Yamaha DT501988 User manual

~YAMAHA
f). sr "'
OWNER'S MANUAL
38 K-28199- 71

A-604 IDENTIFICATION
NUMBERS RECORD
1. KEY NUMBER:
2. VEHICLE NUMBER:
3. ENGINE NUMBER:
Your key identification number is stamped
on your key
as shown in the following illus-
tration.
Record this number
in the space provided for
reference if you need a new key.
Key number
Record your vehicle and engine numbers in
the spaces provided
to assist you in ordering
spare parts from your Yamaha dealer or for
reference in case your vehicle
is stolen. (See
page
3-1)

DT50W
OWNER'S MANUAL
©1988 by Yamaha Motor Co., Ltd.
1st Edition, June 1988
All rights reserved. Any reprinting or
unauthorized use without the written
permission of yamaha Motor Co., Ltd.
is expressly
prohibited.
Printed in Japan

A-200
INTRODUCTION
Congratulations on your purchase of the
Yamaha DT50W. This model
is the result of
Yamaha's vast experience in the production
of fine sporting, touring, and pacesetting
racing machines.
It representsthe highdegree
of craftsmanship and reliability that have
made Yamaha a leader
in these fields.
This manual will give you an understanding
of the operation, inspection, and basic
maintenance
of this motorcycle. If you have
any questions
about the operation or main-
tenance
of your motorcycle, please consult
a Yamaha dealer.
U-001
NOTE:~~~~~~~~~~~~
Some data in this manual may become out-
dated due to future improvement on this
model. If you have any questions about this
manual or your motorcycle, please consult a
Yamaha dealer.
TECHNICAL PUBLICATIONS
SERVICE DIVISION
MOTORCYCLE GROUP.
YAMAHA MOTOR CO .. LTD.

A-101
U-601
&WARNING:
PLEASE READ THIS MANUAL CARE-
FULLY AND COMPLETELY BEFORE
OPERATING THIS MOTORCYCLE.
Particularly important information is distin-
guished
in this manual by the following no-
tations:
NOTE:
A NOTE provides key information to make
procedures easier or clearer.
A CAUTION indicatesspecial proceduresthat
must
be followed to avoid damage to the
motorcycle.
&WARNING:
A WARNING indicates special procedures
that must be followed to avoid injury
to a
motorcycle operator or person inspecting or
repairing the motorcycle.
U-000
NOTE:~~~~~~~~~~~~
This manual should be considered a perma-
nent part of this motorcycle and should re-
main
with it even if the motorcycle is subse-
quently sold.

U-754
LI':, TIPS FOR SAFETY
TWO-WHEELED MOTORCYCLES ARE SINGLE TRACK VEHICLES. THEIR SAFE
USE AND OPERATION ARE DEPENDENT UPON THE USE OF PROPER RIDING
TECHNIQUES AS WELL AS THE EXPERTISE OF THE OPERATOR.
EVERY OPERATOR SHOULD KNOW THE FOLLOWING REQUIREMENTS BE-
FORE RIDING.
HE OR SHE SHOULD:
1. OBTAIN THOROUGH INSTRUCTIONS FROM A COMPETENT SOURCE ON
ALL ASPECTS OF MOTORCYCLE OPERATION.
2. OBSERVE THE WARNINGS AND MAINTENANCE REQUIREMENTS IN THE
OWNER'S MANUAL.
3. OBTAIN QUALIFIED TRAINING IN SAFE AND PROPER RIDING TECHNIQUES.
4. OBTAIN PROFESSIONAL TECHNICAL SERVICE AS INDICATED BY THE
OWNER'S MANUAL AND/OR WHEN MADE NECESSARY BY MECHANICAL
CONDITIONS.

, ______ ---
SAFE RIDING
1. Always make pre-operation checks. Careful checks may help prevent an ac-
cident.
2. This motorcycle is designed to carry the operator only No passengers.
3. The failure of motorists to detect and recognize motorcycles in traffic is the
predominating cause of automobile/motorcycle accidents. Many accidents
have been caused by an automobile driver who did not see the mtorcycle.
Making yourself conspicuous appears to be very effective in reducing the
chance of this type of accident.
Therefore:
a. Wear a brightly colored jacket.
b. Use extra caution when you approach and pass through intersections,
since intersections are the most likely places for motorcycle accidents.
c. Ride where other motorists can see you. Avoid riding in another motorist's
"blind spot."
4. Many accidents involve inexperienced operators. In fact, many operators
who have been involved in accidents do not even have a current motorcycle
license.
a. Make sure you are qualified. Also, only lend your motorcycle to experi-
enced operators.

b. Know your skills and limits. Staying within your limits may help you to
avoid an accident.
c. We recommend that you practice riding your motorcycle where there is
no traffic until you have become thoroughly familiar with your motorcycle
and all of its controls.
5. Many motorcycle accidents have been caused by motorcycle operator errors.
A typical error made by the operator is veering wide on a turn due to EX-
CESSIVE SPEED or undercornering (insufficient lean angle for the speed).
a. Always obey the speed limits and never travel faster than warranted by
road and traffic conditions.
b. Always signal before turning or changing lanes. Make sure other motorists
see you.
6. Operator's posture is important for proper control.
The operator should keep both hands on the handlebars and both feet on the
operator footrests during operation to maintian control of the motorcycle.
7. Never ride under the influence of alcohol or drugs.
PROTECTIVE APPAREL
The majority of fatalities from motorcycle accidents are the result of head in-
juries. The use of a safety helmet is the single most critical factor in the pre-
vention or reduction of head injuries.

- --- ------- ------- ---
1. Always wear an approved helmet.
2. Wear a face shield or goggles. Wind on your unprotected eyes could con-
tribute to an impairment of vision which could delay seeing a hazard.
3. The use of heavy boots, jacket, trousers, gloves, etc. is effective in preventing
or reducing abrations or lacerations.
4. Never wear loose fitting clothing. It could catch on the control levers,
footrests, or wheels and cause injury or accident.
5. Never touch the engine or exhaust system during or after operation. They
become very hot and can cause burns. Always wear protective clothings that
covers your legs, ankles, and feet.
MODIFICATION
Modifications made to the motorcycle not approved by Yamaha, or the removal
of original equipment, may render your motorcycle unsafe for use and may cause
severe personal injury. Modifications may also make your motorcycle illegal to
use.

LOADING AND ACCESSORIES
Adding accessories or cargo to your motorcycle can adversely affect stability
and handling if the weight distribution of the machine is changed. To avoid the
possibility of an accident, extreme caution should be used if adding cargo or
accessories to your motorcycle. Use extra care if riding a motorcycle which has
added cargo or accessories. Here are some general guidelines to follow if loading
cargo or adding accessories to your motorcycle:
LOADING
The total weight of the operator, accessories and cargo must not exceed
the maximum load limit of 157 lbs. (71 kg).
When loading within these weight limits, keep the following in mind:
1. Cargo and accessory weight should be kept as low and close to the motorcycle
as possible. Be sure to distribute the weight as evenly as possible on both
sides of the machine to minimize imbalance or instability.
2. Shifting weights can create a sudden imbalance. Make sure that accessories
and cargo are securely attached to the motorcycle before riding. Recheck
accessory mounts and cargo restraints frequently.

3. Never attach any large or heavy items to the handlebars, front forks, or front
fender. These items, including such cargo as sleeping bags, duffle bags, or
tents, can create unstable handling or slow steering response.
ACCESSORIES
Genuine Yamaha accessories have been specifically designed for use on this
motorcycle. Since Yamaha cannot test all other accessories which may be
available, you must personally be responsible for the proper selection, instal-
lation and use of non-Yamaha accessories. You should use extreme caution when
selecting and installing any accessories.
Keep in mind these guidelines for mounting accessories in addition to those
provided under "LOADING''.
1. Never install accessories or carry cargo that would impair the performance
of your motorcycle. Carefully inspect the accessory before using it to make
sure it does not in any way reduce ground clearance or cornering clearance,
limit suspension travel, steering travel or control operation, or obscure lights
or reflectors.

a. Accessories fitted to the handlebar or the front fork area can create in-
stability due to improper weight distribution or aerodynamic changes. If
accessories are added to the handlebar or front fork area, they must be
as light weight as possible and should be kept to a minimum.
b. Bulky or large accessories may seriously affect the stability of the mo-
torcycle due to aerodynamic effects. Wind may attempt to lift the mo-
torcycle, or the motorcycle may become unstable in cross winds. These
accessories may also cause instability when being passed by or passing
large vehicle.
c. Certain accessories can displace the operator from his or her normal riding
position. This improper position limits the freedom of movement of the
operator and may limit control ability. Therefore such accessories are
not recommended.
2. Caution must be used if adding electrical accessories. If these accessories
exceed the capacity of motorcycle's electrical system, an electric failure could
result, which could cause a dangerous loss of lights or engine power.

GASOLINE AND EXHAUST GAS
1. GASOLINE IS HIGHLY FLAMMABLE:
a. Always turn off the engine when refueling.
b. Take care not to spill any gasoline on the engine or exhaust
pipe(s)/muffler(s) when refueling.
c. Never refuel while smoking or in the vicinity of an open flame.
2. Never start the engine or let it run for any length of time in a closed area.
The exhaust fumes are poisonous and may cause loss of consciousness and
death within a short time. Always operate your motorycle in an area that
has adequate ventilation.
3. Always turn off the engine before leaving the motorcycle unattended and
remove the ignition key. When parking the motorcycle, note the following:
a. The engine and exhaust pipe(s)/muffler(s) may be hot. Park the motorcycle
in a place where pedestrians or children are not likely to touch these hot
areas.
b.
Do not park the motorcycle on a slope or soft ground: the motorcycle
may fall over.
c. Do not park the motorcycle near an flammable source, e.g. a kerosene
heater, or near an open flame. The motorcycle could catch fire.

4. When transporting the motorcycle in another vehicle, be sure it is kept upright
and that the fuel cock(s) is turned to "ON" or "RES" (for vacuum type)/"OFF"
(for manual type). If it should lean over, gasoline may leak out of the car-
buretor or fuel tank.
5. If you should swallow any gasoline, inhale a lot of gasoline vapor, or allow
gasoline to get in your eye(s), see your doctor immediately. If any gasoline
spills on your skin or clothing, immediately wash with soap and water and
change your clothes.

A-305 CONTENTS
LOCATION OF THE
Rear brake pedal................................. 4- 7
IMPORTANT LABELS .......................... 1 -1 Fuel cock ............................................ 4- 7
Starter knob (CHOKE) .......................
4-8
DESCRIPTION....................................... 2-1 Kick starter .......................................... 4-8
Steering lock....................................... 4-9
MOTORCYCLE IDENTIFICATION ....... 3-1 Helmet holder ..................................... 4-9
Vehicle identification number............. 3-1 Note handling of the Yamaha
Engine serial number.......................... 3-1 Energy Induction system .................. 4-10
Sidestand .......................................... 4-11
CONTROL FUNCTIONS ....................... 4-1 Sidestand switch operation check
... 4-11
Main switch
.. ................ .. .................... 4-1
Indicator lights....................................
4-2
PRE-OPERATION CHECKS.................. 5-1
Oil warning light checking method.... 4-3
Brakes ................................................. 5-3
Speedometer....................................... 4-4
Clutch ................................................. 5-3
Tachometer ......................................... 4-4
Throttle grip ........................................ 5-3
Engine temperature gauge ................. 4-4
Engine oil ............................................ 5-3
Handlebar switches ............................ 4-5
Transmission oil .................................. 5-4
Clutch lever......................................... 4-6
Coolant ............................................... 5-5
Change pedal...................................... 4-6
Chain................................................... 5-6
Front brake lever ................................. 4- 7 Tires ....................................................
5-6

Wheels ................................................ 5-8 Transmission oil replacement ............. 7-7
Fittings/Fasteners ...............................
5-9 Cooling system................................. 7-8
Lights and signals............................... 5-9 Fuel cock cleaning............................ 7-11
Switches
.. .. .. . .. ...... .... ... .. . .. .. ... .. . .. ... .. ... 5-9 Air filter ............................................. 7-11
Battery.................................................
5-9
Carburetor adjustment...................... 7-13
Fuel ..................................................... 5-9
Idle speed adjustment....................... 7-13
Throttle cable adjustment................. 7-14
OPERATION AND IMPORTANT Spark plug inspection....................... 7-15
RIDING POINTS ................................... 6-1 Front brake adjustment..................... 7-16
Starting a cold engine ........................ 6-1 Rear brake adjustment...................... 7-17
Engine warm-up ................................. 6-3
Brake light switch adjustment.......... 7-18
Starting a warm engine ...................... 6-3
Checking the brake shoes ................ 7-19
Shifting ............................................... 6-3
Clutch adjustment ............................ 7-19
Engine break-in ..................................
6-4
Mechanism adjustment .................... 7-20
Parking................................................ 6-5 Drive chain slack check .................... 7-20
Drive chain slack adjustment............ 7-21
PERIODIC MAINTENANCE AND Drive chain lubrication ..................... 7-22
MINOR REPAIR .................................... 7-1 Cable inspection and lubrication......
7-23
Tool kit ................................................ 7-1 Throttle cable and grip lubrication
... 7-23
Periodic maintenance/lubrication ...... 7-3 Autolube pump adjustment.............. 7 24
Torque specifications..........................
7-5
Brake and change pedals ................. 7-24
Transmission oil level check ............... 7-6 Brake and clutch levers .................... 7-24

Sidestand .......................................... 7-24 CLEANING AND STORAGE................. 8-1
Front fork inspection ........................
7-24 A. Cleaning ......................................... 8-1
Rear shock (Monocross suspension
B. Storage ........................................... 8-2
"De Carbon" system ......................... 7-26
Steering inspection...........................
7-26 SPECIFICATIONS ................................. 9-1
Wheel bearings................................. 7-27
Battery............................................... 7-27 WIRING DIAGRAM
Replenishing the battery fluid .......... 7-28
Fuse replacement.............................. 7-29
Replacing the headlight bulb ........... 7-30
Headlight beam adjustment ............. 7-30
Replacing the taillight
and flasher light bulb........................ 7-31
Front wheel removal......................... 7-31
Front wheel installation ....................
7-32
Rear wheel removal .......................... 7-33
Rear wheel installation .. ........ ... .. ...... 7-34
Troubleshooting ............................... 7-35
Troubleshooting chart ...................... 7-36

A-400 LOCATION
OF THE IMPORTANT LABELS
Please read following labels carefully before operating this motorcycle.
2 3 4
1·1

(j)("_M_F_D-.-,-Y~Y-A_M_A_H~A-M~O-T_O_R_C_D-.-.-,-T-D-.:::::::::=A:::::::::;--:-(5:0:6-1~~~~ .....
®
GVWR •••• kg GAWR FRONT • •••• kg, WITH •••• (B) TIRE,
•••••RIM. AT •on PSI COLD. REAR - **"• Kg. WITH
••••• (B) TIRE, •••• AIM, AT •••• PSI COLD.
THIS VEHICLE CONFORMS TO ALL APPLICABLE FEDERAL MOTORVEHICLE
SAFETY STANDARDS IN EFFECT ON THE DATE OF MANUFACTURE
SHOWN ABOVE.
VEHICLE ID NO. 8
TYPE CLASSIFICATION··· MOTORCYCLE.
HOW TO LAYOUT
IBATTERYI BREATHER
PIPE
21A-00
CAUTION
!BATTERY REMOVAL ANO INSTALLATION!
1.Bc careful 001 10 SPiash tho electrolyte to
the drive chain,
2.Remove the breather pipe before
demountrng the baucry,
3.After insrnlling the battery, be sure 10
connect the breather pipe into place.
1-2
I WARNING I
OPERATOR ONLY
NO PASSENGERS
I AVERTISSEMENTI
OPERATEUR UNIOUEMENT
PAS DE PASSAGERS

A-500
14 15
j I i
, ; I
\~
DESCRIPTION
2-1
1. Tail/Brake light 12. Silencer
2. Rear flasher light 13. Change pedal
3. Monocross suspension 14. Clutch lever
4. Kick starter 15. Handlebar switch
5.
Front fender 16. Speedometer
6. Brake pedal 17. Main switch
7.
Footrest 18. Tachometer
8. Front fork
19. Brake lever
9. Headlight
20. Throttle grip
10. Fuet tank
21. Front flasher light
11. Seat
22. Radiator
U-002
NOTE: ~~~~~~~~~~~~~
The motorcycle you have purchased may differ
slightly from those shown in the photographs.