Hi Guys,

            New to forum so hello to all, I am building a 650 engine and putting it into a 500 frame.  I am lightening the reciprocating parts and crank to suit. I have the 500cc engine and the 650, so I will carefully weigh all the parts before I go any further.  I am hoping to get close to the 500#'s with the new and modified 650 parts. I have done this work  on other bikes successfully in the past, just not with the added complication of the balance shafts.
      My question is, if I take a proportional approach to this, can I re-balance the now lightened parts balance shafts to suit.  I have nerve damage in my right hand and cannot handle the excess vibration, dead hand no brakes. Are these shafts optimised for a particular frequency to suit the frame or done to a formula to offset the secondary forces.
      I would appreciate hearing from anyone who has rebalanced the assembly including the balance shafts before.
      I will be statically balancing this to start with, followed by dynamic  balancing, and reducing friction on shaft balancer journal surfaces. So I am hoping to account for extra momentum of the shafts, from other places.

regards Ian

most probably don't tear into there bottom end much, if you get the bottom end professionally balanced and blueprinted you could remove the balance shaft all together potentially and have less vibration. Also possible higher rev limiter from everything working in sync