BOMBARDIER 1996 Ski-doo MX Z440 Handbook page 212

The solid steel roller pins can be drilled axially (lengthwise) with various size holes to vary the
weight from 16.5 grams down to 10.3 grams (about a 1/4 inch diameter hole), which is the weight
of the hollow steel pin. A 1/8 inch diameter hole drilled in the solid steel pin will give you about 14.5
grams. Also available are threaded steel and aluminum pins. These pins are used with set screws
to allow for very small weight changes.
The weight of the lever arms will have a similar effect on the shift RPM. Early TRA clutches used an
aluminum arm that weighed 37.9 grams. Starting in 1993, a heavier, reinforced aluminum arm was
used on larger engine types. This heavier arm is now standard in all TRA clutches. It weighs 39.1
grams. Most of the reinforcing is concentrated at the pivot end of the arm, so the additional weight
does not have a major effect on the shift curve, but changing from light aluminum arms to heavy
aluminum arms will require small adjustments to the pin weight to obtain the same shift curve. A
arm is also available (P / N 4860378 00) which weighs 27.3 grams.
The location of the center of gravity of the lever arm assembly will also affect the shift curve.
Magnesium arms with solid steel pins will "feel" different than aluminum arms with threaded
aluminum pins with 1 set screw. Both of these combinations have a total weight within 0.1 gram of
each other, but the center of gravity of the magnesium arm set up is much farther away from the
pivot pin than the aluminum arm set up. This magnesium arm set up will be "revier" at low ratios
and part throttle settings.
By adding or removing weight to or from the arms, we can fine tune the shift RPM to the engine
power peak.
If you increase the horsepower of the engine at the same RPM, you would normally add more
weight to keep the engine pulling as hard as possible and not over rev.
If you lighten the weights on the arms, you will be increasing the shifting RPM. However, your
vehicle will not "pull" as hard, since less centrifugal force is being generated.
This should be optimized by accurate testing under duplicatable conditions until the best weight is
found for your use.
On the newer TRA clutches, the 6 mm allen bolt that the roller arms pivot on is easily removable.
However, a steel, gold color tube is left in the clutch holding the arm in place. This tube can be very
difficult to remove. A simple solution to this is to remove the 6 mm Allen bolt and coat it with red,
Loctite 271 and reinstall the bolt, let it cure, and when fully cured, you can remove the Allen bolt
along with the sleeve since the two are now "locked" together.
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