System Specifications

The cylinder head bolts must be discarded and new bolts installed. They are tighten-to-yield designed and cannot be reused.
Cylinder head gasket surface flatness 0.05 mm (0.002 inch) in any 150 mm x 150 mm (6.0 in x 6.0 inch) area
Combustion chamber volume 51.5-52.5 cc (3.14-3.20 cu inch)
Valve arrangement (front to rear) - LH E-I-E-I-E-I-E-I
Valve arrangement (front to rear) - RH I-E-I-E-I-E-I-E
Valve guide bore diameter 7.044-7.015 mm (0.2773-0.2762 inch)
Valve stem diameter - intake 6.995-6.975 mm (0.2754-0.2746 inch)
Valve stem diameter - exhaust 6.970-6.949 mm (0.2744-0.2736 inch)
Valve stem-to-guide clearance - intake 0.020-0.069 mm (0.0008-0.0027 inch)
Valve stem-to-guide clearance - exhaust 0.045-0.095 mm (0.0018-0.0037 inch)
Valve head diameter - intake 44.5 mm (1.751 inch)
Valve head diameter - exhaust 34.0 mm (1.338 inch)
Valve face runout 0.05 mm (0.0019 inch)
Valve face angle 45.25-45.75 degrees
Valve seat width 1.9-2.1 mm (0.0748-0.0827 inch)
Valve seat runout (T.I.R.) max. 0.025 mm (0.0010 inch)
Valve seat angle 45.50 degrees
Valve spring free length 49.55 mm (1.9508 inch)
Valve spring squareness 2 degrees
Valve spring compression pressure 587.14 N @ 28.02 mm (131.994 lb @ 1.1032 inch)
Valve spring installed height 39.7-40.3 mm (1.5630-1.5866 inch)
Valve spring installed pressure - valve open 587.165 N @ 27.99 mm (132 lb @ 1.102 inch)
Valve spring installed pressure - valve closed 244.652 N @ 39.98 mm (55 lb @ 1.574 inch)
Roller follower ratio 1.75:1

For torque specifications, refer to the service procedure.