Polaris Trailboss 7174820 - Manual (Page 88)

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MAINTENANCE AND LUBRICATION
PVT System
The basic operation of the Polaris PVT system is dependent on engine
speed and vehicle torque requirements. As engine speed increases, the
force exerted on the movable drive sheave by the flyweights also
increases. This, in turn, increases the amount of “pinch” applied to the
drive belt. Similarly, if the engine speed decreases, the amount of
centrifugal force decreases, reducing the amount of belt “pinch.” This
begins to occur at speeds of less than 5 MPH, due to the system’s
dependence on engine speed.
For example, when operating at a ground speed of 3 MPH, the engine
would be running at only about 1500 RPM, with an engagement speed
of about 1400 RPM. Whenever operating this close to the engagement
point, the engine may be running at a speed too low to provide the
adequate “pinch” needed to prevent incomplete engagement.
Incomplete engagement creates excessive heat that can destroy belts
and clutch covers. In some cases, excessive clutch wear and damage
may result.
If the ATV will be operated for extended periods below 5 MPH, or for
towing loads, we recommend that you install a one tooth smaller
counter shaft sprocket on the transmission to raise the operating RPM
far enough above the engagement RPM to reduce heat caused by
incomplete engagement. Reducing the temperature inside the clutch
cover extends the life of the PVT components (belt, cover, etc.).
NOTE: Avoid heavy pulling and extended low speed
operation.