Motor Top End Controls; Inspection Of The Cylinder For Wear; Piston / Cylinder Clearance - SHERCO 250 SEF-R Workshop Manual

 Remove the cylinder head bolts (Be
sure to loosen them in the correct
direction).
ATTENTION : Black bolt N°1 on the
picture is longer, 3 bolts are identical.
 Remove the cylinder head.
 Remove the head gasket and the
cylinder.

MOTOR TOP END CONTROLS

Inspection of the cylinder for wear

Measure the inside diameter of the cylinder
when it is cold.
Inspect the inside of the cylinder for any
scratches or other evidence of abnormal wear.
If the cylindecar is badly damaged or worn it
should be replaced.
Since the cylinder does not wear in a uniform
manner measure in from side to side and up
and down as shown.
If the inside measurement of the cylinder
exceeds the tolerance limit it must be
replaced.
(A)=10 mm
(B)=25 mm

Piston / cylinder clearance

To determine the piston / cylinder clearance as
accurately as possible it is sufficient to
measure the piston and the cylinder, and then
calculate the difference between the two
values. Measure the diameters as shown.
Piston / cylinder clearances
Standard 0.03 – 0.05 mm
Limit 0.10 mm
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