Yamaha RST90GTZ, Service Manual

Page: 439 / 504

SPEC
9-6
Item Description
Valve spring:
Free length
Intake 40.14 mm (1.58 in)
<Limit> 38.14 mm (1.50 in)
Exhaust 40.14 mm (1.58 in)
<Limit> 38.14 mm (1.50 in)
Installed length (valve closed)
Intake 34.60 mm (1.36 in)
Exhaust 34.60 mm (1.36 in)
Compressed spring force (installed)
Intake 103.40 ~ 119.00 N (10.54 ~ 12.13 kgf, 23.24 ~ 26.75 lbf)
Exhaust 103.40 ~ 119.00 N (10.54 ~ 12.13 kgf, 23.24 ~ 26.75 lbf)
Spring tilt
Intake 2.5°/1.8 mm (2.5°/0.07 in)
Exhaust 2.5°/1.8 mm (2.5°/0.07 in)
Winding direction (top view)
Intake Clockwise
Exhaust Clockwise
Valve lifter:
Valve lifter outside diameter
Intake 26.482 ~ 26.488 mm (1.0426 ~ 1.0428 in)
<Limit> 26.457 mm (1.0416 in)
Exhaust 26.482 ~ 26.488 mm (1.0426 ~ 1.0428 in)
<Limit> 26.457 mm (1.0416 in)
Valve lifter hole inside diameter
Intake 26.500 ~ 26.518 mm (1.0433 ~ 1.0440 in)
<Limit> 26.548 mm (1.0452 in)
Exhaust 26.500 ~ 26.518 mm (1.0433 ~ 1.0440 in)
<Limit> 26.548 mm (1.0452 in)
Piston:
Piston size (D) 81.950 ~ 81.965 mm (3.2264 ~ 3.2270 in)
Measuring point (H) 11.0 mm (0.43 in)
Piston to-cylinder
clearance 0.035 ~ 0.060 mm (0.0014 ~ 0.0024 in)
<Limit> 0.120 mm (0.0047 in)
Piston pin bore offset 0.5 mm (0.02 in)
Offset direction Exhaust side
Piston pin bore inside diameter 19.004 ~ 19.015 mm (0.7482 ~ 0.7486 in)
<Limit> 19.045 mm (0.7498 in)
Piston pin:
Piston pin outside diameter 18.991 ~ 19.000 mm (0.7477 ~ 0.7480 in)
<Limit> 18.971 mm (0.7469 in)
Piston pin length 52.7 ~ 53.0 mm (2.07 ~ 2.09 in)
Piston pin to piston pin bore clearance 0.004 ~ 0.024 mm (0.0002 ~ 0.0009 in)
<Limit>
0.074 mm (0.0029 in)
MAINTENANCE SPECIFICATIONS