Suzuki DF 2.5 Service Manual page 30

4. Measure the valve clearance by inserting thickness gauge
between the valve stem end and the rocker arm.
 09900-20803: Thickness gauge
Valve clearance (cold engine condition):
IN. & EX. 0.13 – 0.17 mm (0.005 – 0.007 in)
If the valve clearance is out of the specification, adjust the clear-
ance.
ADJUSTMENT
5. Loosen the lock nut 1 while holding the adjusting screw 2.
6. Turn the adjusting screw 2 to bring the valve clearance to
within the specification.
 09900-20803: Thickness gauge
7. Tighten the lock nut 1 to the specified torque while holding
the adjusting screw 2.
 Valve adjusting lock nut: 7 N·m (0.7 kg-m, 5.0 lb-ft)
8. Recheck the valve clearance.
PERIODIC MAINTENANCE 2-9
Valve clearance