Drive Chain - Honda CRF250X Owner's Manual & Competition Handbook

250X_084-103.qxd 08.7.3 10:13 ページ94

Drive Chain

Refer to Safety Precautions on page 25.
An endless (riveted master link) chain connects
the drive and driven sprockets. The O-ring chain
uses rubber between the side plates of the pin and
roller links to seal in the manufacturer-installed
lubricating grease and keep out moisture and dirt.
The service life of the chain depends on proper
lubrication and adjustment. Poor maintenance
can cause premature wear or damage to the drive
chain or sprockets.
Under severe usage, or when the motorcycle is
ridden in unusually dusty or muddy areas, more
frequent maintenance will be necessary.
Before servicing your drive chain, turn the
engine OFF, raise the rear wheel off the ground
by placing an optional workstand or equivalent
support under the engine and check that your
transmission is in neutral.
It is not necessary to remove or replace the drive
chain to perform the recommended service in the
Regular off-road Use Maintenance Schedule
(page 27).
94
Servicing Your Honda
Drive Chain Inspection
1. Stop the engine and raise the rear wheel off
the ground by placing the optional workstand
or equivalent support under the engine and
shift the transmission into neutral.
2. Check slack (1) in the upper drive chain run
midway between the sprockets (2) (3). Drive
chain slack should allow the following
vertical movement by hand:
25 – 35 mm (1.0 – 1.4 in)
NOTICE
Excessive chain slack may allow the drive chain
to damage the engine cases.
(1)
(2)
(3)
(1) drive chain slack (3) driven sprocket
(2) drive sprocket
If the chain is found to be slack in one segment
of its length and taut in another, this indicates
that some of the links are either worn, kinked or
binding. Kinking and binding can frequently be
eliminated by thorough cleaning and lubrication.
If the drive chain requires adjustment, procedure
is as follows:
Adjustment
1. Loosen the rear axle nut (1).
2. Loosen the lock nuts (2) and turn the
adjusting bolts (3) counterclockwise to
decrease slack or clockwise to increase slack.
Align the index mark (4) of the axle plates (5)
with same reference marks (6) on both sides
of the swingarm.
(4)
(5)
(2)
(3)
(6)
(1)
(1) rear axle nut (4) index mark
(2) lock nut (5) axle plate
(3) adjusting bolt (6) reference marks
3. Tighten the rear axle nut to the specified
torque:
127 N·m (13.0 kgf·m, 94 lbf·ft)
4. Recheck chain slack and adjust if necessary.
5. Turn the adjusting bolt counterclockwise
lightly until it touches the axle plate. Then,
tighten the lock nut to the specified torque by
holding the adjusting bolt with a wrench.
27 N·m (2.8 kgf·m, 20 lbf·ft)