Mounting Instructions For Piston Rings; Piston Ring End Gap; Measuring Piston And Cylinder, Determining The Piston Fitting Clearance - KTM 400-660 LC4 1998-2005 Repair Manual

5-8E
Compression ring
Tapered ring
Oil scraper ring
x
y

Mounting instructions for piston rings

– Insert the oil scraper ring in the lower ring groove. Side of ring
marked facing piston head.
– Mount compression ring (tapered compression piston ring) in middle
ring groove. Side of ring marked facing piston head.
– Insert the compression ring (rectangular ring) in the upper piston ring
groove (the surface marked must be on top).
ELKO ELKO
Ø 89 mm Ø 95 mm
O O
TOP TOP
ELKO TOP

Piston ring end gap

– Insert pisto ring into the cylinder and adjust. Piston ring must be
approx. 10 mm (1/2 inch) from top of cylinder.
– The end gap
Compression rings: max. 0.80 mm (0.032 in)
If the end gap is greater check piston and cylinder for wear. If piston
and cylinder wear are within the permitted tolerance limits, replace the
piston ring.
Measuring piston and cylinder, determining the piston
fitting clearance
– In order to determine the wear of the cylinder, measure the cylinder
center of the running area with a micrometer.
– Measure the diameter of the x-axis and the y-axis in order to check
for oval wear, if any.
– The piston is measured on the piston skirt across to the piston pin as
shown in the illustration.
– The cylinder diameter minus the piston diameter yields the piston
assembly clearance.
Piston assembly clearence: see Technical Specification
ELKO ARIAS
Ø 101 mm Ø 101 mm
O N 100
TOP N 101
TOP
B
can now be checked which a feeler gauge.
Oil scraper ring: max. 1.00 mm (0.04 in)
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