Big Bore Complete Kit (900cc) / Patriot 850 CHOOSE SLED FOR CLUTCH KIT:TRAIL Choose the compression ratio that

Choose the compression ratio that best matches your setup during checkout:

We start off by changing out the intake and exhaust valves with larger ones then CNC porting your head to our proven specs

No need for twin pipes any more

Diverts cab resonance

Increased horsepower through our advanced timing and fuel curve

Big Bore Complete Kit (900cc) / Patriot 850 CHOOSE SLED FOR CLUTCH KIT:TRAIL Choose the compression ratio thatThe Polaris 850 with its huge 74mm stroke was just asking for a bigger bore and we have done our homework to bring you the 900cc Big Bore. The all new piston was designed from scratch to accommodate all of the needs of the 900. The all new 88mm piston is an ultra high quality dual ring forged piston. Bikeman exclusive head profile giving you the most focused energy possible to make the most efficient power and maintain knock protection. If you are a