The part is listed as NLA at Partzilla. ...PISTON-COMP-BRAKE Not Available 43020-1035
The cross-reference there indicates that a number of motorcycles use the same piston assy.
I did see a K&L 1000J Rr kit 32-8053 at Z1Enterprises.com.
Before popping the money for a kit be sure to peek inside the master for signs of corrosion pitting in the aluminum bore. You can't rebuild a deteriorated body.
