Originally Posted by
av8tor1977
My twin cylinder (boxer style) engines are so silky smooth it is amazing.
That is an encouraging report. In the fullness of time, I might be saving up to buy myself one. Would have to assess the size required, possible the 120 cc DA.
Vibration as severe as you describe is totally unacceptable and may be contributing to your running/tuning problems. Your prop hub may not be true, or your crank may be bent or twisted.
AV8TOR
The vibration is most severe at idle. When run up mid to high RPM, it is much less severe and almost acceptable. Accordingly, I have concluded that it is not a balance problem. This may be wrong though.