Yamaha Wr 450 F Owners Manual
Here you can view all the pages of manual Yamaha Wr 450 F Owners Manual. The Yamaha manuals for Motorcycle are available online for free. You can easily download all the documents as PDF.
Page 141
4 - 18 ENGCARBURETOR 15. Install: Diaphragm (accelerator pump) 1 Spring 2 O-ring 3 Cover 4 Hose holder (drain hose) 5 Screw (cover) 6 NOTE: Install the diaphragm (accelerator pump) with its mark a facing the spring. 16. Install: Jet needle 1 Collar 2 Spring 3 Needle holder 4 Throttle valve plate 5 To throttle valve 6. 5 6 1 2 3 4 17. Install: Throttle valve assembly 1 Screw (throttle shaft) 2 NOTE: Install the valve lever rollers 3 into the slits a of the throttle valve. 18....
Page 142
4 - 19 ENGCARBURETOR Accelerator pump timing adjustment Adjustment steps: NOTE: In order for the throttle valve height a to achieve the specified value, tuck under the throttle valve plate 1 the rod 2 etc. with the same outer diameter as the specified value. Throttle valve height: 3.1 mm (0.122 in) Fully turn in the accelerator pump adjust- ing screw 3. Check that the link lever 4 has free play b by pushing lightly on it. Gradually turn out the adjusting screw while moving the link lever until it has...
Page 143
4 - 20 ENG 4. Tighten: Screw (air cleaner joint) 1 Screw (carburetor joint) 2 T R..3 Nm (0.3 m · kg, 2.2 ft · lb) T R..3 Nm (0.3 m · kg, 2.2 ft · lb) 5. Install: Throttle cable (pull) 1 Throttle cable (return) 2 6. Adjust: Throttle grip free play Refer to “THROTTLE CABLE ADJUST- MENT” section in the CHAPTER 3. 2 1 T R..4 Nm (0.4 m · kg, 2.9 ft · lb) T R..11 Nm (1.1 m · kg, 8.0 ft · lb) 7. Install: Throttle cable cover 1 Screw (throttle cable cover) 2 2 1 T R..4 Nm (0.4 m · kg, 2.9 ft · lb)...
Page 144
4 - 21 ENG CAMSHAFTS CAMSHAFTS CYLINDER HEAD COVER Extent of removal: 1 Cylinder head cover removal Extent of removal Order Part name Q’ty Remarks CYLINDER HEAD COVER REMOVAL Preparation for removal Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE COVERS” section. Carburetor Refer to “CARBURETOR” section. 1 Spark plug 1 2 Engine upper bracket (right) 1 3 Engine upper bracket (left) 1 4 Cylinder head breather hose 1 5 Oil tank breather hose 1 6 Bolt (cylinder head cover) 2 7 Cylinder...
Page 145
4 - 22 ENG CAMSHAFTS CAMSHAFTS Extent of removal: 1 Camshaft removal Extent of removal Order Part name Q’ty Remarks CAMSHAFTS REMOVAL 1 Timing plug 1 Refer to “REMOVAL POINTS”. 2 Straight plug 1 3 Tensioner cap bolt 1 4 Timing chain tensioner 1 5 Gasket 1 6 Bolt (camshaft cap) 10 7 Camshaft cap 2 8 Clip 2 9 Exhaust camshaft 1 10 Intake camshaft 1 1
Page 146
4 - 23 ENG CAMSHAFTS REMOVAL POINTS Camshaft 1. Remove: Timing plug 1 Straight plug 2 2. Align: “I” mark With stationary pointer. Checking steps: Turn the crankshaft counterclockwise with a wrench. Align the “I” mark a on the rotor with the stationary pointer b on the crankcase cover. When the “I” mark is aligned with the stationary pointer, the piston is at the Top Dead Center (T.D.C.). NOTE: In order to be sure that the piston is at Top Dead...
Page 147
4 - 24 ENG CAMSHAFTS 6. Remove: Clips Exhaust camshaft 1 Intake camshaft 2 NOTE: Attach a wire 3 to the timing chain to prevent it from falling into the crankcase. 1 2 3 INSPECTION Camshaft 1. Inspect: Cam lobes Pitting/scratches/blue discoloration → Replace. 2. Measure: Cam lobes length a and b Out of specification → Replace. Cam lobes length: Intake: a 31.200 ~ 31.300 mm (1.2283 ~ 1.2323 in) : 31.100 mm (1.2244 in) b 22.550 ~...
Page 148
4 - 25 ENG CAMSHAFTS 4. Measure: Camshaft-to-cap clearance Out of specification → Measure cam- shaft journal diameter. Camshaft-to-cap clearance: 0.020 ~ 0.054 mm (0.0008 ~ 0.0021 in) : 0.08 mm (0.003 in) Measurement steps: Install the camshaft onto the cylinder head. Position a strip of Plastigauge ® 1 onto the camshaft. Install the circlip, dowel pins and camshaft caps. T R.. Bolt (camshaft cap): 10 Nm (1.0 m • kg, 7.2 ft • lb) NOTE: Tighten the bolts...
Page 149
4 - 26 ENGCAMSHAFTS Decompression system 1. Check: Decompression system Checking steps: Check that the decompressor cam 1 moves smoothly. Check that the decompressor lever pin 2 projects from the camshaft. Timing chain tensioner 1. Check: While pressing the tensioner rod lightly with fingers, use a thin screwdriver 1 and wind the tensioner rod up fully clockwise. When releasing the screwdriver by pressing lightly with fingers, make sure that the tensioner rod will come out smoothly. If not, replace...
Page 150
4 - 27 ENGCAMSHAFTS Fit the timing chain 3 onto both camshaft sprockets and install the camshafts on the cylinder head. NOTE: The camshafts should be installed onto the cylinder head so that the exhaust cam sprocket punch mark c and the intake cam sprocket punch mark d align with the sur- face of the cylinder head. CAUTION: Do not turn the crankshaft during the camshaft installation. Damage or improper valve timing will result. Install the clips and camshaft caps 4. T R.. Bolt (camshaft cap): 10 Nm...