Tuesday, September 26th, 2017

2007 NHRA Pro Stock Motorcycle Rule Revisions

Published on November 25, 2006 by   ·   No Comments

GENERAL RULE UPDATES

Scalloping, notching, etc. of brake rotors prohibited.

Flat shield must be incorporated into front wheel, minimum of 5 1/2 inches from the ground. (aka The Steve Johnson Rule)

ENGINE (For four-valve, four cylinder configurations)

*
* Maximum displacement 1,655 cc (101.0 cid) Maximum bore spacing 100.0 mm (3.937 inches)
* 4 valves per cylinder
* 1 spark plug per cylinder on all 4 valve applications
* Turbocharger, supercharger and/or nitrous oxide prohibited (same as all engines in PSM)

CASE

All cases must be NHRA accepted. Case must be an OEM production casting, or a casting or machined billet part based on the production design. Only those cases submitted by the OEM manufacturer will be considered for acceptance. Modification to any accepted case are prohibited except for repair purposes. Case must be identified with manufacturer’s [art/casting number.

CYLINDER BLOCK

If cylinder block is separate from engine case, then either the OEM production block or an NHRA accepted cylinder block is permitted. Block must be cast or machined billet. Only those cylinder blocks submitted by the OEM manufacturer will be considered for acceptance. If cylinder block is integral to engine case, modifications are only permitted in the bore area; i.e. to enlarge bore(s) or move bore spacing. All cylinder blocks must be identified with a manufacturer’s name.

CYLINDER HEAD

All heads must be NHRA accepted. Head may be an OEM production casting or a casting or machined billet part based on the production design. Only those heads submitted by the OEM manufacturer will be considered for acceptance. Chambers may be modified to accommodate bore spacing of block. Head must be identified with a manufacturer’s part/casting number.

CAMSHAFT(S) / VALVE TRAIN

OEM valve angles +/- 2 degrees mandatory. As with all engines in PSM, variable cam timing devices and/or gear drives are prohibited. Cam(s) must be driven by chain or belt only. Production, cam drive location mandatory. Only conventional coil spring type valve train permitted; pneumatic or other type valve trains prohibited.

CRANKSHAFT

One-piece, steel crankshaft with conventional journal bearings mandatory.

MATERIALS

Unless otherwise noted, all moving engine components are restricted to aluminum, steel, iron, titanium, or other conventional alloys. Magnesium, carbon fiber, Kevlar, ceramics, composites, beryllium or other exotic materials prohibited.

TRANSMISSION

Any transmission with a maximum of 6 forward speeds, minimum 4 forward speeds, permitted. Transmission case must be integral with cast or machined billet engine case.

WEIGHT

Minimum weight, bike plus rider, 615 lbs.

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