AD Boivin 2002 Snow Hawk, Service Manual

Page: 78 / 173

PRIMARY TRANSMISSION SYSTEM 8-10
ADJUSTMENT
Spring Preload
General information
During the break-in period for the new spring, it is normal for it to
settle slightly. The initial torsion of the spring is slightly higher to
compensate for this setting. These characteristics apply after
the break-in period (around 10 hours of use).
Initial spring preload
To verify the initial spring preload, use a spring scale hook (P/N
529 0065 00) and a spring scale.
Remove the drive belt.
Install the hook on the sliding sheave. While preventing the
fixed sheave from turning, use a spring scale to pull on the
sliding sheave perpendicularly to the rotational axis of the pulley.
Take a first measurement when the sliding sheave begins to
turn. Let it turn 10 mm (3/8 in) Hold the spring scale in this
position. Gently slacken the tension on the spring scale and
take the second measurement when the sliding sheave begins
to close. The initial spring preload will be the average of these
two measurements.
TYPICAL
Step 1 : 1st measurement
Step 2 : 2nd measurement
To correct the initial spring preload, change the position at which
the end of the spring is inserted into the helix; turning it
clockwise increases the torsion and counter-clockwise
decreases it.
The original spring preload on the Snow Hawk is 6.8 kg or 14.9
lbf
l
NOTICE:
It is not possible to correct the initial torsion of the spring, try
adjusting the position of the other end of the spring in the back
of the sliding sheave (holes A, B and C).
1
st
measurement
(when open)
2
nd
measurement
(when closed)
Initial
spring
preload
Example:
(when
open)
(when
closed)
Real
Initial
spring
preload