Measuring The Axial Clearance Of The Crankshaft; Cylinder - Nikasil Coating; Measuring The Piston And Cylinder, Establishing The Mounting Clearance Of The Piston - KTM 690 LC4 2007 Repair Manual

5-5
1
x
y
2

Measuring the axial clearance of the crankshaft

– Insert the crankshaft and both transmission shafts in the right case
half. Mount the left case half.
– Mount and tighten the case screws.
– Mount the dial gauge support on the engine case and measure the
axial clearance of the crankshaft.
Axial clearance of the crankshaft: 0.15 - 0.25 mm
– If the measured value does not correspond to the set-point value,
correct the axial clearance.
– Remove the crankshaft and pull the inner ring off the crankshaft on
the ignition side using special tool 584.29.037.043. Now either
add or remove compensating washers.
NOTE: If the axial clearance is too large, add compensating washers; if
it is too small, remove some of the washers. Compensating washers
may only be added on the ignition side.

Cylinder - Nikasil coating

Nikasil is a trademarked cylinder coating process developed by the
Mahle piston manufacturer. The name is derived from the two materials
used in the process - a nickel layer in which the exceptionally hard
silicon carbide is embedded. The main advantages of the Nikasil
coating are its outstanding heat dissipation, the improved power
output, low wear and the low weight of the cylinder.
Measuring the piston and cylinder, establishing the mounting
clearance of the piston
– To establish the wear to the cylinder, use a micrometer to measure
the cylinder in the middle of the bearing surface.
– Measure the diameter of the cylinder in the X and the Y axis to
detect any ovality.
Cylinder diameter
NOTE: the cylinder size
1
piston size on the piston head.
2
– The piston is measured at the piston skirt across the piston pin, as
illustrated.
Piston diameter
– The piston mounting clearance is the difference between the
smallest cylinder diameter and the piston diameter.
Piston mounting clearance min. 0.03 mm - max. 0.10 mm
size I: 102.000 - 102.012 mm
size II: 102.013 - 102.025 mm
wear limit: max. 102.04 mm
is marked on the side of the cylinder, the
size I: 101.955 - 101.965 mm
size II: 101.966 - 101.975 mm