11.2 TECH INSPECTION & MODIFICATIONS
a) SUSPENSION: All machines must have no more than 7 inches of front
travel and 4 inches of rear wheel travel, measured
axle, regardless of original
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
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
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
using a pre-programmed
computer. The program converts three dimensions
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
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
To help preserve the
motorcycles and represent the era, stock shock mount positions
are strongly encouraged.
Forward-mounted or laydown shock mounts
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
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
Regardless of the year and model of machine, it is the riderís
to actually measure and ensure
that his or her machine is legal.
Do not rely on
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,
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
Some legal shocks include 1974-era:
Curnutt Progressive Suspension
Fox Shocks Works Performance
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
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,
T and Matador; Montesa; Kawasaki enduro; early Betor aftermarket; and
spring Maico (36mm). Regardless of year manufactured, leading-axle
forks which are not allowed include alloy- and magnesium-slider Marzocchi