Duncan Racing's Complete 660cc Engine Performance Package for the Yamaha Raptor

Includes:
Fat Boy 4 Complete Exhaust System, 660cc Forged JE Piston Kit (12-1 or 10.75-1 compression) head gasket, Hard faced Camshaft, HD Valve Springs w/Titanium Retainers, Shortened Bronze Guides, DR Head Porting (with guides out) and Valve Seat Cut, Instructions, DR Tech Support. *Cylinder Head is returned assembled and ready to install.


Kit Options:
Camshaft Options
X3H Grind "All Around" Power Gain. Lift .452”/.429”, Duration 276°/274°
X14H Grind "Full Race/Top End" Power Gain. Lift .452”/.412”, Duration 292°/294°
DRI uses hardfaced camshafts only for the Raptor. A hardfaced camshaft is made from a stock OEM core. Lobes are welded up, camshaft profile is changed, camshaft is heat treated. On a hardfaced style cam.

*DRI only uses this design because it is the most reliable option for this model.

Compression: 10.75-1 or 12-1

Customer Cores Required:
Customer must send in to DRI their Cylinder (optional), Head, Camshaft for modification. (Or purchase new cores)
Kit Price is plus any OEM parts.
**For more Engine Kit options check the Buyers Guide section**