Clutch/Drive Belt System; Drive Unit - Polaris 1999 Sportsman 400 Service Manual

CHAPTER EIGHT
CLUTCHIDRIVE BELT SYSTEM
II
Thi s chapter describes serv ice procedures for the
clutc h and dri ve belt sys tem. Ta bles 1-5 at the end
of the chapter list the drive system specifications.
The dr ive train includes the clut ch/drive belt sys-
tem, a transmission assembly and independent
sus-
pended rear shaft dri ve ax les . The clu tch/drive belt
sys tem is also called the Polaris Variable Transmi s-
sion or PVT. T he clutch/drive belt sys tem co nsists
of a drive pulley mountedon the left end o f the en-
gine crankshaft. a driven pulley mounted on the left
end of the tran smi ssion input sha ft and a belt con -
nectin g the two pulleys.
DRIVE UNIT
Torque is transferred from the engine crankshaft to
the transmission by the Polaris Variable Trausmis-
sia n (PVT). T he d rive unit automatica lly changes the
drive ratio to permit the machine to move from idle to
maximum speed. Major components including the
drive pulley assembly, dri ven pulley assembl y and
dri ve belt areshown in Figure
t .
T he drive and dr iven pulleys function as two vari-
able diameter pu lleys that automat ically vary the
amount of reduction . Changes in the reduction ratio
arc achieved by movin g the sides of the pulleys
closer togetheror
further apart,
Changing the gap bc-
tween the sides of the pulley causes the belt to move
up or down in the pulley groove, changing the elTec-
rive
diameter of the pulley. The se changes in pulley
diameter adjust to correspond with the prevailing
load and speed conditions as shown in Figure 2.
The shift sequence is determined by a combina-
tion of engine torque and engine speed. When the