49
3-4-4 Cylinder and piston
-After removing the cylinder head and gasket,
take out the cylinder.
-Take off the cylinder gasket and clean the
crankcase surface.
-Place a clean cloth under the piston to prevent
any dust from falling inside the crankcase
chamber.
Remove the piston pin circlip and the piston.
-Inspect the cylinder inside surfaces show no
signs of seizure or anomalous wear, then
measure the inside diameter of the cylinder
with a bore meter.
Note:
*BH8 / BR8 / BF8*
125c.c. engine
Wear limit
Ф
52.5mm.
* BR9 / BF9*
151c.c. engine
Wear limit
Ф
57.5mm.
-Take measurements on three planes along the
cylinder axis; for each plane take a
measurement on the circumference.
-Take off the piston rings carefully.
Inspect the piston surface, anomalous wear is
not allowed.
Note: *BH8 /BR8/ BF8 / BK8* 125c.c. engine
Wear limit
∅
52.5mm.
*BR9/ BF9 / BK9* 151c.c. engine
Wear limit
∅
57.5mm.
