Valve Spring; Camshaft - Husqvarna SMR Owner's Manual

VALVE SPRING

The weakening of the springs causes a decrease of the engine
power and it aften is responsible of the noise and the vibra-
tions coming from the valves.
In this case, check the free length "L". When the working lim-
it indicated has been overcomed, replace the springs.
"L" new spring = 35 mm/ 1.38 in. (250); 43,4 mm/ 1.71 in.
(450-510)
Service limit: 33 mm/ 1.3 in. (250); 41 mm/ 1.6 in. (450-
510)
NOTE:
Replace all the spring valves when even one of these has over-
comed the the working limit.
Check the spring valve squareness. Error limit not above 1.5
mm (0.059 in.) on each side.

CAMSHAFT

Check that cam surfaces are scored, stepped, grooved etc.
Insert the camshaft between two references and then check de-
viation using two comparators.
Wear limit: 0.0039 in.
Check that the cams are in good conditions, without wear or
deformation.
Cam height "H"
INTAKE (new) = 36,57 mm/ 1.44 in.
EXHAUST (new) = 35,94 mm/ 1.41 in.
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