I did talk to the CNC shop about remachining old bolt weights. Unfortunately, it cannot be done. They said something about a fixturing problem and it warping after it is machined to the new spec's.
As an alternative, you can purchase the 750 RPM bolt weight by itself for $110.00 and a new full length spring for $8.00 plus $8.90 for shipping. Total: $124.90. You would need to remove the old bolt weight from the bolt assembly and use blue loctite and torque and stake the bolts.
If you would like to send it to me for retrofitting the total cost including return shipping will be $139.90.
Richard Lage
Lage Manufacturing, L.L.C.
www.max-11.com