Piston Kit & Engine Balance??

[wheatdog]

General question concerning GS 1100 overbore kits. What happens to the crankshaft balance when someone puts an overbore top end on the engine without taking the whole thing down and having the crank rebalanced. Unless the new pisons & rings weigh out pretty close to the stock ones begin replaced, I would think it would put the whole setup pretty far off. For an engine that tachs to 9500 that could cause some serious vibration.

Mike

[tkent02]

It's not as critical as it might seem, as long as all the new pistons weigh the same. The two inboard pistons going up counterbalance the two outboard ones going down, they are 180 degrees apart, net result is the same. There might be some slight increase in vibration, but nothing like what a thumper, an inline twin or a V twin would get with the same piston weight change.

Still, I will try to lighten my 650 pistons close to what the 550 ones weigh before they go in the 550.

Most important is that they are all four the same weight.

[Nessism]

Nope. Only thing that's important is to make sure all the pistons weigh the same...which will be the case with just about any decent piston kit so no worry.

[SqDancerLynn1]

AND a roller bearing crank can not be re balanced