I could weigh the piston in grams or ounces to see what it weighs. How does one figure what it should weigh for good balance? I got another 25cc Homelite engine with stock flywheel. I think I will run that with exact conditions to see how much it vibrates. I got 2 more engines I got to run also. It may be some time before I try to balance the 25cc I have been running. Dave.... Thanks for all the Ideas. Capt,n