Honda CRF450R Owner's Manual page 55

Adjustment
1. Loosen the rear axle nut.
2. Loosen the lock nuts and turn the adjusting bolt
counterclockwise to decrease slack or clockwise to
increase slack.
Align the index mark of the axle plates with the same
reference marks on both sides of the swingarm.
(1) REAR AXLE NUT (2) LOCK NUT
(3) ADJUSTING BOLT (4) AXLE PLATE
(5) REFERENCE MARKS (6) INDEX MARK
3. Tighten and torque the rear axle nut.
TORQUE: 94 Ibf ft (127 N m, 13.0 kgf m)
4. Recheck chain slack and adjust if necessary.
5. Loosen the adjusting bolt counterclockwise lightly
until it touches the axle plate. Then, tighten and
torque the lock nut by holding the adjusting bolt with
a wrench.
TORQUE: 20 Ibf ft (26 N m, 2.7 kgf m)
Removal, Cleaning and Inspection
For maximum service life, the drive chain should be
cleaned, lubricated, and adjusted before each outing.
1. Carefully remove the master link retaining clip with
pliers.
Remove the master link and drive chain.
2. Clean the drive chain in high flash-point solvent and
allow it to dry. Inspect the drive chain for possible
wear or damage. Replace any chain that has dam-
aged rollers, loose or tight fitting links, or otherwise
appears unserviceable.
(1) RETAINING CLIP (2) MASTER LINK
3. Inspect the sprocket teeth for possible wear or dam-
age.
Replace if necessary.
NOTE:
• Never install a new drive chain on badly worn
sprockets, or use new sprockets with a badly worn
drive chain. Both chain and sprockets must be in
good condition, or the new replacement chain or
sprocket(s) will wear rapidly.
• Excessively worn sprocket teeth have a hooked,
worn appearance. Replace any sprocket which is
damaged or excessively worn.
4. Measure a section of the drive chain to determine
whether the chain is worn beyond its service limit.
Put the transmission in gear, and then turn the rear
wheel forward until the lower section of the chain is
pulled taut. With the chain held taut and any kinked
joints straightened, measure the distance between
a span of 17 pins, from pin center to pin center. If
the measurement exceeds the service limit, replace
the chain. After the chain is measured, shift the trans-
mission into neutral again before proceeding with
inspection and service.
Replacement chain: D.I.D 520DMA2
SERVICE LIMIT: 10.20 in (259.0 mm)
MEASURE A SPAN OF 17 PINS (16 PITCHES)
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