Yamaha YFM660FS User manual

5KM-28199-12LIT-11626-17-14
READ THIS MANUAL CAREFULLY!
It contains important safety information.
This ATV should not be ridden by anyone under 16 years of age.
WARNING
YFM660FS
OWNER’S MANUAL
PRINTED IN JAPAN
2003.04-7.1×1 CR
(E)
PRINTED ON RECYCLED PAPER
YAMAHA MOTOR CO., LTD.
EBU00438
LOCATE AND READ OWNER’S MANUAL. FOLLOW ALL INSTRUCTIONS AND WARNINGS.
(For replacement manual, call 1-800-532-1558)
WARNING
ALWAYS:
use proper riding techniques to avoid
vehicle overturns on hills and rough
terrain and in turns.
avoid paved surfaces-pavement may
seriously affect handling and control.
Improper ATV use can result in SEVERE INJURY or DEATH.
NEVER operate:
without proper training or instruction.
at speeds too fast for your skills or the
conditions.
on public roads-a collision can occur with
another vehicle.
with a passenger-passengers affect
balance and steering and increase risk
of losing control.
ALWAYS USE
AN APPROVED
HELMET AND
PROTECTIVE GEAR
NEVER USE
ON PUBLIC
ROADS
NEVER CARRY
PASSENGERS
NEVER USE
WITH DRUGS
OR ALCOHOL
B
E
E
R
B
EE
R

EBU00776

EBU00941
1-
INTRODUCTION
Congratulations on your purchase of the Yamaha YFM660F. It represents the result of many
years of Yamaha experience in the production of fine sporting, touring, and pace-setting racing
machines. With the purchase of this Yamaha, you can now appreciate the high degree of crafts-
manship and reliability that have made Yamaha a leader in these fields.
This manual will provide you with a good basic understanding of the features and operation of this
ATV. This manual includes important safety information. It provides information about
special techniques and skills necessary to ride your ATV. It also includes basic maintenance
and inspection procedures. If you have any questions regarding the operation or maintenance of
your ATV, please consult a Yamaha dealer.
AN IMPORTANT SAFETY MESSAGE:
●READ THIS MANUAL TOGETHER WITH TIPS FOR THE ATV RIDER CAREFULLY AND
COMPLETELY BEFORE OPERATING YOUR ATV. MAKE SURE YOU UNDERSTAND ALL
INSTRUCTIONS.
●PAY CLOSE ATTENTION TO THE WARNING AND CAUTION LABELS ON THE ATV.
●NEVER OPERATE AN ATV WITHOUT PROPER TRAINING OR INSTRUCTION. FREE
TRAINING IS AVAILABLE TO ANYONE WHO BUYS A NEW ATV. CALL 1-800-887-2887
FOR MORE INFORMATION.
●THIS ATV, AND ANY OTHER ATV OVER 90cc, SHOULD NOT BE RIDDEN BY ANYONE
UNDER 16 YEARS OF AGE.
U5KM12.book Page 1 Wednesday, March 26, 2003 3:50 PM

EBU00801
1-
IMPORTANT MANUAL INFORMATION
FAILURE TO FOLLOW THE WARNINGS CONTAINED IN THIS MANUAL CAN RESULT IN
SERIOUS INJURY OR DEATH.
Particularly important information is distinguished in this manual by the following notations:
The Safety Alert Symbol means ATTENTION! BECOME ALERT!
YOUR SAFETY IS INVOLVED!
WARNING
Failure to follow WARNING instructions could result in severe
injury or death to the machine operator, a bystander or a person
inspecting or repairing the machine.
CAUTION:
A CAUTION indicates special precautions that must be taken to
avoid damage to the machine.
NOTE:
A NOTE provides key information to make procedures easier or clearer.
U5KM12.book Page 1 Wednesday, March 26, 2003 3:50 PM

AFFIX DEALER
LABEL HERE
EBU00011
IMPORTANT NOTICE
This machine is designed and manufactured for OFF-ROAD use only. It is illegal and unsafe to
operate this machine on any public street, road or highway.
This machine complies with all applicable OFF-ROAD noise level and spark arrester laws and
regulations in effect at the time of manufacture.
Please check your local riding laws and regulations before operating this machine.
EBU00981
YFM660FS
OWNER’S MANUAL
©2003 by Yamaha Motor Corporation,
U.S.A.
1st edition, March 2003
All rights reserved.
Any reprinting or unauthorized use
without the written permission
of Yamaha Motor Corporation, U.S.A.
is expressly prohibited.
Printed in Japan.
P/N LIT-11626-17-14
U5KM12.book Page 2 Wednesday, March 26, 2003 3:50 PM

EBU00014
WARNING
Indicates a potential hazard that could
result in serious injury or death.
CONTENTS
LOCATION OF THE WARNING
AND SPECIFICATION LABELS....... 1-1
SAFETY INFORMATION.................. 2-1
DESCRIPTION AND MACHINE
IDENTIFICATION ............................. 3-1
Identification number records.......... 3-2
Key identification number................ 3-2
Vehicle identification number .......... 3-3
Model label ...................................... 3-3
1
2
3
CONTROL FUNCTIONS...................4-1
Main switch ......................................4-1
Indicator and warning lights.............4-2
Speedometer unit ............................4-4
Fuel gauge .......................................4-6
Handlebar switches .........................4-6
Throttle lever ..................................4-13
Speed limiter ..................................4-14
Front brake lever............................4-15
Rear brake pedal and lever ...........4-15
Drive select lever ...........................4-16
Recoil starter..................................4-16
Fuel tank cap .................................4-17
Fuel cock........................................4-18
Starter (choke) ...............................4-19
Seat................................................4-20
Storage compartment ....................4-21
Front carrier ...................................4-21
Rear carrier ....................................4-21
Front and rear shock absorber
adjustment ...................................4-22
Auxiliary DC jack............................4-24
4
U5KM12.book Page 1 Wednesday, March 26, 2003 3:50 PM

PRE-OPERATION CHECKS ........... 5-1
Front and rear brakes ..................... 5-3
Fuel ................................................. 5-5
Engine oil ........................................ 5-7
Final gear oil.................................... 5-7
Differential gear oil .......................... 5-8
Coolant............................................ 5-9
Throttle lever ................................. 5-10
Fittings and fasteners.................... 5-10
Lights............................................. 5-10
Switches........................................ 5-10
Tires .............................................. 5-11
How to measure tire pressure....... 5-13
Tire wear limit................................ 5-14
OPERATION..................................... 6-1
Starting a cold engine ..................... 6-1
Starting a warm engine................... 6-3
Warming up..................................... 6-3
Drive select lever operation and
reverse driving............................... 6-4
Engine break-in............................... 6-7
Parking ............................................ 6-8
Parking on a slope...........................6-9
Accessories and loading ............... 6-10
RIDING YOUR ATV .......................... 7-1
Getting to know your ATV ............... 7-3
Ride with care and good
judgement...................................... 7-4
Be careful where you ride.............. 7-16
Turning your ATV .......................... 7-22
Climbing uphill ............................... 7-24
Riding downhill .............................. 7-30
Crossing a slope............................7-32
Crossing through shallow water .... 7-34
Riding over rough terrain............... 7-37
Sliding and skidding....................... 7-38
What to do if................................... 7-40
What to do ..................................... 7-40
5
6
7
U5KM12.book Page 2 Wednesday, March 26, 2003 3:50 PM

PERIODIC MAINTENANCE AND
ADJUSTMENT.................................. 8-1
Owner’s manual and tool kit............ 8-1
Periodic maintenance/
lubrication ...................................... 8-3
Panel removal and installation ........ 8-5
Engine oil and oil filter cartridge .... 8-12
Final gear oil .................................. 8-17
Differential gear oil......................... 8-19
Cooling system.............................. 8-21
Axle boots...................................... 8-26
Spark plug inspection.................... 8-27
Air filter element cleaning.............. 8-30
Spark arrester cleaning ................. 8-33
Carburetor adjustment................... 8-35
Idle speed adjustment ................... 8-36
Valve clearance adjustment.......... 8-36
Throttle lever adjustment............... 8-37
Front brake pad check .................. 8-37
Rear brake pad inspection ............ 8-38
Inspecting the brake fluid level...... 8-38
Brake fluid replacement................. 8-40
Front brake lever free play ............ 8-41
Rear brake lever and pedal
adjustment ...................................8-42
Adjusting the rear brake light
switch ...........................................8-44
Cable inspection and lubrication....8-44
Brake lever and brake pedal
lubrication.....................................8-45
Rear knuckle upper and lower
pivot lubrication ............................8-46
Wheel removal...............................8-46
Wheel installation...........................8-47
Battery............................................8-48
Battery maintenance......................8-49
Fuse replacement ..........................8-49
Replacing a headlight bulb ............8-51
Headlight beam adjustment...........8-52
Tail/brake light bulb
replacement .................................8-53
Troubleshooting .............................8-53
Troubleshooting charts ..................8-55
8
U5KM12.book Page 3 Wednesday, March 26, 2003 3:50 PM

CLEANING AND STORAGE............ 9-1
A. Cleaning...................................... 9-1
B. Storage ....................................... 9-3
SPECIFICATIONS.......................... 10-1
NOISE REGULATION.................... 11-1
MAINTENANCE RECORD ............ 12-1
ATV LIMITED WARRANTY ........... 13-1
YAMAHA EXTENDED SERVICE
(Y.E.S.) ........................................... 14-1
9
10
11
12
13
14
U5KM12.book Page 4 Wednesday, March 26, 2003 3:50 PM

1-1
EBU00464
LOCATION OF THE WARNING AND
SPECIFICATION LABELS
U5KM12.book Page 1 Wednesday, March 26, 2003 3:50 PM

1-2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Read and understand all of the labels on your
machine. They contain important information
for safe and proper operation of your ATV.
Never remove any labels from your ATV. If a
label becomes difficult to read or comes off, a
replacement label is available from your
Yamaha dealer.
85 kg {187 lbs}
4WV-24877-A0
LOAD LIMIT
PULLING LOAD:
TONGUE WEIGHT:
5390 N (550 kgf)
1212 lbf
147 N ( 15 kgf)
33 lbf
5KM-2151K-00
MAXIMUM LOADING LIMIT
4
WARNING
NEVER sit here.
3MX-24875-A0
12
3
U5KM12.book Page 2 Wednesday, March 26, 2003 3:50 PM

1-3
56
7
U5KM12.book Page 3 Wednesday, March 26, 2003 3:50 PM

1-4
89
0
UNDER
WARNING
5FE-21697-01
NEVER operate this ATV if you are
under age 16.
Operating this ATV if you are under
the age of 16 increases your chance
of severe injury or death.
WARNING
Turning the ATV in 4WD-LOCK(“DIFF. LOCK”)
takes more effort.
Operate at a slow speed and allow
extra time and distance for maneuvers
to avoid loss of control.
5KM-21558-00
U5KM12.book Page 4 Wednesday, March 26, 2003 3:50 PM

2-1
SAFETY INFORMATION
EBU01129
AN ATV IS NOT A TOY AND CAN BE HAZARDOUS TO OPERATE. An ATV handles differently
from other vehicles including motorcycles and cars. A collision or rollover can occur quickly, even
during routine maneuvers such as turning and riding on hills or over obstacles, if you fail to take
proper precautions.
SEVERE INJURY OR DEATH can result if you do not follow these instructions:
●Read this manual and all labels carefully and follow the operating procedures described.
●Never operate an ATV without proper training or instruction. Take a Training Course. Begin-
ners should receive training from a certified instructor. Contact an authorized ATV dealer or call
1-800-887-2887 to find out about the training courses nearest you.
●Always follow the age recommendation:
- A child under 16 years old should never operate an ATV with engine size greater than 90cc.
●Never allow a child under age 16 to operate an ATV without adult supervision, and never allow
continued use of an ATV by a child if he or she does not have the abilities to operate it safely.
●Never carry passenger on an ATV.
●Always avoid operating an ATV on any paved surfaces, including sidewalks, driveways, park-
ing lots and streets.
●Never operate an ATV on any public street, road or highway, even a dirt or gravel one.
U5KM12.book Page 1 Wednesday, March 26, 2003 3:50 PM

2-2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
●Never operate an ATV without wearing an approved motorcycle helmet that fits properly. You
should also wear eye protection (goggles or face shield), gloves, boots, long-sleeved shirt or
jacket, and long pants.
●Never consume alcohol or drugs before or while operating this ATV.
●Never operate at speeds too fast for your skills or the conditions. Always go at a speed that is
proper for the terrain, visibility and operating conditions, and your experience.
●Never attempt wheelies, jumps, or other stunts.
●Always inspect your ATV each time you use it to make sure it is in safe operating condition. Al-
ways follow the inspection and maintenance procedures and schedules described in this man-
ual.
●Always keep both hands on the handlebars and both feet on the footboards of the ATV during
operation.
●Always go slowly and be extra careful when operating on unfamiliar terrain. Always be alert to
changing terrain conditions when operating the ATV.
●Never operate on excessively rough, slippery or loose terrain until you have learned and prac-
ticed the skills necessary to control the ATV on such terrain. Always be especially cautious on
these kinds of terrain.
●Always follow proper procedures for turning as described in this manual. Practice turning at low
speeds before attempting to turn at faster speeds. Do not turn at excessive speed.
●Never operate the ATV on hills too steep for the ATV or for your abilities. Practice on smaller
hills before attempting larger hills.
U5KM12.book Page 2 Wednesday, March 26, 2003 3:50 PM

2-3
●Always follow proper procedures for climbing hills as described in this manual. Check the ter-
rain carefully before you start up any hill. Never climb hills with excessively slippery or loose
surfaces. Shift your weight forward. Never open the throttle suddenly. Never go over the top of
a hill at high speed.
●Always follow proper procedures for going down hills and for braking on hills as described in
this manual. Check the terrain carefully before you start down any hill. Shift your weight back-
ward. Never go down a hill at high speed. Avoid going down a hill at an angle that would cause
the vehicle to lean sharply to one side. Go straight down the hill where possible.
●Always follow proper procedures for crossing the side of a hill as described in this manual.
Avoid hills with excessively slippery or loose surfaces. Shift your weight to the uphill side of the
ATV. Never attempt to turn the ATV around on any hill until you have mastered the turning
technique described in this manual on level ground. Avoid crossing the side of a steep hill if
possible.
●Always use proper procedures if you stall or roll backwards when climbing a hill. To avoid stall-
ing, use proper gear range and maintain a steady speed when climbing a hill. If you stall or roll
backwards, follow the special procedure for braking described in this manual. Dismount on the
uphill side or to a side if pointed straight uphill. Turn the ATV around and remount, following the
procedure described in this manual.
U5KM12.book Page 3 Wednesday, March 26, 2003 3:50 PM

2-4
●Always check for obstacles before operating in a new area. Never attempt to operate over
large obstacles, such as large rocks or fallen trees. Always follow proper procedures when op-
erating over obstacles as described in this manual.
●Always be careful when skidding or sliding. Learn to safely control skidding or sliding by prac-
ticing at low speeds and on level, smooth terrain. On extremely slippery surfaces, such as ice,
go slowly and be very cautious in order to reduce the chance of skidding or sliding out of con-
trol.
●Never operate an ATV in fast flowing water or in water deeper than that recommended in this
manual. Remember that wet brakes may have reduced stopping ability. Test your brakes after
leaving water. If necessary, apply them several times to let friction dry out the linings.
●Always be sure there are no obstacles or people behind you when you operate in reverse.
When it is safe to proceed in reverse, go slowly.
●Always use the size and type tires specified in this manual.
●Always maintain proper tire pressure as described in this manual.
●Never modify an ATV through improper installation or use of accessories.
●Never exceed the stated load capacity for an ATV. Cargo should be properly distributed and
securely attached. Reduce speed and follow instructions in this manual for carrying cargo or
pulling a trailer. Allow greater distance for braking.
FOR MORE INFORMATION ABOUT ATV SAFETY, call the Consumer Products Safety Com-
mission at 1-800-638-2772, or the ATV Distributor’s Safety Hotline at 1-800-852-5344.
U5KM12.book Page 4 Wednesday, March 26, 2003 3:50 PM

2-5
WARNING
POTENTIAL HAZARD
Improper handling of gasoline.
WHAT CAN HAPPEN
Gasoline can catch fire and you could
be burned.
HOW TO AVOID THE HAZARD
Always turn off the engine when refuel-
ing. Do not refuel right after the engine
has been running and is still very hot.
Do not spill gasoline on the engine or
exhaust pipe/muffler when refueling.
Never refuel while smoking, or while in
the vicinity of sparks, open flames, or
other sources of ignition such as the pi-
lot lights of water heaters and clothes
dryers.
When transporting the ATV in another
vehicle, be sure it is kept upright and
that the fuel cock is in the “OFF”posi-
tion. Otherwise, fuel may leak out of the
carburetor or fuel tank.
WHAT CAN HAPPEN
Gasoline is poisonous and can cause
injuries.
HOW TO AVOID THE HAZARD
If you should swallow some gasoline or
inhale a lot of gasoline vapor, or get
some gasoline in your eyes, see your
doctor immediately. If gasoline spills on
your skin, wash with soap and water. If
gasoline spills on your clothing, change
your clothes.
U5KM12.book Page 5 Wednesday, March 26, 2003 3:50 PM

2-6
WARNING
POTENTIAL HAZARD
Starting or running the engine in a
closed area.
WHAT CAN HAPPEN
Exhaust fumes are poisonous and may
cause loss of consciousness and death
within a short time.
HOW TO AVOID THE HAZARD
Always operate your ATV in an area with
adequate ventilation.
U5KM12.book Page 6 Wednesday, March 26, 2003 3:50 PM

3-1
EBU00032
DESCRIPTION AND MACHINE IDENTIFICATION
1. Rear shock absorber spring
preload adjusting ring
2. Storage compartment and tool kit
3. Air filter case
4. Front brake fluid reservoir
5. Front shock absorber spring
preload adjusting ring
6. Rear brake fluid reservoir
7. Rear brake pedal
8. V-belt case drain plug
9. Radiator cap
10. Drive select lever
11. Fuel tank cap
12. Fuel cock
13. Fuses
14. Battery
15. Engine oil dipstick
16. Recoil starter
17. Coolant reservoir
18. Drive select lever box check hose
19. V-belt cooling duct check hose
20. Rear brake lever
21. Left handlebar switches
22. Starter (choke)
23. Speedometer unit
24. Main switch
25. Right handlebar switches
26. Throttle lever
27. Front brake lever
28. Auxiliary DC jack
N
O
TE:
The machine you have purchased may differ slightly
from those shown in the figures of this manual.
U5KM12.book Page 1 Wednesday, March 26, 2003 3:50 PM