Dimensions

Engine Specifications

Cylinder Head
Cylinder Head Flatness - Max Overall 0.076 mm (0.003")
Do Not Resurface Less tan 0.076 mm (0.003")
Resurface 0.076 mm - 0.25 mm (0.003" - 0.010")
Replace Head More Than 0.25 mm (0.010")
Volume 58.9 cc - 60.1 cc (1.5825 oz. - 1.6501 oz.)
Runout 0.05 mm (0.00196")
Valve Seat Diameter Intake 34.066 mm (1.3412")
Exhaust 27.048 mm (1.1436 ")
Intake Valve Guide I.D. 5.921 mm - 5.941 mm (0.2331" - 0.2339")
Exhaust Valve Guide I.D. 5.908 mm - 5.928 mm (0.2326" - 0.2334")
Valve Stem to Valve Guide Clearance Intake 0.024 mm - 0.070 mm (0.000986" - 0.00275")
Exhaust 0.037 mm - 0.082 mm (0.00150" - 0.00320")

Valve Lifter
Clearance in Bore 0.016 mm - 0.058 mm (0.0006" - 0.0023")

Valves
Valve Installed Height - All 24.86 mm - 25.62 mm (0.9787" - 1.0024")
Measure From Top of Valve Stem to Top of Camshaft Housing Mounting Surface Valve
Tip Above Spring Retainer - All 0.602 mm - 0.820 mm (0.0237" - 0.0323")
Intake Valves Valve Face Angle 46 degrees
Valve Seat Angle 45 degrees
Head Diameter 35.5 mm ±0.03 mm (1.3987" ± .0011")
Stem Diameter 5.921 mm - 5.941 mm (0.2331" - 0.2339")
Overall Length 107.290 mm (4.2272")
Stem to Guide Clearance 0.025 mm - 0.069 mm (0.0009" - 0.0025")
Valve Seat Width 0.94 mm - 1.90 mm (0.0370" - 0.0748")
Valve Seat Margin (min.) 0.25 mm (0.0098")
Valve Face Runout 0.038 mm (0.0015")
Valve Tip to Groove Centerline 3.420 mm (0.1346")
Exhaust Valves Valve Face Angle 45.5 degrees
Valve Seat Angle 45 degrees
Head Diameter 28.870 mm - 29.130 mm (1.1366" - 1.1469")
Stem Diameter 5.908 mm - 5.928 mm (0.2326" - 0.2334")
Overall Length 108.17 mm (4.2586")
Stem to Guide Clearance 0.038 mm - 0.082 mm (0.0016" - 0.0032")
Valve Seat Width 0.094 mm - 1.90 mm (0.0037" - 0.0748")
Valve Seat Margin (Min.) 0.25 mm (0.0098")
Valve Face Runout 0.038 mm (0.0015")
Valve Tip to Groove Centerline 3.420 mm (0.1346")

Valve Springs
Valve Spring Pressure Load @ 36.5 mm (1.4370") (Closed) 223-247 N (50-55 lbs.)
Load @ 26.98 mm (1.0622") (Open) 544-596 N (122-133 lbs.)