Electric starter

I have a 2016 600cc, ProS, I would like to add a starter. I have a donor clutch kit, starter, battery box, ring gear, and wiring harness. The rear clutch sheave is different for electric start. I don’t want to buy a whole clutch assy. Question for the clutch guys can I swap or purchase the clutch sheave next to the motor? Would I need to have it rebalanced? I know the taper is different between engines.

do you mean the secondary clutch helix?

No, I'm talking about the primary clutch. The starter ring attaches to the primary. The sheave next to the motor is different for electric start.

You need a complete primary clutch with the starter ring gear. Polaris doesn't sell the sheave separate. They sell it as a complete clutch. I believe because they don't want people putting the ring gear on incorrectly and it coming off at 8500 rpm

You can buy the starter ring that fits your clutch, but you will need to rebalance. Not much of a savings over buying complete clutch with the starter ring installed.