ORIGINAL: juanes1969

Ok guys, I have a problem with excesive vibration from this engine. I will try to explain my set up and thing I have tried in order to fix this:
The engine turns a mejzlik 26x10 at 6700 rpms. I leaned the low needle until I got good transition and steady idle.
Lawn boy Ashless 40:1. Only 9 flights thru it. About 3/4 gallons.
The low needle was turned right and left, trying to get rid of the vibration, the idle changed and the transition to full was bad... the vibration was still there.
the same was done with the high needle to no avail.
The spark plug was medium brown in color, but I still changed it and the vibration was still there.

I know that a single cylinder engine has more vibration that a twin, but I`ve had other singles that don`t vibrate to the point that it takes things apart inside the plane. (DA50, ZDZ50, ZDZ80RV) these are relatively smooth engines.
I was thinking that the factory timing might be the problem. but in the 3Ws the prop hub has two magnets and the meassurements for seting it are made in degrees. Is there a simple way I can set the timing right using milimeters?
If you guys think that there is more to it than the timming, please let me now as I`m running out of ideas.
Any advice?

John