIGINAL: Sport_Pilot
The only problem I have with high compression engines is that they are more difficult to idle slow and shake more. This because if the increased resistance during the compression stroke.
My experience has been different. When I raised the comp on an Enya 60X from the standard 9.75 to 13.5:1 to make the most of zero nitro fuel I found I had to lean out the idle mix drastically and it then idled much slower and very steadily.