2007 YAMAHA YZ450F Owners Manual

Page 73 of 650

YAMAHA YZ450F 2007  Owners Manual SPEC
2 - 2 Oil type or grade:
Engine oil (For USA and CDN)
Yamalube 4, SAE10W30 or SAE20W40
Yamalube 4-R, SAE10W50
API service SG type or higher 
JASO standard MA
(Except for USA and CDN)
SAE10W30, SA

Page 74 of 650

YAMAHA YZ450F 2007  Owners Manual SPEC
2 - 3 Transmission:
Primary reduction system Gear
Primary reduction ratio 61/23 (2.652)
Secondary reduction system Chain drive
Secondary reduction ratio 49/13 (3.769)
Transmission type Constant m

Page 75 of 650

YAMAHA YZ450F 2007  Owners Manual SPEC
2 - 4
MAINTENANCE SPECIFICATIONS
ENGINE
Item Standard Limit
Cylinder head:
Warp limit ---- 0.05 mm 
(0.002 in)
Cylinder:
Bore size 95.00 ~ 95.01 mm 
(3.7402 ~ 3.7406 in)----
Out of round limit --

Page 76 of 650

YAMAHA YZ450F 2007  Owners Manual SPEC
2 - 5 Cam chain:
Cam chain type/No. of links 98XRH2010-118M/118 ----
Cam chain adjustment method Automatic ----
Valve, valve seat, valve guide:
Valve clearance (cold) IN 0.10 ~ 0.15 mm 
(0.0039 ~

Page 77 of 650

YAMAHA YZ450F 2007  Owners Manual SPEC
2 - 6 Valve spring:
Free length IN 37.03 mm (1.46 in) 36.03 mm 
(1.42 in)
EX 37.68 mm (1.48 in) 36.68 mm 
(1.44 in)
Set length (valve closed) IN 27.87 mm (1.10 in) ----
EX 27.38 mm (1.08 in) ----

Page 78 of 650

YAMAHA YZ450F 2007  Owners Manual SPEC
2 - 7 Piston rings:
Top ring:
Type Barrel ----
Dimensions (B × T) 1.2 × 3.5 mm (0.05 × 0.14 in) ----
End gap (installed) 0.20 ~ 0.30 mm 
(0.008 ~ 0.012 in)0.55 mm 
(0.022 in)
Side clearance (i

Page 79 of 650

YAMAHA YZ450F 2007  Owners Manual SPEC
2 - 8 Clutch:
Friction plate thickness 2.92 ~ 3.08 mm 
(0.115 ~ 0.121 in)2.8 mm 
(0.110 in)
Quantity 8 ----
Clutch plate thickness 1.5 ~ 1.7 mm (0.059 ~ 0.067 in) ----
Quantity 7 ----
Warp limit

Page 80 of 650

YAMAHA YZ450F 2007  Owners Manual SPEC
2 - 9 Lubrication system:
Oil filter type Paper type ----
Oil pump type Trochoid type ----
Tip clearance “A”0.12 mm or less 
(0.0047 in or less)0.20 mm 
(0.008 in)
Tip clearance “B”0.09 ~