Poor Braking Performance; Faulty Front Fork Legs; Unstable Handling; Faulty Lighting Or Signaling System - Yamaha SR400 2014 Service Manual

EAS28640

POOR BRAKING PERFORMANCE

1. Disc brake
• Worn brake pad
• Worn brake disc
• Air in hydraulic brake system
• Leaking brake fluid
• 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
2. Drum brake
• Worn brake shoe
• Worn or rusty brake drum
• Incorrect brake pedal position (above the top
of the rider footrest)
• Incorrect brake pedal free play
• Incorrect brake camshaft lever position
• Incorrect brake shoe position
• Damaged or fatigued brake shoe spring
• Oil or grease on the brake shoe
• Oil or grease on the brake drum
• Broken brake torque rod
EAS28660

FAULTY FRONT FORK LEGS

Leaking oil
• Bent, damaged or rusty inner tube
• Cracked or damaged outer tube
• Improperly installed oil seal
• Damaged oil seal lip
• Incorrect oil level (high)
• Loose damper rod assembly bolt
• Damaged damper rod assembly bolt copper
washer
• Cracked or damaged cap bolt O-ring
Malfunction
• Bent or damaged inner tube
• Bent or damaged outer tube
• Damaged fork spring
• Worn or damaged outer tube bushing
• Bent or damaged damper rod
• Incorrect oil viscosity
• Incorrect oil level
EAS28690

UNSTABLE HANDLING

1. Handlebar
• Bent or improperly installed handlebar
2. Steering head components
• Improperly installed upper bracket
• Improperly installed lower bracket
TROUBLESHOOTING
(improperly tightened ring nut)
• Bent steering stem
• Damaged ball bearing or bearing race
3. Front fork leg(s)
• Uneven oil levels (both front fork legs)
• Unevenly tensioned fork spring (both front
fork legs)
• Broken fork spring
• Bent or damaged inner tube
• Bent or damaged outer tube
4. Swingarm
• Worn bearing or bushing
• Bent or damaged swingarm
5. Rear shock absorber assembly(-ies)
• Faulty rear shock absorber spring
• Leaking oil
6. Tire(s)
• Uneven tire pressures (front and rear)
• Incorrect tire pressure
• Uneven tire wear
7. Wheel(s)
• Incorrect wheel balance
• Broken or loose spoke
• Damaged wheel bearing
• Bent or loose wheel axle
• Excessive wheel runout
8. Frame
• Bent frame
• Damaged steering head pipe
• Improperly installed bearing race
EAS28710

FAULTY LIGHTING OR SIGNALING SYSTEM

Headlight does not come on
• Wrong headlight bulb
• Too many electrical accessories
• Hard charging
• Incorrect connection
• Improperly grounded circuit
• Poor contacts (main or dimmer switch)
• Burnt-out headlight bulb
Headlight bulb burnt out
• Wrong headlight bulb
• Faulty battery
• Faulty rectifier/regulator
• Improperly grounded circuit
• Faulty main switch
• Faulty dimmer switch
• Headlight bulb life expired
The tail/brake light does not come on
• Wrong tail/brake light bulb
• Too many electrical accessories
• Incorrect connection
• Improperly grounded circuit
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