There’s big horsepower gains to be made from proper head porting and BC offers CNC ported cylinder heads that are IN STOCK and ready to ship for immediate delivery for the Yamaha YXZ / 998 applications. These heads 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. Each head design has seen extensive R&D, thousands of miles of testing, both on the dyno and out in the field in order to determine the absolute best performing combination of parts that also delivers unprecedented reliability. If stock bottom end or stock stroke crank with stock or Stage 2 cams, we recommend the small valve setup (STD stainless steel intake / STD Inconel exhaust). If running a stroker kit or full race application, recommend the big valve setup (STD SS intake / +1mm Inconel exhaust) for added flow and performance. Then it's alacarte on the remaining valve train. Choose from the BC dual valve springs wound by PAC, featuring extra processing procedures for enhanced durability, steel retainers, keepers, BC camshafts (new cores...not regrinds!) and the ARP head studs are all available as add-ons.

Heads are available fully loaded and lashed with the optional BC parts for an added assembly fee of $200.

The BC core exchange program works three ways:

1. Buy one of BC's new heads outright, no exchange.
2. Send a new head in for even exchange for one of BC's new "in-stock" heads.
3. Send a used head in, receive that same head back.

BC only accepts new, never-been ran Yamaha YXZ (#2HC-11101-09-00) cylinder heads as new core exchanges. BC uses only new heads for all new even exchanges. All heads come with BC bronze valve guides installed as well as STD Stainless Steel intake & STD or +1mm Inconel exhaust valves. Any valve springs, retainers, keepers, cams or ARP head studs are sold separately in the pulldown menus.

If sending a new head, allow 1 week for inspection before new CNC head ships. If sending a used head, allow 4-8 weeks for that head to be ported. No exchanges on used heads. Send heads for servicing here:

BrianCrower, Inc, 161 So Marshall Ave, El Cajon CA 92020