I use the one I make from clear tube and a yard stick, all said and done it costs me less than $10 to make. Add a small ball valve to the bottom of the loop and you can control it so nothing gets sucked into the engine. I use 2 stroke oil in it so even if it does it won't hurt anything. cheap balancer This is very accurate, possibly too accurate.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!