Yamaha YZ250F(X), Owner'S Service Manual

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2-5
MAINTENANCE SPECIFICATIONS
Stem runout limit ---- 0.01 mm
(0.0004 in)
Valve seat width (IN) 0.9–1.1 mm (0.0354–0.0433 in) 1.6 mm (0.0630
in)
Valve seat width (EX) 0.9–1.1 mm (0.0354–0.0433 in) 1.6 mm (0.0630
in)
Valve spring:
Free length (IN) 37.81 mm (1.49 in) 36.81 mm (1.45
in)
Free length (EX) 37.54 mm (1.48 in) 36.54 mm (1.44
in)
Set length (valve closed) (IN) 29.13 mm (1.15 in) ----
Set length (valve closed) (EX) 29.30 mm (1.15 in) ----
Compressed force (installed) (IN) 99–114 N at 29.13 mm (9.9–11.4 kg at
29.13 mm, 22.27–25.57 lb at 1.15 in) ----
Compressed force (installed) (EX) 126–144 N at 29.30 mm (12.6–14.4 kg at
29.30 mm, 28.44–32.41 lb at 1.15 in) ----
Tilt limit* (IN) ---- 2.5°/1.7 mm
(2.5°/0.067 in)
Tilt limit* (EX) ---- 2.5°/1.6 mm
(2.5°/0.063 in)
Direction of winding (top view) (IN) Clockwise ----
Direction of winding (top view) (EX) Clockwise ----
Piston:
Piston to cylinder clearance 0.030–0.055 mm (0.0012–0.0022 in) 0.1 mm (0.004
in)
Piston size "D" 76.955–76.970 mm (3.0297–3.0303 in) ----
Measuring point "H" 8 mm (0.31 in) ----
Piston off-set 0.5 mm (0.020 in)/IN-side ----
Piston pin bore inside diameter 16.002–16.013 mm (0.6300–0.6304 in) 16.043 mm
(0.6316 in)
Item Standard Limit