Back

www.ahrma.org

11.2 TECH INSPECTION & MODIFICATIONS

a) SUSPENSION: All machines must have no more than 7 inches of front wheel travel and 4 inches of rear wheel travel, measured at the
axle, regardless of original
specification.
The field check for rear wheel travel is as follows: 1) Both shocks are removed from the bike, then one bare (without spring) damper unit is reinstalled. 2)
The machine is supported in such a fashion that the rear suspension is at maximum
extension, and a measurement is taken from the center of the rear axle
to a point marked directly above the axle on the rear fender or sub frame. 3) With both wheels on
the ground, the rear suspension is fully compressed by the
examiner with the rider aboard to compress any rubber bumpers; a measurement is again taken from the center
of the rear axle to the same marked point above.
4) The measurement obtained in step 3 subtracted from the measurement in step 2 is the wheel travel.
An alternative method of determining wheel travel may be used by tech inspectors
using a pre-programmed computer. The program converts three dimensions
distance from swingarm pivot to rear axle, to lower shock mount and top shock
mountóto show the amount of travel of the shock shaft plus 50 percent of
the rubber
bumper.
Due to the use of non-standard or different types rubber bumpers, this
check may be overridden by the tech inspectorís discretion. Manual measurement of
shock movement is the overriding factor in determining whether a shock is legal.

To help preserve the motorcycles and represent the era, stock shock mount positions are strongly encouraged. Forward-mounted or laydown shock mounts
will be
closely scrutinized and checked for travel, with three-fourths of the rubber bumper counted as shaft travel.
1) Some manufacturers listed a limited number of machines for sale with specifications that exceed the suspension limits.
Those machines are not eligible unless
the amount of actual wheel travel is restricted to conform with the 7-inch/4-inch rule.
Regardless of the year and model of machine, it is the riderís responsibility
to actually measure and ensure that his or her machine is legal.
Do not rely on
printed specifications.

There will be no exceptions to the suspension limits.
Some of the machines sold with more than 4 inches of rear wheel travel are Honda, Yamaha, Kawasaki, Maico GP, 1974 Husqvarna, 1974 Bultaco,
1974
Montesa, 1974 CCM and 1974 KTM.
2) Any shock absorber may be used, providing the technology and design was
commercially available in 1974 or was supplied as OEM on any AHRMA-legal
machine.
Some legal shocks include 1974-era:

Armstrong Marzocchi

Bilstein Mulholland

Betor S&W

Curnutt Progressive Suspension

Fox Shocks Works Performance

Girling

Illegal shocks include:
Any shock with a separate remote reservoir (i.e., connected by a hose)
Any post-1974 technology, such as Fox air shocks, etc.

Single-shock machines are prohibited.
3) Pre-1975 OEM or aftermarket forks must be used; travel is limited to 7 inches.
Legal leading-axle 35mm forks include: AJS Stormer; Bultaco Sherpa S, Sherpa
T and Matador; Montesa; Kawasaki enduro; early Betor aftermarket; and external- spring Maico (36mm). Regardless of year manufactured, leading-axle
35mm forks which are not allowed include alloy- and magnesium-slider Marzocchi and
magnesium-slider Ceriani.

 

Back