Yamaha UMAX Service Manual page 27

Valve, valve seat, valve guide
Valve clearance cold
Intake and exhaust side
Valve dimensions
Valve seat contact width (intake)
Valve seat contact width (intake) limit
Valve seat contact width (exhaust)
Valve seat contact width (exhaust) limit
Valve-stem-to-valve-guide clearance (intake)
limit
Valve-stem-to-valve-guide clearance
(exhaust) limit
Valve stem runout
Valve push rod
Valve push rod runout
Valve spring
Free length (intake)
Limit
Free length (exhaust)
Limit
Cylinder
Bore
Wear limit
Piston
Piston-to-cylinder clearance
Diameter
Piston pin outside diameter
Limit
Piston pin bore inside diameter
Limit
Piston-pin-to-piston-pin-bore clearance
Piston ring
Top ring
Ring type
End gap (installed) limit
Ring side clearance
2nd ring
Ring type
End gap (installed) limit
Ring side clearance
Crankshaft
Runout limit
Crankshaft pin outside diameter
Crankshaft pin to connecting rod clearance
ENGINE SPECIFICATIONS (YUM1A/YUM2A)
2-4
0.05–0.09 mm (0.0020–0.0035 in)
0.7–0.9 mm (0.0276–0.0354 in)
1.6 mm (0.063 in)
0.7–0.9 mm (0.0276–0.0354 in)
1.6 mm (0.063 in)
0.080 mm (0.0032 in)
0.100 mm (0.0039 in)
0.010 mm (0.0004 in)
0.15 mm (0.006 in)
36.2 mm (1.43 in)
34.4 mm (1.35 in)
36.2 mm (1.43 in)
34.4 mm (1.35 in)
85.000–85.020 mm (3.3465–3.3472 in)
85.050 mm (3.3484 in)
0.043–0.057 mm (0.00017–0.0022 in)
84.977–84.998 mm (3.3456–3.3464 in)
19.995–20.000 mm (0.7872–0.7874 in)
19.975 mm (0.7864 in)
20.0004–20.015 mm (0.7876–0.7880 in)
20.045 mm (0.7892 in)
0.004–0.020 mm (0.0002–0.0008 in)
Barrel
0.60 mm (0.0236 in)
0.040–0.080 mm (0.0016–0.0031 in)
Taper
0.80 mm (0.0350 in)
0.030–0.070 mm (0.0012–0.0028 in)
0.05 mm (0.002 in)
35.969–35.984 mm (1.4161–1.4167 in)
0.016–0.046 mm (0.0006–0.0018 in)