2009 Yamaha YZ450F(Y) Owner's Service Manual PDF (P/N 34P-28199-80-E0)

The 2009 Yamaha YZ450F(Y) owner's service manual, publication 34P-28199-80-E0, is Yamaha's first edition from May 2008. It covers the USA, Canadian, European, Australian, New Zealand, and South African versions of this motocross racing machine.

• Engine repair: Cylinder-head and valve service, camshaft timing, piston inspection, engine removal, crankcase separation, and crankshaft installation.

• Clutch and transmission: Clutch disassembly and wear checks, kickstarter service, and inspection of transmission gears, shift forks, and the shift cam.

• Fuel and cooling: Carburetor overhaul, accelerator-pump timing, radiator pressure testing, and water-pump inspection and seal replacement.

• Chassis service: Brake caliper and master-cylinder repair, hydraulic bleeding, fork disassembly, steering bearings, swingarm linkage, and rear shock spring service.

• Electrical diagnosis: Wiring diagram, ignition troubleshooting chart, coil and switch tests, and throttle position sensor inspection and adjustment.

• Race setup: Carburetor setting charts, jet and needle options, sprocket selection, and suspension tuning linked to riding symptoms.

The repair and valve-clearance sections are written for readers with existing Yamaha servicing knowledge and skills, including dealer mechanics and service engineers.

Maintenance, Engine Repair, and Transmission

The manual is organized across seven core sections. Initial chapters outline vehicle identification, machine parts, and preparation for disassembly, with race-based maintenance schedules, pre-operation checks, and cleaning and storage procedures.

Cylinder head and valve gear: Valve-pad selection tables and camshaft alignment illustrations accompany valve-guide, cylinder-head, and piston work. The cylinder-head installation procedure includes staged torque and angle tightening. Uneven camshaft-cap tightening can damage the cylinder head, caps, and camshafts.

Lower end and drivetrain: Crankshaft runout checks and transmission exploded views support internal inspection, including gear engagement surfaces and shift-fork condition. The special-tool list identifies crankcase separator YU-A9642 / 90890-04152 and the crankshaft installation tools used during reassembly.

Oil-pump inspection includes rotor clearances. Lubrication diagrams show oil paths serving the crankshaft, transmission shafts, and camshafts, while component-specific torque tables and wear limits accompany the repair information.

Carburetor Service and Cooling

Carburetor coverage extends to the float and needle valve, hot-start plunger, accelerator-pump diaphragm, and throttle mechanism. The tuning chapter relates jetting changes to atmospheric conditions and throttle opening, with symptom-based examples for poor acceleration and throttle response.

Radiator-cap and cooling-system pressure tests accompany radiator removal and water-pump seal service. Follow the manual's precautions for hot, pressurized coolant before cooling-system work.

Brakes, Suspension, and Track Settings

The brake chapters cover caliper pistons, seals, and master-cylinder cups. Chassis procedures also address drive-chain wear, wheel bearings, steering-head adjustment, and swingarm linkage bearings.

Front-fork exploded views accompany seal, bushing, and damper service. Suspension setting charts relate handling symptoms to spring selection and damping adjustments. USA/Canada settings are distinguished from other-market settings, including fork oil quantities and standard damping positions.

Rear shock scope: Removal, spring replacement, and bearing service are covered. The high-pressure nitrogen damper cylinder and reservoir must not be dismantled; this section does not provide an internal shock-overhaul procedure.

Ignition and Throttle Position Sensor Diagnosis

The wiring diagram identifies wire colors and connector terminals. Separate ignition and throttle position sensor inspection charts organize fault checks, supported by connector-test illustrations and electrical specifications.

The no-spark chart helps distinguish connection, switch, ignition-coil, and CDI-magneto faults before considering CDI-unit replacement. The throttle position sensor section also warns that shorting test connections can damage electrical components.

A Preview of Coolant Capacity and Cylinder-Head Specifications

These examples represent a small selection of the service specifications included in the manual.

Cooling-system capacity is 0.99 L, including all coolant routes. Valve clearance is specified with the engine cold: 0.10–0.15 mm for the intake valves and 0.20–0.25 mm for the exhaust valves.

For the four main cylinder-head bolts, the final angle stage totals 180° within the documented multistage torque-and-angle tightening procedure.

PDF Search, Bookmarks, and Page Coverage

Search and navigation: Body text is searchable, but some illustrated tables, including the valve-pad selection charts, are not text-searchable. Section bookmarks provide navigation; chapter-level entries return to the contents page, and the top contents bookmark has no valid destination. Small wiring and connector labels are readable when enlarged.

Supplied as one printable English PDF with 187 pages: seven opening pages covering the front cover, publication information, introductory material, and contents; 178 technical pages; one blank page; and the back cover. All are included in the total.