Pvt System; Overview; Drive Spring; Clutch Weight - Polaris 340 LX 2007 Service Manual

PVT System

PVT SYSTEM

Overview

CAUTION
Because of the critical nature and precision balance
incorporated into the PVT system, it is absolutely
essential that no attempt at clutch disassembly and/or
repair be made without factory authorized special tools
and service procedures. Polaris recommends that only
authorized service technicians that have attended a
Polaris-sponsored service training seminar and
understand the proper procedures perform adjustments
or repairs.
The Polaris drive system is a centrifugally actuated
variable speed belt drive unit. The drive clutch, driven
clutch, and belt make up the torque converter system.
Each clutch comes from the factory with the proper
internal components installed for its specific engine model.
Therefore, modifications or variations of components at
random are never recommended. Proper clutch setup and
adjustments of existing components must be the primary
objective in clutch operation diagnosis.

Drive Spring

The drive spring opposes the shift force generated by the
clutch weights, and determines the neutral RPM,
engagement RPM, and wether the engine RPM remains
flat, rises, or falls during shift out. When changing only the
drive spring, installing a spring with a lower pre-load rate
will result in a lower engagement RPM speed, while
installing a spring with a higher pre-load rate will result in
a higher engagement RPM.

Clutch Weight

The clutch weights generate centrifugal force as the drive
clutch rotates. The force generated changes in relation to
the engine RPM and with specified weight of each clutch
weight. When changing only the clutch weights, a lighter
weight will result in a higher engagement RPM, lower
shifting force, and higher shift out RPM. Installing heavier
weights has the opposite effect

Neutral Speed

Engine RPM when the force generated by the clutch
weights is less than the pre-load force generated by the
drive spring. In this mode, the drive clutch is disengaged.
7.2

Engagement RPM

Engine RPM when the force generated by the clutch
weights overcomes the drive spring pre-load force and the
moveable sheave begins to close or "pinch" the drive belt.
The engagement mode continues until no more belt
slippage occurs in the drive clutch. Once 100% belt
engagement is achieved, the sled will accelerate along the
low ratio line until the drive clutch up shift force overcomes
the opposing shift force generated by the driven clutch.

Shift Out Over-Rev

Engine RPM that spikes above the desired operating RPM
speed. The shift out RPM should come down to the
desired operating RPM, but never below, after the driven
clutch begins to open.

Shift Out RPM

Engine RPM at which the up shift force generated by the
drive clutch overcomes the shift force within the driven
clutch. In this mode, the drive clutch will move the belt
outwards, and the driven clutch will allow the drive belt to
be pulled down into the sheaves.
During WOT operation, the shift out RPM can be seen as
the maximum, sustained RPM displayed on the
tachometer. The shift out RPM should be the same RPM
as the recommended engine operating RPM. If the shift
out RPM is above the recommended engine operating
RPM, install heavier drive clutch weights. If the shift out
RPM is below the recommended engine operating RPM,
install lighter drive clutch weights.
The shift out RPM should remain constant during both the
upshift and back shift modes.

Driven Spring

A compression spring (Team driven / P2) or torsional
spring (Polaris P-85 driven clutch) works in conjunction
with the helix, and controls the shift rate of the driven
clutch. The spring must provide enough side pressure to
grip the belt and prevent slippage during initial
acceleration. A higher spring rate will provide more side
pressure and quicker back shifting but decreases drive
system efficiency. If too much spring tension exists, the
driven clutch will exert too much force on the belt and can
cause premature belt failure.
9923396 - 2007-2012 EDGE/Widetrak LX Service Manual
©2011 Polaris Sales Inc.