Help XBR build problem

[JOOLZ]

I have the crankshaft installed in the left hand case, went to fit the balancer and it doesnt fit, the gears are different, something I didnt know I thought all parts were interchangable, confused can anyone clarify, havent seen anything on the net about it. So now looking for an xl600 balancer and another set of bearings

The balancer turned up today, still waiting for the bearings, hope they arrive before Christmas, oddly the xl600 balancer is heavier than the original xbr item

[welland99]

Unexpected problems can be very tiresome, but it sounds like you have a solution. 

Why is it unexpected that the xl600 balancer is heavier than the XBR item?  Wouldn't it need to be heavier to counter the greater weight of the larger piston?  (assuming that the xl600 piston is larger, and thus heavier than an XBR piston)

[JOOLZ]

I found an easy solution I turned down the balancer shaft by 1mm, all fits now. I realise the 600 piston is heavier than the 500 piston but not by that much. my bike was smoother with the Wiseco 600 piston than it was with the standard 500 piston.
The crankshaft counterweight for the XL600 is quite a bit lighter than the XBR crank so maybe that is factored into the balancer weight