Suzuki DR-Z70 Service Manual page 60

VALVE SPRING INSPECTION
The force of the coil spring keeps the valve seat tight. Weak-
ened spring results in reduced engine power output, and often
accounts for the chattering noise coming from the valve mecha-
nism.
• Inspect the valve spring for proper strength by measuring its
free length and also by the force required to compress it.
If the spring length is less than the service limit, or if the force
required to compress the spring does not fall within the range
specified, replace the spring.
Valve spring free length (IN. & EX.):
Service Limit: 34.5 mm (1.36 in)
09900-20102: Vernier calipers
Valve spring tension (IN. & EX.):
Standard: 157 – 181 N (16.0 – 18.5 kgf, 35.3 – 40.8 lbs)
CAM WEAR
Check the camshaft for damage or wear on the cam face. Mea-
sure the cam height H with a micrometer.
Replace the camshaft assembly if defects is found or cam height
H is less than the service limit.
Cam height H:
Service Limit (IN.) : 27.09 mm (1.067 in)
(EX.): 26.95 mm (1.061 in)
09900-20202: Micrometer (25 – 50 mm)
CAMSHAFT BEARING INSPECTION
Rotate the camshaft bearing outer race by finger to check for
abnormal play, noise and smooth rotation.
Replace the right bearing in the following procedure if there is
anything unusual.
RIGHT BEARING REPLACEMENT
• Remove the camshaft right bearing with the special tool.
09913-60910: Bearing & gear puller
If the left bearing is faulty replace the camshaft
assembly.
at length 25.5 mm (1.00 in)
157 – 181 N (16.0 – 18.5 kgf, 35.3 – 40.8 lbs)
25.5 mm (1.00 in)
ENGINE 3-28