Suzuki DR-Z70 Service Manual page 65

3-33 ENGINE
PISTON TO CYLINDER CLEARANCE
• Subtract the piston diameter from the cylinder bore diameter.
• If the piston-to-cylinder clearance exceeds the service limit,
rebore the cylinder and use an oversize piston or replace both
the piston and cylinder.
Piston to cylinder clearance:
Service Limit: 0.120 mm (0.0047 in)
PISTON PIN AND PIN BORE
• Measure the piston pin bore diameter using the small bore
gauge.
• If the measurement is out of specification, replace the piston.
Piston pin bore I.D.:
Service Limit: 13.030 mm (0.5130 in)
09900-20602: Dial gauge (1/1000 mm)
09900-22401: Small bore gauge (10 – 18 mm)
• Measure the piston pin outside diameter at three positions
using the micrometer.
• If any of the measurements is out of specification, replace the
piston pin.
Piston pin O.D.:
Service Limit: 12.980 mm (0.5110 in)
09900-20205: Micrometer (0 – 25 mm)
PISTON RING TO GROOVE CLEARANCE
• Measure the side clearances of the 1st and 2nd piston rings
using the thickness gauge.
• If any of the clearances exceeds the limit, replace both the
piston and piston rings.
Piston ring to groove clearance:
Service Limit (1st) : 0.180 mm (0.0071 in)
(2nd): 0.150 mm (0.0059 in)
Piston ring groove width:
Standard (1st) : 1.01 – 1.03 mm (0.0398 – 0.0405 in)
(2nd): 1.21 – 1.23 mm (0.0476 – 0.0484 in)
(Oil) : 2.01 – 2.03 mm (0.0791 – 0.0799 in)
Piston ring thickness:
Standard (1st) : 0.97 – 0.99 mm (0.0382 – 0.0390 in)
(2nd): 1.16 – 1.18 mm (0.0457 – 0.0465 in)
09900-20205: Micrometer (0 – 25 mm)
09900-20803: Thickness gauge
NOTE:
Using a soft-metal scraper, decarbon the crown of the piston.
Clean the ring grooves similarly.