2001 YAMAHA YZ250F weight

4 - 63
ENGBALANCER
REMOVAL POINTS
Balancer shaft drive gear and balancer
shaft driven gear
1. Straighten the lock washer tab.
2. Loosen:
lNut (primary drive gear) 1
lNut (balancer shaft driven gear) 2
NOTE:
Place an aluminum plate a between the teeth
of the balancer shaft drive gear 3 and driven
gear 4.
Balancer shaft
1. Remove:
lBalancer shaft 1
NOTE:
When removing the balancer shaft, align the
center a of the balancer shaft weight along
the line connecting the centers of the crank-
shaft and balancer shaft.
INSPECTION
Primary drive gear, balancer shaft drive
gear and balancer shaft driven gear
1. Inspect:
lPrimary drive gear 1
lBalancer shaft drive gear 2
lBalancer shaft driven gear 3
Wear/damage ® Replace.
Balancer shaft
1. Inspect:
lBalancer shaft
Cracks/damage ® Replace.

4 - 64
ENGBALANCER
ASSEMBLY AND INSTALLATION
Balancer shaft, balancer shaft drive gear
and balancer shaft driven gear
1. Install:
lBalancer shaft 1
NOTE:
lApply the engine oil on the bearing.
lWhen installing the balancer shaft, align the
center a of the balancer shaft weight along
the line connecting the centers of the crank-
shaft and balancer shaft.
2. Install:
lBalancer shaft driven gear 1
NOTE:
Install the balancer shaft driven gear onto the
balancer shaft while aligning the punch mark
a on the balancer shaft driven gear with the
lower spline b on the balancer shaft end.
3. Install:
lBalancer shaft drive gear 1
NOTE:
lAlign the punched mark a on the balancer
shaft drive gear with the punched mark b on
the balancer shaft driven gear 2.
lAlign the punched mark c on the balancer
shaft drive gear with the lower spline d on
the crankshaft end.
4. Install:
lLock washer 1
lNut (balancer shaft driven gear) 2
lPrimary drive gear 3
lNut (primary drive gear) 4
NOTE:
lInstall the primary drive gear with its stepped
side a facing the engine.
lPlace an aluminum plate b between the
teeth of the balancer shaft drive gear 5 and
driven gear 6.
5. Bend the lock washer tab.
T R..50 Nm (5.0 m · kg, 3.6 ft · lb)
T R..75 Nm (7.5 m · kg, 54 ft · lb)

7 - 15
TUN
2. Use of stiff spring
Generally a stiff spring gives a stiff riding
feeling. Rebound damping tends to
become weaker, resulting in lack of a
sense of contact with the road surface or
in a vibrating handlebar.
To set a stiff spring:
lChange the rebound damping.
Turn in one or two clicks.
lChange the compression damping.
Turn out one or two clicks.
Coverage of spring by weight
õRider weight
1Soft
2Standard
3Stiff
SETTING

7 - 19
TUN
CAUTION:
When using a rear shock absorber other
than currently installed, use the one whose
overall length a does not exceed the stan-
dard as it may result in faulty performance.
Never use one whose overall length is
greater than standard.
Coverage of spring by weight
õRider weight
1Soft
2Standard
3Stiff
Length a of standard shock:
485.5 mm (19.11 in)
SETTING