Mon, 19 Nov 2012, 06:16 AM
2013 NHRA Pro Stock Motorcycle Engine Specifications
Courtesy of NHRA Communications
"NHRA spent countless hours speaking with the engine builders and manufacturers as well as the
race teams to come up with the final engine specifications for 2013," said Glen Gray, vice
president of technical operations, NHRA. "As a result, we believe NHRA fans are in store for some
exciting side-by-side racing in the Pro Stock Motorcycle category in 2013."
• V-twin design - up to 160 cid
• In-Line 4 cylinder type - up to 107 cid
• V-twin engine cylinder angle is 60 degrees. Maximum allowable cylinder angle from vertical
is 45 degrees.
• Maximum bore spacing is 98mm for In-Line. Maximum cylinder offset on V-twin is 1".
• All V-twin engines must use a push-rod, rocker arm design for the valve activation. Minimum
push-rod length is 8.0".
• All in-line 4 cylinder engines must use the overhead camshaft design.
• Maximum 2 valves per cylinder for all engines.
• The only exception is the Kawasaki engine. The Kawasaki engine is allowed maximum of 4
valves per cylinder.
• Variable cam timing devices, pneumatic actuation and finger followers are not permitted.
• Fuel injection permitted.
• Direct injection (into the combustion chamber) not permitted.
• All ECU systems must be NHRA accepted.
• Maximum one injector per cylinder.
• All ignition systems must be NHRA accepted.
• Aftermarket crank triggered, capacitive discharge (cd) ignition systems permitted.
• Magnetos are not permitted.
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