670 MXZ, SUMMIT, FORMULA SS & MACH I

The 670 engine is Rotax's best engine combination. It responds very well to modifications. Twin pipes net 8-10HP and 3-4 pounds of torque @ 8200-8300 RPM's over the single pipe. We also have a thicker base gasket which raises the port timing to match the port timing of the twin pipe 670 engines from Rotax. Head must be cut to bring compression back down. We have an Improve Stock or Prostock Race Packages that will produce 158HP @ 9000 RPM's. The race packages include race porting the cylinders and base, head machining & inserts, 2 cylinder race pipes. The Improve Stock Package will also include boring of the stock carbs. Neither of these 2 kits are for trail use. The labor to disassemble, clean, and assemble the motor is NOT included in the package price. Labor to disassemble and assemble carburetors in not included. Any crank work, repairs, or replacement parts would be an extra charge.