Cylinder And Piston - TGB BR8 Service Manual

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 Ф52.5mm.
* BR9 / BF9*
151c.c. engine
Wear limit Ф57.5mm.
-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.
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