KTM 300 EXC, Repair Manual

Page: 155 / 289

18 ENGINE
153
18.4.12 Checking/measuring the piston
303083-10
(All 250 models)
–
Check the piston sliding surface for damage.
» If the piston sliding surface is damaged:
–
Replace the piston and, if necessary, the cylinder.
–
Check that the piston rings move easily in the piston ring grooves.
» If the piston ring is stiff:
–
Clean the piston ring groove.
Tip
An old piston ring can be used to clean the piston ring groove.
–
Check the piston rings for damage.
» If the piston ring is damaged:
–
Change the piston ring.
Info
Mount the piston ring with the marking facing upward.
–
Check the piston pins for discoloration or signs of wear.
» If the piston pin shows severe discoloration/signs of wear:
–
Change the piston pin.
–
Place the piston pin in the connecting rod and check the seating for play.
» If the piston pin seating has excessive play:
–
Change the connecting rod and piston pin.
303015-10
(All 300 models)
–
Check the piston sliding surface for damage.
» If the piston sliding surface is damaged:
–
Replace the piston and, if necessary, the cylinder.
–
Check that the piston rings move easily in the piston ring grooves.
» If the piston ring is stiff:
–
Clean the piston ring groove.
Tip
An old piston ring can be used to clean the piston ring groove.
–
Check the piston rings for damage.
» If the piston ring is damaged:
–
Change the piston ring.
Info
Mount the piston ring with the marking facing upward.
–
Check the piston pins for discoloration or signs of wear.
» If the piston pin shows severe discoloration/signs of wear:
–
Change the piston pin.
–
Place the piston pin in the connecting rod and check the seating for play.
» If the piston pin seating has excessive play:
–
Change the connecting rod and piston pin.
303013-10
–
Measure the piston at the piston skirt, at right angles to the piston pin, at a
distance
B
.