Yamaha RS90K, Service Manual

Page: 737 / 841

9-6
SPEC
MAINTENANCE SPECIFICATIONS
Valve spring:
Free length
Intake 39.73 mm (1.56 in)
<Limit> 37.7 mm (1.48 in)
Exhaust 39.73 mm (1.56 in)
<Limit> 37.7 mm (1.48 in)
Installed length (valve closed)
Intake 33.0 mm (1.30 in)
Exhaust 33.0 mm (1.30 in)
Compressed spring force (installed)
Intake 136 ~ 158 N (13.9 ~ 16.1 kg, 30.6 ~ 35.5 lb)
Exhaust 136 ~ 158 N (13.9 ~ 16.1 kg, 30.6 ~ 35.5 lb)
Spring tilt
Intake 2.5°/1.7 mm (0.07 in)
Exhaust 2.5°/1.7 mm (0.07 in)
Winding direction (top view)
Intake Clockwise
Exhaust Clockwise
Valve lifter:
Valve lifter outside diameter
Intake 24.482 ~ 24.488 mm (0.9639 ~ 0.9641 in)
<Limit> 24.457 mm (0.9629 in)
Exhaust 24.482 ~ 24.488 mm (0.9639 ~ 0.9641 in)
<Limit> 24.457 mm (0.9629 in)
Valve lifter hole inside diameter
Intake 23.15 ~ 23.30 mm (0.9114 ~ 0.9173 in)
<Limit> 23.33 mm (0.9185 in)
Exhaust 23.15 ~ 23.30 mm (0.9114 ~ 0.9173 in)
<Limit> 23.33 mm (0.9185 in)
Piston:
Piston size (D) 78.935 ~ 78.950 mm (3.1077 ~ 3.1083 in)
Measuring point (H) 5.0 mm (0.20 in)
Piston to-cylinder clearance 0.050 ~ 0.075 mm (0.0020 ~ 0.0030 in)
<Limit> 0.120 mm (0.0047 in)
Piston pin bore off set 0.5 mm (0.0197 in)
Off-set direction Exhaust side
Piston pin bore inside diameter 19.004 ~ 19.015 mm (0.7482 ~ 0.7486 in)
Piston pin:
Piston pin outside diameter 18.991 ~ 19.000 mm (0.7477 ~ 0.7480 in)
Piston pin length 52.9 ~ 53.0 mm (2.0827 ~ 2.0866 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)
Model RS90/RS90R/RSG90/RS90M/RST90/RST90TF
H
D