There’s big horsepower gains to be made from proper cylinder porting and the BC/TPR CNC ported cylinder head for the Polaris XP1000 and XP Turbo applications deliver the best flow characteristics in terms of strength, direction, and condition of the air/fuel charge as it enters the cylinder through the intake valve. If you have exceptional charge motion, the cylinder will continue to fill even after the piston hits bottom dead center (BDC) and the air/fuel charge will evenly disperse in the chamber. All of this working cohesively makes horsepower.
Below is an explanation of the cylinder head pulldown menu process to the right. All BC CNC heads are bare with valve guides installed, you choose the port design (big or small) and the BC cam and valve train options (if any) that you want included with the cylinder head.
1. CYLINDER HEAD - Choose from big port design with +1mm intake and +3.8mm exhaust valves, intended for over 300whp. This option includes installing larger diameter valve seats on the exhaust side to accommodate the massive +3.8mm exhaust valves. The small port design features +1mm intake and +1mm exhaust valves and is intended for a milder build and better throttle response on a less modded engine.
2. CYLINDER HEAD CORE EXCHANGE - If you have a new or used cylinder head, you can select "yes" and use that as a core exchange for a $350 credit towards your BC CNC ported head. Select "no" if no cylinder head core exchange is required.
3. VALVE SPRING/RETAINER KIT - Chose from the BC0900, beehive spring with titanium retainers for race applications (low miles), the BC0900S, beehive spring with steel retainers for high mileage dune or trail applications or the dual spring with steel retainers for full drag race, high rpm use where valve control is at a premium. Or you can choose "none" if wanting to run stock or another manufacturer's spring/retainer kit.
4. CAM BUCKETS - Choose from standard, non-coated cam buckets or DLC coated buckets for high endurance or full race, high rpm applications. Choose "none" if wanting to run the stock Polaris cam buckets.
5. Choose from the BC premium billet keepers/locks or opt for "none" if choosing to use the stock stamped keepers.
6. Opt in for the premium BC valve stem seals, required if running BC valve spring/retainer kit. Or choose "none" if running stock valve train.
7. A valve shim adjuster kit is required if running the BC shim in retainer design. If running the Polaris OE cam buckets with shim adjustment in the bucket, this kit is not required.
8. If you want BC high performance cams included with your CNC ported cylinder head, please select from the options available...either XP Turbo or XP1000/RS1. Stage 2 cams recommended for mild dune and trail riding, Stage 3 for more aggressive/wild duner spec with added engine and tuning mods. The Stage 4 is strictly for professional builders who can provide proper tuning and required engine mods. Note: If opting for the small port design head, it is not recommended to over cam yourself and go with anything bigger than the Stage 3 spec.
9. The ARP cam cap bolt kit is the cherry on top of your high performance BC cylinder head package, utilizing stainless steel bolts for added strength and clamping capability.