Poor Speed Performance; Overheating; Faulty Brake; Poor Braking Effect - Yamaha 2004 YXR660 Service Manual

FAULTY CLUTCH PERFORMANCE/OVERHEATING/
FAULTY BRAKE/SHOCK ABSORBER MALFUNCTION

POOR SPEED PERFORMANCE

V-belt
• Oil or grease on the V-belt
Primary pulley weight
• Faulty operation
• Worn primary pulley weight
Primary fixed sheave
• Worn primary fixed sheave
EBS00547

OVERHEATING

OVERHEATING
Ignition system
• Improper spark plug gap
• Improper spark plug heat range
• Faulty C.D.I. unit
Fuel system
• Improper carburetor main jet (improper set-
ting)
• Improper fuel level
• Clogged air filter element
Compression system
• Heavy carbon deposit
EBS00550

FAULTY BRAKE

POOR BRAKING EFFECT

Disc brake
• Worn brake pads
• Worn disc
• Air in brake fluid
• Leaking brake fluid
• Faulty master cylinder kit cup
• Faulty caliper kit seal
• Loose union bolt
• Broken brake hose and pipe
• Oily or greasy disc/brake pads
• Improper brake fluid level
EBS00551

SHOCK ABSORBER MALFUNCTION

MALFUNCTION

• Bent or damaged damper rod
• Damaged oil seal lip
• Fatigued shock absorber spring
Primary sliding sheave
• Worn primary sliding sheave
Secondary fixed sheave
• Worn secondary fixed sheave
Secondary sliding sheave
• Worn secondary sliding sheave
Engine oil
• Improper oil level
• Improper oil viscosity
• Inferior oil quality
Brake
• Brake drag
Cooling system
• Low coolant level
• Clogged or damaged radiator
• Damaged or faulty water pump
• Faulty fan motor
• Faulty thermo switch
Oil cooling system
• Clogged or damaged oil cooler
10 - 5
TRBL
SHTG