KTM 450 EXC USA Motorcycle User Manual


 
MAINTENANCE WORK ON CHASSIS AND ENGINE 53
» If the chain tension does not meet specifications:
Adjusting chain tension - after checking. ( p. 55)
Remove the motorcycle from the work stand. ( p. 38)
9.44Checking chain tension when fitting rear wheel
Warning
Danger of accidentsDanger caused by incorrect chain tension.
If the chain tension is too high, the components of the secondary power train (chain, engine sprocket, rear sprocket, bear-
ings in transmission and rear wheel) are under additional load. Apart from premature wear, in extreme cases the chain can
rupture or the countershaft of the transmission can break. On the other hand, if the chain is loose, it can fall off the engine
sprocket or the rear sprocket and block the rear wheel or damage the engine. Check the chain tension and correct if neces-
sary.
400213-10
Make sure that the chain adjusters are fitted correctly on the adjusting screws.
Push the chain up at the rear edge of the chain guide to measure the chain ten-
sion .
Info
The upper chain section must be taut.
Chain wear is not always even, so you should repeat this measurement at
different chain positions.
Chain tension 8… 10 mm (0.31… 0.39 in)
» If the chain tension does not meet specifications:
Adjust the chain tension when fitting rear wheel. ( p. 55)
9.45Checking the rear sprocket/engine sprocket for wear
400227-01
Check rear sprocket/engine sprocket for wear.
» If the rear sprocket / engine sprocket are worn:
Replace the rear sprocket/engine sprocket.
Info
When fitting the split link, always make sure that the closed side of
the locking clip faces forward (riding direction).
The engine sprocket, rear sprocket and chain should always be
replaced together.
Check the chain guide for tightness and wear.
9.46Checking chain wear
Jack up the motorcycle. ( p. 38)
00
0
BB
0
0
AA
1 2 3 16 17 18
400226-10
Shift transmission to neutral.
Pull on the upper part of the chain with the specified weight .
Guideline
Weight of chain wear measurement 10… 15 kg (22… 33 lb.)
Measure the distance of 18 chain links in the lower chain section.
Info
Chain wear is not always even, so you should repeat this measurement at
different chain positions.
Maximum distance at the longest
chain section
272 mm (10.71 in)
» If the distance is greater than the specified measurement:
Replace the chain.
Info
When you replace the chain, you should also replace rear sprocket
and engine sprocket.
New chains wear out faster on old, worn sprockets.