Here is my understanding of 2 stroke crankshaft balance factors...

I have used these theorys for adjusting crankshaft balance for 2 stroke racing motorcycle engines. They apply equally to r/c engines.

The best way to support the crank, is like Edward said. Being that the crank has only one side journal, there is no other practical way. His way should get you very close.

In my experience, I have had the best luck with balance factors between 58-62%. It's amazing how much difference the engine runs with different balance factors. But like most 2 stroke modifications, nothing is written in stone. It's always a trial and error game.

On the other hand, 4 stroke singles, balance well between 48-54%. Go figure!!

Here is a simple diagram for my technique that may help you guys visualize the balance process.

The formula is very simple: B/A=%

where A= approx 1/2 the rod weight + the piston + the piston pin + the piston pin clips

where B= The weight of A (Piston assy, and 1/2 rod)counteracted by the crankshaft counterbalance weight

where %=the resulting balance factor

Hope this helps!!

BK