KTM 50 SX JUNIOR - Manual (Page 21)

ENGLISH
20
MAINTENANCE WORK ON CHASSIS AND ENGINE
»
Cleaning the dust scrabbers of the telescopic fork
The dust-protection bellows [1] are to remove dust and coarse dirt particles
from the fork tube. However, after some time, dirt may also get in behind the
dust-protection bellows. If this dirt is not removed, the oil sealing rings located
behind it may start to leak.
For this purpose, use a screwdriver to lift the dust scrabbers out of the
slider tubes, clean them thoroughly with compressed air, spray the fork tubes
and dust scrabbers with Universal oil spray (Motorex Joker 440) or engine oil.
Then, push the dust-protection bellows into the outer tubes by hand.
No oil may reach the front tire or the brake disks since this would consider-
ably reduce the tire's road grip and the braking effect of the front brake.
Changing spring preloading of the shock absorber
This is easily done.
NOTE: Before changing the spring preload note down the basic setting, e.g.
how many threads are visible above the adjusting ring.
Remove the right side cover.
Loosen the locking ring [2] with the hook spanner. Change the spring preload
with the adjusting ring [3] and re-tighten the locking ring [2].
BASIC SETTING – SPRING PRELOAD:
50 SX Junior: . . . . . . . . . .5 mm (0.2 in)
50 SX: . . . . . . . . . . . . . . .3 mm (0.12 in)
Check chain tension
Put the motorcycle on the sidestand.
Chain tension has to be checked close to the lower rear shock mounting [A].
When pushing the chain upwards, the distance to the swingarm has to be
10 mm (0.4 in).
If necessary, correct chain tension.
– If chain tension is too great, parts within the secondary transmission (chain,
chain wheels, gear box and rear wheel bearings) will be subjected to unnec-
essary stress, resulting in premature wear and even chain breakage.
– Too much slack in the chain, on the other hand, can result in the chain
jumping off the chain wheels. If this happens, the chain could also block
the rear wheel or damage the engine. In either case the operator is likely
to lose control of the motorcycle.
– Be careful not to get your finger caught between the chain and the rear
sprocket or other components.
Correct chain tension
Release the hexagon nut of the wheel spindle [4] and turn the left and the
right hexagon nut [5] equally far.
Before tightening the hexagon nut of the wheel spindle to 40 Nm, ensure that
the supporting plates [6] are resting against the swing arm. Additionally,
check that the rear wheel is aligned with the front wheel.
Chain maintenance
For long chain life, good maintenance is very important. Chains without
O-rings should be cleaned in fireproof solvent regularly and afterwards
treated with hot grease or chain spray (Motorex Chainlube Racing).
Keep the rear wheel free of grease! Grease on the rear wheel will significantly
reduce the grip of the rear tire and the motorcycle could easily get out of
control.
When mounting the chain masterlink clip, the closed side of the masterlink
clip must point in running direction.
Also check sprockets and chain guides for wear, and replace if necessary.
1
2
3
5
6
4 6
5
10 mm
A