2008 YAMAHA YZ450F Owners Manual

Page 25 of 188

YAMAHA YZ450F 2008  Owners Manual 2-3
MAINTENANCE SPECIFICATIONS
MAINTENANCE SPECIFICATIONS
ENGINEWheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 313 mm (12.3 in)
Electrical:
Ignition system CDI magneto
Item Standa

Page 26 of 188

YAMAHA YZ450F 2008  Owners Manual 2-4
MAINTENANCE SPECIFICATIONS
Timing chain:
Timing chain type/No. of links 98XRH2010-118M/118 ----
Timing chain adjustment method Automatic ----
Valve, valve seat, valve guide:
Valve clearance (cold)

Page 27 of 188

YAMAHA YZ450F 2008  Owners Manual 2-5
MAINTENANCE SPECIFICATIONS
Stem-to-guide clearance (IN) 0.010–0.037 mm (0.0004–0.0015  in) 0.08 mm (0.003 
in)
Stem-to-guide clearance (EX) 0.020–0.047 mm (0.0008–0.0019  in) 0.10 mm (0.00

Page 28 of 188

YAMAHA YZ450F 2008  Owners Manual 2-6
MAINTENANCE SPECIFICATIONS
Piston off-set 1 mm (0.0394 in) ----
Piston pin bore inside diameter 18.004–18.015 mm (0.7088–0.7093 in) 18.045 mm 
(0.7104 in)
Piston pin outside diameter 17.991–

Page 29 of 188

YAMAHA YZ450F 2008  Owners Manual 2-7
MAINTENANCE SPECIFICATIONS
Air filter oil grade: Foam-air-filter oil or equivalent oil ----
Clutch:
Friction plate thickness 2.92–3.08 mm (0.115–0.121 in) 2.8 mm (0.110 
in)
Quantity 8 ----
Cl

Page 30 of 188

YAMAHA YZ450F 2008  Owners Manual 2-8
MAINTENANCE SPECIFICATIONS
CHASSISSide clearance 0.09–0.17 mm (0.0035–0.0067 in) 0.24 mm (0.009 
in)
Housing and rotor clearance 0.03–0.10 mm (0.0012–0.0039 in) 0.17 mm (0.007 
in)
Bypass

Page 31 of 188

YAMAHA YZ450F 2008  Owners Manual 2-9
MAINTENANCE SPECIFICATIONS
Optional spring Yes←----
Enclosed gas pressure 1,000 kPa (10 kg/cm
2, 
142 psi)←----
Swingarm:
Swingarm free play limit
End ---- 1.0 mm (0.04 
in)
Wheel:
Front wheel

Page 32 of 188

YAMAHA YZ450F 2008  Owners Manual 2-10
TIGHTENING TORQUES
ELECTRICAL
TIGHTENING TORQUES
ENGINE
△- marked portion shall be checked for torque tightening after break-in or before each race.
Item Standard Limit
Ignition system:
Advance