Norton Commando Black Diamond Oversized Exhaust Valve 1.36" Diameter

Race-proven durability!

Our MAP valves feature black oxide nitrating (a superior hardening process) which penetrates into the ultra-EV8 stainless steel core material, forming a super-hard outer layer. This "Black Diamond" finish adds surface hardness as well as a smoother exterior coating which greatly reduces friction. This reduction in friction allows for tighter tolerances (fit) and provides long-lasting durability.

• These valves are vastly superior to factory valves and other so-called "performance" finishes such as hard chrome.
• Our induction welded, heat-treated tip prevents mushrooming and eliminates the need for lash caps.

Oversized Valves

• Our oversized valves (OS) are flow tested for maximum performance.
• Oversized valves can also be used to rejuvenate sunken valve seats while correcting valve geometry.
• The OS valve features relocated keeper locations to accommodate hi-lift racing cams and springs. This saves additional machining expense.

NOTE: Always be sure to check piston clearance before installing oversize valves.

NOTE: Always be sure to check piston clearance before installing oversize valves.

FITS:

• 1969 and later Norton Commando models.