Yamaha BR250F Service Manual page 125

Installation
When installing the primary sheave, reverse
the removal procedure. Note the following
points:
1.
Before installing the primary sheave,
clean the oil off the tapered portion
of the crankshaft using a lacquer thinner.
2. Before tightening the primary sheave
mounting bolt, apply engine oil to the
thread portion of the mounting bolt and
its contact surface with the spring
washer.
Inspection
1. Visually inspect the V-belt for signs of
damage. Replace the belt, if it is
damaged.
2. Measure the width of the V-belt. If the
belt is worn beyond the wear limit,
replace it.
Belt width:
New: 31.6 mm (1.24 in)
Wear limit: 28.0 mm (1.10 in)
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Belt length:
1,099 mm (43.26 in)
3.
Measure the length of the V-belt. It
should be within specification; if not,
replace the belt.
3. Tighten the mounting bolts with the
special tools to specification.
Tightening torque:
A: 100 Nm (10 rn-kq, 72 ft-Ib)
B: 60 Nm (6.0 rn- kg, 43 ft·lb)
Tighten the bolt to A to properly seat
the primary sheave on the crankshaft.
Loosen the bolt, then torque it to B,
the final torque.
V-BELT
Removal
1. Turn the secondary sliding sheave clock-
wise, and push it towards the chain case.
2. While holding the sliding sheave in this
compressed position, remove the V-belt
from the secondary sheave. Then,
remove it from the primary sheave.
1. New 2. Wear limit
12 -
1.
V-belt length
Reassembly
When reassembly the V-belt, reverse the
removal procedure. Note the following points:
1. Before installing the V-belt, clean the
oil off the fixed sheaves and sliding
sheaves using a lacquer thinner.