Xtz Models - Yamaha TDM850 User Manual

6»14 Frame, suspension and final drive
46 Check the spring for cracks and other
damage. Measure the spring free length and
compare the measurement to the specifications
at the beginning of the Chapter. If it is defective
or sagged below the service limit, renew the
springs in both forks. Never renew only one
spring. Also check the rebound spring on the
damper.
47 Examine the working surfaces of the two
bushes; if worn or scuffed they must be renewed.
To remove the bottom bush from the fork tube,
prise it apart at the slit using a flat-bladed
screwdriver and slide it off (see illustration
7.18). Make sure the new one seats properly.
48 Check the damper rod for damage and wear,
and renew it if necessary. Reassembly
49 If removed, slide the rebound spring onto the
damper rod. Insert the damper rod into the fork
tube and slide it into place so that it projects fully
from the bottom of the tube, then fit the seat onto
the bottom of the damper rod (see illustrations
7.38 and 7.20b).
50 Oil the fork tube and bottom bush with the
specified fork oil and insert the assembly into the
slider. Fit a new copper sealing washer to the
damper rod bolt and apply a few drops of a
suitable non-permanent thread
compound, then install the bolt into the bottom of
the slider (see illustration 7.21). Tighten the bolt
to the specified torque setting. If the damper rod
rotates inside the tube, use the tool described in
Step 37 to hold the damper rod.
51 Push the fork tube fully into the slider, then
oil the top bush and slide it down over the tube
(see illustration 7.22a). Press the bush squarely
into its recess in the slider as far as possible,
then install the oil seal washer (see illustration
7.22b). Either use the Yamaha service tool or a
suitable piece of tubing to tap the bush fully into
place; the tubing must be slightly larger in
diameter than the fork tube and slightly smaller in
diameter than the bush recess in the slider. Take
care not to scratch the fork tube during this
operation; it is best to make sure that the fork
tube is pushed fully into the slider so that any
accidental scratching is confined to the area
above the oil seal.
52 When the bush is seated fully and squarely
in its recess in the slider, (remove the washer to
check, wipe the recess clean, then reinstall the
washer), install the new oil seal. Smear the seal's
lips with lithium-based grease and slide it over
the tube so that its markings face upwards and
drive the seal into place as described above until
the retaining clip groove is visible above the seal
(see illustration 7.23).
Place the old oil seal on top
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of the new one to protect It
HilUT
when driving the seal into
place.
53 Once the seal is correctly seated, fit the
retaining ciip, making sure it is correctly located in
its groove (see illustration 7.24).
54 Lubricate the lips of the new dust seal then
slide it down the fork tube and press it into
position (see illustration 7.25).
55 Slowly pour in the specified quantity of the
specified grade of fork oil and pump the fork at
least ten times to distribute it evenly (see
illustration 7.26a); the oil level should also be
measured and adjustment made by adding or
subtracting oil. Fully compress the fork tube into
the slider and measure the fork oil level from the
top of the tube (see illustration 7.26b). Add or
subtract fork oil until it is at the level specified at
the beginning of the Chapter.
56 Clamp the slider upright in a soft-jawed vice
using the brake caliper mounting lugs, taking care
not to overtighten and damage them. Pull the fork
tube out of the slider as far as possible then install
the spring and the spring seat. On TRX models fit
the spacer and the washer.
57 Apply a smear of fork oil or grease to the
new top bolt O-ring. Install the top bolt assembly,
making sure the bottom of the damping adjuster
rod locates correctly into the hole in the top of the
damper rod, and thread the bolt into the top of the
fork tube (see illustration 7.29).
locking
Warning: It will be necessary to compress
A the spring by pressing it down
using the top bolt to engage the
threads of the top bolt with the fork
tube. This is a potentially dangerous
operation and should be performed with care,
using an assistant if necessary. Wipe off any
excess oil before starting to prevent the
possibility of slipping.
Keep the fork tube fully extended whilst pressing
on the spring. Screw the top bolt carefully into the
fork tube making sure it is not cross-threaded.
Note: The top bolt can be tightened to the
specified torque setting at this stage if the tube is
held between the padded jaws of a vice, but do
not risk distorting the tube by doing so. A better
method is to tighten the top bolt when the fork has
been installed in the bike and is securely held in
the bottom yoke.
58 Install the forks (see Section 6).

XTZ models

Disassembly
59 Always dismantle the fork legs separately to
avoid interchanging parts and thus causing an
accelerated rate of wear. Store all components in
separate, clearly marked containers
illustration).
60 Slacken the clamps securing the fork gaiter
and slide the gaiter off the top of the fork.
61 Before dismantling the fork, it is advised that
the damper rod bolt be slackened at this stage.
Compress the fork tube in the slider so that the
spring exerts maximum pressure on the damper
rod head, then have an assistant slacken the
damper rod bolt in the base of the fork slider (see
illustration 7.2). If an assistant is not available,
clamp the brake caliper mounting lugs in a soft-
jawed vice to support the fork.
62 If the fork top bolt was not slackened with the
fork in situ, carefully clamp the fork tube in a vice
equipped with soft jaws, taking care not to
overtighten or score its surface, and slacken the
top bolt.
63 Unscrew the fork top bolt from the top of the
fork tube.
A Warning: The fork spring is
pressing on the fork top bolt (via the
spacer) with considerable pressure.
Unscrew the bolt very carefully,
keeping a downward pressure on it and
release it slowly as it is likely to spring clear. It
is advisable to wear some form of eye and face
protection when carrying out this operation.
64 Slide the fork tube down into the slider and
withdraw the spacer, spring seat and the spring
from the tube. Note which way up the spring is
fitted.
65 Invert the fork leg over a suitable container
and pump the fork vigorously to expel as much
fork oil as possible.
66 Remove the previously slackened damper
rod bolt and its copper sealing washer from the
bottom of the slider. Discard the sealing washer
as a new one must be used on reassembly. If the
damper rod bolt was not slackened before
dismantling the fork, use the Yamaha service tool
(pt. nos. 90890-01326 and 90890-01327) to
prevent the damper rod from turning. This tool
is passed down
Use a ratchet-type tool when Installing the
fork top bolt. This makes it unnecessary to
remove the tool from the bolt whilst threading
it in making it easier to maintain a downward
pressure on the spring.
(see
Staned by Stalker