lowest gear ratio, just like sprockets
do on a sport quad. When you hit the
gas pedal, the primary clutch shifts
out and grabs the belt to produce forward movement. As rpm climbs to
the setting produced by your clutch
calibration, the clutches move to the
shifting phase. As the primary clutch
squeezes inward and causes the belt
to ride up on the sheaves, the secondary clutch releases and causes
the belt to ride lower in the sheaves.
This inverse effect happens in harmo-
ny and keeps belt tension and length
constant so that no slippage occurs. If
the clutches are not calibrated in a
manner that they sync up, belt slip-
page will occur. As the belt rides up
or down on the sheaves, the diameter
of the clutch changes in relation to
where the belt contacts it. As the pri-
mary clutch moves in and the belt
rides higher, it produces a higher
gear ratio by increasing the amount
of revolutions the belt makes per
engine rpm. The secondary clutch
getting smaller amplifies the effect; a
smaller rear “sprocket” increases the
amount of revolutions the rear
wheels make per engine rpm.
Our EPI clutch kit came with a pri-
mary and secondary spring and a
new machined helix, but no weights.
For our machine setup, the stock
weights work well, and EPI offers
many kits to suit your modifications,
elevation, tire size and terrain. Check
out www.epiperformance.com for
more information. The machined
helix in the EPI kit looks much differ-
ent than the stock one; there is no bot-
tom profile to slow the upshift on the
secondary clutch. After installing the
EPI kit (read on for a full walk-
through), the shifting was improved
from off-idle to top speed, and the
RZR pulled more consistently and
harder through the shifting phases.
On/off throttle response quickened by
a noticeable amount, which is
referred to as “backshift” (the clutch’s
ability to maintain pressure and
engagement when the throttle is
chopped and reapplied, creating
quick acceleration whenever you
stab the pedal). Belt grip was notice-
ably increased; we didn’t slip the belt
or smell it burning even on the tough-
est hill climbs we could find. The
overall improvement is a tighter feel
to the clutch that helps the RZR XP
feel even sportier, with increased
acceleration and lightning-quick
throttle response. The kit tested here
retails for $329.95, but sport utility
clutch kits start at $189.95.
STEP 5: Using a long socket extension or screwdriver,
hold the primary clutch steady while you slowly thread
the puller into the clutch. Be careful, because when the
clutch pops off the shaft, it pops off pretty hard!
STEP 6: When the primary clutch is loose, remove it
from the shaft and place it on a clean rag.
STEP 7: Next, carefully remove the belt from the secondary clutch, ensuring you don’t damage it.
STEP 8: Pull the secondary clutch off of the shaft. It has
a splined inner ring, so no puller is needed.