Cylinder/Piston - Husqvarna K 750 Workshop Manual

New, run-in engine approximately 10 bar
Rectify below 8 bar

CYLINDER/PISTON

Compression test
The test indicates leakage from
the combustion chamber.
Close the decompression
valve or fit the sealing plug
503 55 22-01.
503 55 22-01
Compression tester
Connect the compression tester
in the spark plug hole.
531 03 16-86
Compression test
– Run the engine warm.
– Connect the instrument.
– Make 5–6 attempts to start and
read the pressure. Evacuate the
pressure and repeat the procedure
a few times. Note the average
value for the tests.
Values less than 8 bar (120 psi)
indicate faults with on the cylin-
der, piston or piston rings.
Cylinder
Dismantling
It may be appropriate to secure
the engine body in a vice to
facili tate work. Use soft jaw
guards!
Dismantle the cylinder.
Compression test
The compression test indicates leakage
from the combustion chamber. If the
machine lacks engine power and is dif-
ficult to start this may be due to poor
compression.
Close the decompression valve or fit
the sealing plug 503 55 22-01 to eliminate
the decompression valve as the source of
the fault.
Compression tester
The compression test is performed using
the measurement instrument 531 03 16-86,
which is connected to the spark plug
hole. The valve below the gauge evacuates
the pressure.
Compression test
– Run the engine warm for a few minutes.
– Unscrew the spark plug and con nect
the instrument.
– Make 5–6 attempts to start and read
the pressure on the gauge. Evacuate the
pressure and repeat the procedure a few
times. Note the average value for the
tests.
The average value for a new and run-in
engine is approximately 10 bar (150 psi).
Values less than 8 bar (120 psi) indicate
faults with on the cylinder, piston or
piston rings.
Cylinder
Dismantling
It may be appropriate to secure the engine
body in a vice to facilitate work. Use soft
jaw guards!
Dismantle the 4 screws at the base of the
cylinder and lift off the cylinder.
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