The Du Bro Truspin is what I use, too. As for Joe's comments on flywheel balancing on his website, I do respect his opinion. However, I have come across at least 3 Ryobi 31cc flywheels and every one of them is off differently. Unless Ryobi purposely "off-balance" every single engine they produce independently - not likely - I would attribute that more to manufacturing vairiances than being purposely engineering that way.

YMMV.