Product Description

Each cylinder head dome includes a dome locking system that prevents it from spinning when servicing spark plugs. Not all cylinders are the same and compression may vary.
NOTE: All Cylinder Head Domes Are Sold Individually.

• 82mm domes (701) intended for use with 81.00mm to 83.50mm piston size.
• 85mm domes (760) intended for use with 84.00mm to 85.50mm piston size.
• 89mm domes (850) intended for use with 89.00mm to 90.00mm piston size.

701cc Compression Chart

82mm Chamber 701 (61X) No Porting @ Sea Level
(NOTE: Stock 701 Cylinder is 81.00mm)

• 29cc = 230psi*
• 31cc = 210psi*
• 33cc = 195psi*
• 35cc = 185psi*
• 37cc = 170psi
• 39cc = 160psi

* = must use 100+ octane fuel

760cc Compression Chart

85mm Chamber 760 No Porting @ Sea Level
(NOTE: Stock 760 Cylinder is 84.00mm)

• 32cc = 225psi*
• 34cc = 215psi*
• 36cc = 195psi*
• 38cc = 185psi*
• 40cc = 170psi

NOTE: These are estimations only. Many factors could change actual compression (port timing, squish, deck height and piston selection).