Balancing props may be a waste of time on small single cylinder engines. Most of them are not completely balanced internally, so having the heavy blade on the counterbalance side of the crankshaft may make the engine run smoother.

The story > I am at a Formula One race, on the line warming up the engine and adjusting the needle valve during a racing heat. My engine (ST X-40) is running at around 21.5 K when it throws part of a blade. The engine picks up to 22.5 K and is running very smooth. So I race it. Engine ran great, viberation normal, and I cut 4 seconds off the best time that particular airplane had ever ran for a heat time. The blade that had come apart was half gone. It was a grain flaw in the wood that caused the blade at the hub to be full width, while the blade at the tip was only a sharp point. This prop was way out of balance, yet on the engine ran smooth.

On an electric, it is a good idea to balance, but on single cylinder internal combustion? Maybe not.