Yamaha XT660R, Service Manual

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SPEC
ENGINE SPECIFICATIONS
Valve-stem-to-valve-guide clearance
Intake 0.010 ~ 0.037 mm (0.0004 ~ 0.0015 in) 0.08 mm
(0.0031 in)
Exhaust 0.025 ~ 0.052 mm (0.0010 ~ 0.0020 in) 0.10 mm
(0.0039 in)
Valve stem runout ---- 0.010 mm
(0.0004 in)
Valve seat width
Intake 1.00 ~ 1.20 mm (0.0394 ~ 0.0472 in) 1.6 mm
(0.06 in)
Exhaust 1.00 ~ 1.20 mm (0.0394 ~ 0.0472 in) 1.6 mm
(0.06 in)
Valve springs
Free length
Intake 40.38 mm (1.59 in) 38.36 mm
(1.51 in)
Exhaust 40.38 mm (1.59 in) 38.36 mm
(1.51 in)
Installed length (valve closed)
Intake 35.00 mm (1.38 in) ----
Exhaust 35.00 mm (1.38 in) ----
Compressed spring force (installed)
Intake 171 ~ 197 N
(17.44 ~ 20.09 kg, 38.44 ~ 44.29 lb) ----
Exhaust 171 ~ 197 N
(17.44 ~ 20.09 kg, 38.44 ~ 44.29 lb) ----
Spring tilt
Intake ---- 2.5°/1.8 mm
(2.5°/0.071 in)
Exhaust ---- 2.5°/1.8 mm
(2.5°/0.071 in)
Winding direction (top view)
Intake Clockwise ----
Exhaust Clockwise ----
Item Standard Limit