Yamaha XG250, Service Manual

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TIGHTENING TORQUES
2-14
TIGHTENING TORQUES
GENERAL TIGHTENING TORQUE
SPECIFICATIONS
This chart specifies tightening torques for stan-
dard fasteners with a standard ISO thread pitch.
Tightening torque specifications for special com-
ponents or assemblies are provided for each
chapter of this manual. To avoid warpage, tight-
en multi-fastener assemblies in a crisscross pat-
tern and progressive stages until the specified
tightening torque is reached. Unless otherwise
specified, tightening torque specifications re-
quire clean, dry threads. Components should be
at room temperature.
ENGINE TIGHTENING TORQUES
A. Distance between flats
B. Outside thread diameter
A (nut) B (bolt)
General tightening
torques
Nm m•kg ft•lb
10 mm 6 mm 6 0.6 4.3
12 mm 8 mm 15 1.5 11
14 mm 10 mm 30 3.0 22
17 mm 12 mm 55 5.5 40
19 mm 14 mm 85 8.5 61
22 mm 16 mm 130 13.0 94
Item
Thread
size
Q’ty Tightening torque Remarks
Cylinder head (upper) M8 4 22 Nm (2.2 m•kg, 16 ft•lb)
Cylinder head M8 2 20 Nm (2.0 m•kg, 14 ft•lb)
Camshaft lock plate M6 2 8 Nm (0.8 m•kg, 5.8 ft•lb)
Cylinder head side cover (1 and 2) M55 1/1 18 Nm (1.8 m•kg, 13 ft•lb)
Cylinder head side cover 3 M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Cylinder head breather plate M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Spark plug M12 1 18 Nm (1.8 m•kg, 13 ft•lb)
Cylinder head stud bolt M8 2 15 Nm (1.5 m•kg, 11 ft•lb)
Oil gallery bolt M6 1 7 Nm (0.7 m•kg, 5.1 ft•lb)
Left crankcase cover M6 9 10 Nm (1.0 m•kg, 7.2 ft•lb)
Pickup coil rotor M10 1 60 Nm (6.0 m•kg, 44 ft•lb)
Balancer weight gear M12 1 55 Nm (5.5 m•kg, 40 ft•lb)
Valve clearance adjusting locknut M6 2 14 Nm (1.4 m•kg, 10 ft•lb)
Camshaft sprocket M10 1 60 Nm (6.0 m•kg, 44 ft•lb)
Timing chain tensioner cap bolt M6 1 8 Nm (0.8 m•kg, 5.8 ft•lb)
E
LT
LT