Overheating; Poor Braking Performance; Unstable Handling; Faulty Lighting Or Signaling System - Yamaha 2009 YFM25RY Service Manual

• Incorrect oil level
• Incorrect oil viscosity (low)
• Deteriorated oil
Clutch drags
1. Clutch
• Unevenly tensioned clutch springs
• Warped pressure plate
• Bent clutch plate
• Swollen friction plate
• Bent clutch push rod
• Damaged clutch boss
• Burnt primary driven gear bushing
• Loose clutch boss nut
2. Engine oil
• Incorrect oil level
• Incorrect oil viscosity (high)
• Deteriorated oil
EAS28590

OVERHEATING

Engine
1. Cylinder head and piston
• Heavy carbon buildup
2. Engine oil
• Incorrect oil level
• Incorrect oil viscosity
• Inferior oil quality
Fuel system
1. Carburetor
• Incorrect main jet setting
• Incorrect fuel level
• Damaged or loose carburetor joint
2. Air filter
• Clogged air filter element
Chassis
1. Brake(s)
• Dragging brake
Electrical system
1. Spark plug
• Incorrect spark plug gap
• Incorrect spark plug heat range
2. Ignition system
• Faulty ignitor unit
EAS28620

POOR BRAKING PERFORMANCE

• Worn brake pad
• Worn brake disc
• Air in hydraulic brake system
• Leaking brake fluid
TROUBLESHOOTING
• Faulty brake caliper kit
• Faulty brake caliper seal
• Loose union bolt
• Damaged brake hose
• Oil or grease on the brake disc
• Oil or grease on the brake pad
• Incorrect brake fluid level
EAS28670

UNSTABLE HANDLING

1. Handlebar
• Bent or improperly installed handlebar
2. Steering
• Incorrect toe-in
• Improperly installed steering stem
• Bent tie-rods
• Bent steering stem
• Damaged ball bearing or bearing race
• Deformed steering knuckles
3. Swingarm
• Worn bearing or bushing
• Bent or damaged swingarm
4. Rear shock absorber assembly
• Faulty rear shock absorber spring
• Leaking oil or gas
5. Tire(s)
• Uneven tire pressures (front and rear)
• Incorrect tire pressure
• Uneven tire wear
6. Wheel(s)
• Incorrect wheel balance
• Deformed wheel
• Damaged wheel bearing
• Bent or loose wheel axle
• Excessive wheel runout
7. Frame
• Bent frame
• Damaged steering head pipe
• Improperly installed bearing race
EAS28710
FAULTY LIGHTING OR SIGNALING SYS-
TEM
Headlight does not come on
• Wrong headlight bulb
• Too many electrical accessories
• Hard charging
• Incorrect connection
• Improperly grounded circuit
• Poor contacts (main or light switch)
• Burnt-out headlight bulb
Headlight bulb burnt out
• Wrong headlight bulb
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