What does this mean to us

[scotty]

[FONT=Arial, Helvetica, sans-serif]NHRA 2007 Pro Stock Motorcycle Rule Changes[/FONT]
[FONT=Verdana, Arial, Helvetica, sans-serif]Saturday, November 18, 2006 NHRA Technical Services[/FONT][FONT=Arial, Helvetica, sans-serif]Following is a summary of new rules for a 101 cid, 4 valve, 4 cylinder engine combination in Pro Stock Motorcycle. All engines must be 2000 model year or newer, and NHRA accepted. All existing 4 valve engine combinations (i.e., 1994 and newer at 87.2 cid and older 4 valve engines at 79 cid) in the NHRA Rulebook are deleted.
These changes are effective January 1, 2007.
ENGINE

• 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.
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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.
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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.
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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.
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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.
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WEIGHT

Minimum weight, bike plus rider, 615 lbs.
​

All other Pro Stock Motorcycle class rules and regulations apply.
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[focus frenzy]

I dont think it is much of a issue as the GS engine of choice in the fast bikes is based on the two valve GS engine.

 

[rosco15]

Seems to me like this would open them up to using the busa and the zx motors.

 

[Dink]

Am I reading this correctly??
All existing 4 valve engine combinations (i.e., 1994 and newer at 87.2 cid and older 4 valve engines at 79 cid) in the NHRA Rulebook are deleted.

Doesn't this mean either that you can no longer run a motor older than 2000 model year, OR that there are now no longer ANY restrictions on what you can do to it???

HUH??

Dink

 

[rosco15]

I take it to mean the older 4 valve motors are still restricted to a smaller piston. This is why nobody runs the 4 valve motors currently. But if you use a late model motor you can get out the big pistons. I see some harleys and buells going up for sale shortly.

 

[Dink]

I see some harleys and buells going up for sale shortly.

What Harleys and Buells?? the only part that is stock on "Harley" drag bike is the stickers!!

Dink

 

[RacingJake]

If you got good sponsorship it won't hurt a thing :mrgreen:

But for the low budget old school folks they will be heading over to IHRA 8O well maybe not since there is only a handfull of racers at that level or should I say that money level.

 

[Baatfam]

Seems to me like this would open them up to using the busa and the zx motors.

Exactly! Had breakfast with a guy Sunday who's building a prostock bike using a busa motor because of the rule change....
Looks like its gonna be interesting....

Bob T.

 

[Guest]

This new rule is for the busas and ZX14s.

GS motors have been virtually unlimited in Prostar for years and they are not as fast as the NHRA 2 valve motors.

If you have ecer seen a set of GS cases bores for the 1640 sleeve, you will see why they don't live very long.

Jay

 

[lecroy]

Scotty, were you hoping that a bunch of GS parts were going to show up on eBay as a result of this?