Page 9 of 432

FBU00801
RENSEIGNEMENTS
IMPORTANTS SUR CE MANUEL
LE NON-RESPECT DES AVERTISSEMENTS DON-
NÉS DANS CE MANUEL PEUT ENTRAÎNER DES
BLESSURES GRAVES ET LA MORT.
Les informations particulièrement importantes sont repé-
rées par les notations suivantes:_ Le symbole de danger incite à ÊTRE VIGILANT, CAR
LA SÉCURITÉ EST EN JEU!
AVERTISSEMENT
_ Le non-respect des instructions données sous un
AVERTISSEMENT peut entraîner des blessures gra-ves ou la mort
du pilote, d’un tiers ou d’une personne
inspectant ou réparant le véhicule.
SBU00801
INFORMACIÓN IMPORTANTE
SOBRE ESTE MANUAL
LA INOBSERVANCIA DE LAS ADVERTENCIAS
CONTENIDAS EN ESTE MANUAL PUEDE ACA-
RREAR LESIONES GRAVES O INCLUSO MOR-
TALES.
La información de especial importancia se señala
en este manual con las siguientes notaciones:El símbolo de alerta de seguridad significa ¡ATEN-
CIÓN! ¡MANTÉNGASE ALERTA! ¡PELIGRA SU
SEGURIDAD!
ADVERTENCIA
La inobservancia de las instrucciones de ADVER-
TENCIA puede ser causa de lesiones graves o mor-tales
para el usuario de la máquina, las personas si-
tuadas en sus proximidades o los técnicos
encargados de su inspección o reparación.
U5LP64.book Page 2 Thursday, April 1, 2004 4:53 PM
Page 10 of 432
CAUTION:
A CAUTION indicates special precautions that
must be taken to avoid damage to the machine.NOTE:NOTE:A NOTE provides key information to make proce-
dures easier or clearer.
U5LP64.book Page 3 Thursday, April 1, 2004 4:53 PM
Page 11 of 432
ATTENTION:_ Un ATTENTION indique les précautions particulières à
prendre pour éviter d’endommager le véhicule.N.B.:N.B.: Un N.B. fournit les renseignements nécessaires à la clari-
fication et à la simplification des divers travaux.
AT E N C I O N :
Los avisos de ATENCION indican precauciones es-
peciales que deben adoptarse para evitar que la má-
quina sufra daños.NOTA:NOTA: Las NOTAS contienen información importante para
facilitar o aclarar los procedimientos.
U5LP64.book Page 4 Thursday, April 1, 2004 4:53 PM
Page 12 of 432
EBU00111
2-IMPORTANT NOTICE
This ATV is designed and manufactured for use on
UNPAVED surfaces only. It is unsafe to operate
this ATV on any paved surface, paved street,
paved road or motorway.
Please check your local riding laws and regula-
tions before operating this ATV.
EBU01056
YFM660RT
OWNER’S MANUAL
©2004 by Yamaha Motor Co., Ltd.
1st edition, March 2004
All rights reserved. Any reprinting or
unauthorized use without the written
permission of Yamaha Motor Co., Ltd.
is expressly prohibited.
Printed in Japan.
U5LP64.book Page 1 Thursday, April 1, 2004 4:53 PM
Page 13 of 432

FBU00111
REMARQUE IMPORTANTE
Ce véhicule est conçu et fabriqué pour une utilisation sur
surfaces NON REVÊTUES uniquement. La conduite de
ce véhicule sur les surfaces ou les routes revêtues est dan-
gereuse.
Prendre connaissance des règlements locaux avant de
conduire ce véhicule.
FBU01056
YFM660RT
MANUEL DU PROPRIÉTAIRE
©2004 par Yamaha Motor Co., Ltd.
1
re édition, mars 2004
Tous droits réservés. Toute réimpression ou
utilisation non autorisée sans la permission
écrite de la Yamaha Motor Co., Ltd.
est formellement interdite.
Imprimé au Japon
SBU00111
AVISO IMPORTANTE
Este ATV ha sido fabricado y diseñado únicamente
para su utilización en terrenos SIN PAVIMENTAR.
Por lo tanto, es peligroso, circular con el ATV por su-
perficies pavimentadas, calles pavimentadas, carre-
teras pavimentadas o autopistas pavimentadas.
Se ruega consultar las leyes y reglamentaciones lo-
cales sobre vehículos motorizados antes de usar el
ATV.
SBU01056
YFM660RT
MANUAL DEL PROPIETARIO
©2004 por Yamaha Motor Co., Ltd.
1ª edición, marzo 2004
Reservados todos los derechos. Queda
expresamente prohibida cualquier reimpresión
o uso no autorizado sin el consentimiento por
escrito de Yamaha Motor Co., Ltd.
Impreso en Japón.
U5LP64.book Page 2 Thursday, April 1, 2004 4:53 PM
Page 14 of 432

EBU00015
1-CONTENTS
LOCATION OF THE WARNING
AND SPECIFICATION LABELS ............. 1-1
SAFETY INFORMATION ......................... 2-1
DESCRIPTION AND MACHINE
IDENTIFICATION ................................... 3-1
Identification number records .............. 3-3
Key identification number .................... 3-5
Vehicle identification number .............. 3-5
Model label ........................................... 3-7
CONTROL FUNCTIONS ........................ 4-1
Main switch........................................... 4-1
Indicator and warning lights ................. 4-3
Handlebar switches ........................... 4-11
Throttle lever ..................................... 4-15
Speed limiter ...................................... 4-17
Clutch lever ....................................... 4-19
Brake lever ......................................... 4-19
Brake pedal ........................................ 4-21
Parking brake lever ............................ 4-23
Shift pedal ......................................... 4-27
Reverse knob .................................... 4-27
1234
Fuel tank cap .................................... 4-29
Fuel cock............................................ 4-29
Starter (choke) .................................. 4-31
Seat.................................................... 4-33
Front shock absorber adjustment ...... 4-35
Rear shock absorber adjustment ....... 4-37
PRE-OPERATION CHECKS .................. 5-1
Front and rear brakes .......................... 5-5
Fuel ...................................................... 5-9
Engine oil ........................................... 5-13
Coolant............................................... 5-15
Chain ................................................. 5-17
Throttle lever ...................................... 5-19
Fittings and fasteners......................... 5-19
Lights ................................................. 5-19
Switches............................................. 5-19
Tires .................................................. 5-21
How to measure tire pressure ........... 5-25
Tire wear limit .................................... 5-27
5
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Page 15 of 432

OPERATION ...........................................6-1
Starting a cold engine ..........................6-3
Starting a warm engine ........................6-9
Warming up...........................................6-9
Reverse knob operation and
reverse driving ..................................6-11
Shifting ................................................6-15
To start out and accelerate .................6-17
To decelerate ......................................6-21
Engine break-in ...................................6-23
Parking ...............................................6-27
Parking on a slope ..............................6-29
Accessories and loading ....................6-33
RIDING YOUR ATV..................................7-1
Getting to know your ATV .....................7-3
Ride with care and good judgement .....7-5
Be careful where you ride ...................7-27
Turning your ATV ................................7-41
Climbing uphill.....................................7-47
Riding downhill ....................................7-57
Crossing a slope .................................7-61
Crossing through shallow water ..........7-65
Riding over rough terrain ....................7-69
Sliding and skidding ............................7-71
What to do if .......................................7-75
What to do ..........................................7-75
67
PERIODIC MAINTENANCE AND
ADJUSTMENT ........................................ 8-1
Owner’s manual and tool kit ................. 8-3
Periodic maintenance/lubrication.......... 8-7
Panel removal and installation ........... 8-17
Engine oil and oil filter cartridge ......... 8-19
Cooling system ................................... 8-35
Changing the coolant.......................... 8-39
Spark plug inspection ......................... 8-47
Air filter element cleaning ................... 8-53
Carburetor adjustment ........................ 8-59
Idle speed adjustment ........................ 8-61
Throttle lever adjustment ................... 8-63
Valve clearance adjustment .............. 8-65
Front and rear brake pad inspection... 8-67
Brake fluid level inspection ................. 8-69
Brake fluid replacement ...................... 8-73
Front brake lever free play.................. 8-75
Brake pedal height adjustment ........... 8-77
Parking brake adjustment ................... 8-79
Adjusting the rear brake light switch ... 8-83
Clutch lever free play adjustment ...... 8-85
Drive chain slack check ...................... 8-87
Drive chain slack adjustment .............. 8-89
Lubricating the drive chain ................. 8-91
Cable inspection and lubrication ........ 8-95
8
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Page 16 of 432

Brake and shift pedal/brake and
clutch lever lubrication ..................... 8-95
Front upper and lower arm pivot
lubrication ......................................... 8-97
Rear arm pivot lubrication .................. 8-99
Wheel removal ................................. 8-103
Wheel installation ............................ 8-105
Battery ............................................. 8-107
Battery maintenance ....................... 8-111
Fuse replacement ............................ 8-113
Replacing a headlight bulb ............... 8-115
Tail/brake light bulb replacement ..... 8-125
Troubleshooting ............................... 8-127
Troubleshooting chart ...................... 8-129
CLEANING AND STORAGE .................. 9-1
A. Cleaning .......................................... 9-1
B. Storage ........................................... 9-7
SPECIFICATIONS ................................ 10-1
CONVERSION TABLE .......................... 11-1
91011U5LP64.book Page 3 Thursday, April 1, 2004 4:53 PM