Husqvarna 2011 SMS 125, Workshop Manual

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G.4
H06559
A
H06560
B
ENGINE OVERHAUL
Ed. 05-2011
Compression ratio check
To check if the compression ratio is correct, proceed as follows:
a) remove the cylinder together with the head from the crankcase ;
b) remove the piston from the connecting rod, carefully clean it and install it in -
side cylinder until it rests against the corresponding sector on the combustion
chamber (such part, as well, has to be cleaned from deposits)
c) screw a dial gauge into the spark plug hole, and reset it on the piston position
indicated in figure (A);
d) remove the piston and reassemble it on the connecting rod;
e) reassemble the cylinder together with the head inserting the 0.5 mm seal on
the crankcase;
f) take the piston to the T.D.C., and check that the reading on the dial gauge is
equal to 1.2 mm (0.05 in.) (figure B);
g) should the reading be different, restore the correct condition using a cylinder
foot gasket of suitable thickness.
Alternatively:
a) Remove the head, screw a dial gauge into the spark plug hole, and reset it
on a surface plane;
b) rest head onto cylinder, take piston to the T.D.C. and check that the reading
on the meter is 1.2 mm (0.05 in.);
c) should the reading be different, restore the correct condition by using a cyl -
inder foot gasket of thickness.
B - A= 1.2 mm / 0.047 in.