KTM 400-660 LC4 1998-2005, Repair Manual

Page: 65 / 501

Repair manual KTM LC4
Art.-Nr
. 3.206.024 -E
5-7F
Measuring and adjusting of crankshaft axial clearance
– Should the crankshaft, engine housing, or a roller bearing be
replaced, the axial clearance of the crankshaft should also be
checked.
– The housing should be laid inside upwards, then measure the
distance from the sealing area to the inner rings of the roller
bearings. Note the readings and then add on 0.3 mm to allow for
gasket thickness.
– Measure the crankshaft at touching points and then subtract the
measured value from the housing dimensions. This figure will be
the axial play of the crankshaft, which should be 0.03 - 0.12 mm
(up to model 2003). From model 2004: 0,10 - 0,20 mm (660
Rally 0,15 - 0,25 mm).
EXAMPLE:
Left-hand housing half 33.0 mm
Right-hand housing half + 32.8 mm
0.3 mm
Total housing dimension = 66.1 mm
Crankshaft dimension – 65.8 mm
Axial play present = 0.3 mm
The compensating washers should be equally distributed between the
two sides of the crankshaft. In our example, one compensation washer
(0.1 mm / 0.004 in.) must be mounted on either side.
Checking the piston
– Replace the piston in the case of excessive oil consumption or
grooves in the piston skirt.
– If reinstalling the old piston perform the following steps:
1. Piston bearing surface - check for damage
2. Piston ring grooves - the piston rings must move easily in the
groove. Old piston rings or sandpaper (400 grit) may be used to
clean the piston ring grooves.
3. Piston rings - check for damage and end gap (see below).
4. The piston pin must move freely in the piston when mounted. If the
piston pin changed its color badly or shows running traces, it must
be replaced. Insert piston pin also into the conrod and check for
clearance. Maximum clearance in the conrod eye 0.08 mm (0.003
in).
NOTE: When in place, the piston pin may not have any play. It must
be possible to shift it with slight counterpressure.