2006 YAMAHA YZ450F weight

4 - 65
ENGBALANCER
ASSEMBLY AND INSTALLATION
Balancer, balancer drive gear and balancer
driven gear
1. Install:
Balancer driven gear 1
NOTE:
Install the balancer driven gear and balancer
shaft with their lower splines a aligning with
each other.
2. Install:
Balancer drive gear 1
NOTE:
Align the punched mark a on the balancer
drive gear with the punched mark b on the
balancer driven gear.
Install the balancer driven gear and crank-
shaft with the lower splines c aligning with
each other.
3. Install:
Lock washer 1
Nut (balancer driven gear) 2
Primary drive gear 3
Conical washer 4
Nut (primary drive gear) 5
Straight key 6
Balancer 7
Lock washer 8
Nut (balancer) 9
NOTE:
Apply engine oil to the contact surface and
threaded portion of the nut (primary drive
gear).
Place an aluminum plate a between the
teeth of the balancer drive gear 0 and bal-
ancer driven gear A.
Install the primary drive gear with its weight
reduction holes b facing the engine.
Install the conical washer with its convex sur-
face c outward.
4. Bend the lock washer tab.
a 0
1A
2
T R..50 Nm (5.0 m · kg, 36 ft · lb)
E
A
0a
c b
5
4
3
T R..110 Nm (11.0 m · kg, 80 ft · lb)
T R..45 Nm (4.5 m · kg, 33 ft · lb)

7 - 14
TUNSETTING
EC72A001
Setting of spring after replacement
As the front fork setting can be easily affected
by rear suspension, take care so that the
machine front and rear are balanced (in posi-
tion, etc.) when setting the front fork.
1. Use of soft spring
Generally a soft spring gives a soft riding
feeling. Rebound damping tends to
become stronger and the front fork may
sink deeply over a series of gaps.
To set a soft spring:
•Change the rebound damping.
Turn out one or two clicks.
•Change the compression damping.
Turn in one or two clicks.
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:
•Change the rebound damping.
Turn in one or two clicks.
•Change the compression damping.
Turn out one or two clicks.
ÈCoverage of spring by weight
ÉRider weight
1Soft
2Standard
3Stiff

7 - 17
TUNSETTING
EC72G001
Setting of spring after replacement
After replacement, be sure to adjust the spring
to the set length [sunken length 90 ~ 100 mm
(3.5 ~ 3.9 in)] and set it.
1. Use of soft spring
•Set the soft spring for less rebound
damping to compensate for its less spring
load. Run with the rebound damping
adjuster one or two clicks on the softer
side and readjust it to suit your prefer-
ence.
2. Use of stiff spring
•Set the soft spring for more rebound
damping to compensate for its greater
spring load. Run with the rebound damp-
ing adjuster one or two clicks on the
stiffer side and readjust it to suit your
preference.
*Adjusting the rebound damping will be fol-
lowed more or less by a change in the com-
pression damping. For correction, turn the
low compression damping adjuster on the
softer side.
CAUTION:
When using a rear cushion other than cur-
rently installed, use the one whose overall
length
a does not exceed the standard as
it may result in faulty performance. Never
use one whose overall length is greater
than standard.
ÈCoverage of spring by weight
ÉRider weight
1Soft
2Standard
3Stiff
Length
a of standard shock:
488.5 mm (19.23 in)