Yes I have an airplane but I use auto fuel regular in the plane.
You should be able to bump the compression all the way up to 14 to 1 I think with methanol the problem with methanol is your engine will be a fuel hog and the alcohol is rough on the aluminum parts, alcohol will draw water out of the air, will cause rust on the iron parts in the engine if left for any length of time and not ran.
I'm not sure just what a guy would want to do on getting the compression way up there I'm very happy with using regular gas and not mess with the higher octane stuff its more expensive.
I haven't got wild with the compression either just a few thousands taken out to raise the comp. not more than 0.050 so far.I can't decide what I want to mess with next I've been having fun making the pipes and might get a little more involved but still not sure the pipes are a lot of work to make.

Milegajo
What size main jet did you try I went up to a 0.080 I think and still seems a little lean you must be pretty lean if you have to use the choke to make it run, I messed with a mix of 2parts reg gas with 1part methanol and I used castor oil at a 32to 1 ratio in the mix castor will mix with gas or alcohol. I didn't like the results all that well and quit messing with blends wish I still had access to some nitro as I like to play with it makes engines go real fast before they melt down.

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