KTM 250 EXC RACING Owner's Manual page 119

5-4E
Grooved ball bearing and seal ring of balancer shaft.
1 2
Use a bearing extractor to pull the grooved ball bearing out of the casing
half and remove the seal ring.
2
Press a new shaft seal ring in to a flush position, its open side facing
1
downward.
Press new grooved ball bearing in up to the stop.
1
Grooved ball bearing of shift roller
3
4 Remove the screw .
A
At a casing temperature of approx. 150°C, the grooved ball bearing will
fall out from the bearing seat almost by itself.
If necessary, knock the casing half lightly on a planar wooden board.
Press new grooved ball bearing in to a flush position. Coat the thread of
the screw with Loctite 243 and tighten the screw to 6 Nm.
A
Needle bearing of shift shaft
4
Press needle bearing from the outside to the inside.
Press new needle bearing in from the outside and up to a flush position.
A
3
– Once the casing half has cooled down, check if the fit of the
bearings is tight.
Kickstarter release plate
5
When exchanging the release plate, secure both bolts with
Loctite 243 and tighten to 10 Nm.
5
The oil pump casing must not have any score marks or seizing marks.
6
Check oil ducts for unobstructed passage.
7
6
NOTE: In order to clean all oil ducts and check them for unhindered
passage you should dismantle both jets and the bypass valve (see
below).
7
Oil jet "60"
8
Dismount the oil jet and blow compressed air through the oil duct.
8
Degrease the thread of the oil jet, apply Loctite 243 and mount the oil
jet.
NOTE: Through this jet, engine oil is sprayed to the piston bottom in
order to cool the piston.