Yamaha 2004 YP400, Service Manual, Page: 36 / 417

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SPEC
ENGINE SPECIFICATIONS
Valve stem runout ---- 0.01 mm
(0.0004 in)
Valve seat width
Intake 1.0 ~ 1.2 mm (0.0394 ~ 0.0472 in) 1.6 mm
(0.06 in)
Exhaust 1.0 ~ 1.2 mm (0.0394 ~ 0.0472 in) 1.6 mm
(0.06 in)
Valve springs
Free length
Intake 46.45 mm (1.83 in) 44.13 mm
(1.74 in)
Exhaust 46.45 mm (1.83 in) 44.13 mm
(1.74 in)
Installed length (valve closed)
Intake 35.10 mm (1.38 in) ----
Exhaust 35.10 mm (1.38 in) ----
Compressed spring force (installed)
Intake 160.5 ~ 184.7 N at 35.10 mm
(16.37 ~ 18.83 kg at 35.10 mm,
36.08 ~ 41.52 lb at 1.38 in) ----
Exhaust 160.5 ~ 184.7 N at 35.10 mm
(16.37 ~ 18.83 kg at 35.10 mm,
36.08 ~ 41.52 lb at 1.38 in) ----
Spring tilt
Intake ---- 2.0 mm
(0.08 in)
Exhaust ---- 2.0 mm
(0.08 in)
Winding direction (top view)
Intake Clockwise ----
Exhaust Clockwise ----
Item Standard Limit