ORIGINAL: 123Cat
I was flabergasted , it has a circular counterweight , no attempt to balance and a really thick piston , it ran OK , but I will try a rebuild , and hope for the best , now can you make a piston from very hard wood ?
I happened to notice this weekend that my Drone engines have unbalanced round crankshafts in them too. I think way back in 1947 and 1948 they weren't particularly interested with engine vibration. So it is hard to say as to how important it really is.
Also the MARZ 2.5cc diesel engines have round unbalanced crankshafts too. At least the ones I have looked at do.
But it was funny to see that the DEEZEL engines all have cutouts for the crankweb in an attempt to balance it better. It is funny that they did the extra machining steps considering that most of the engines don't work.