Yamaha XG250 User manual

SERVICE MANUAL
XG250
4D6-28197-E0

NOTICE
This manual was produced by the Yamaha Motor Company, Ltd. primarily for use by Yamaha dealers
and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one man-
ual. Therefore, anyone who uses this book to perform maintenance and repairs on Yamaha vehicles
should have a basic understanding of mechanics and the techniques to repair these types of vehicles.
Repair and maintenance work attempted by anyone without this knowledge is likely to render the vehi-
cle unsafe and unfit for use.
This model has been designed and manufactured to perform within certain specifications in regard to
performance and emissions. Proper service with the correct tools is necessary to ensure that the vehi-
cle will operate as designed. If there is any question about a service procedure, it is imperative that you
contact a Yamaha dealer for any service information changes that apply to this model. This policy is
intended to provide the customer with the most satisfaction from his vehicle and to conform to federal
environmental quality objectives.
Yamaha Motor Company, Ltd. is continually striving to improve all of its models. Modifications and sig-
nificantchangesinspecificationsorprocedureswillbeforwardedtoallauthorizedYamahadealersand
will appear in future editions of this manual where applicable.
NOTE:
●
This Service Manual contains information regarding periodic maintenance to the emission control
system. Please read this material carefully.
●
Designs and specifications are subject to change without notice.
IMPORTANT MANUAL INFORMATION
Particularly important information is distinguished in this manual by the following.
The Safety Alert Symbol means ATTENTION! BECOME ALERT!YOUR SAFETY
IS INVOLVED!
Failure to follow WARNING instructions could result in severe injury or death to
the vehicle operator, a bystander or a person checking or repairing the vehicle.
A CAUTION indicates special precautions that must be taken to avoid damage to
the vehicle.
A NOTE provides key information to make procedures easier or clearer.
WARNING
CAUTION:
NOTE:

HOW TO USE THIS MANUAL
This manual is intended as a handy, easy-to-read reference book for the mechanic. Comprehensive
explanations of all installation, removal, disassembly, assembly, repair and check procedures are laid
out with the individual steps in sequential order.
●
The manual is divided into chapters and each chapter is divided into sections. The current section
title is shown at the top of each page “1”.
●
Sub-section titles appear in smaller print than the section title “2”.
● To help identify parts and clarify procedure steps, there are exploded diagrams at the start of each
removal and disassembly section “3”.
●
Numbers are given in the order of the jobs in the exploded diagram. A number indicates a disassem-
bly step “4”.
●
Symbols indicate parts to be lubricated or replaced “5”.
Refer to “SYMBOLS”.
●
A job instruction chart accompanies the exploded diagram, providing the order of jobs, names of
parts, notes in jobs, etc “6”.
●
Jobsrequiringmore information (such as special tools and technical data) are described sequentially
“7”.
3
4
5
6
7
CLUTCH
5-29
Removing the clutch
Order Job/Parts to remove Q ty Remarks
1 Clutch spring 5
2 Pressure plate 1
3Primary drive gear nut 1
4Friction plate 6
5 Clutch plate 5
6 Cushion spring 1
7 Seat plate 1
8 Clutch boss nut 1
9 Clutch boss 1
10 Thrust washer 1
11 Clutch housing 1
12 Claw washer 1
13 Primary driven gear 1
14 Locknut/Washer 1/1
15 Push rod1 1
16 Push plate 1
17 Push rod 2/Ball 1/1
3
12
45
678
9
10
11
12 13
14
16 15
17
CLUTCH
5-32
2. Straighten the lock washer tab.
3. Loosen:
Primary drive gear nut
Clutch boss nut
NOTE:
Place the aluminum plate a between clutch
housing 1 and primary drive gear 2 , and
then loosen the primary drive gear nut 3 .
While holding the clutch boss 4 with the uni-
versal clutch holder, loosen the clutch boss
nut 5 .
4. Remove:
Clutch boss nut 1
Lock washer 2
Clutch boss 3
Thrust washer 4
Clutch housing 5
5. Remove:
Primary drive gear nut 1
Lock washer 2
Claw washer 3
Primary drive gear 4
EAS25100
CHECKING THE FRICTION PLATES
The following procedure applies to all of the fric-
tion plates.
1. Check:
Friction plate
Damage/wear Replace the friction plates
as a set.
2. Measure:
Friction plate thickness
Out of specification Replace the friction
plates as a set.
NOTE:
Measure the friction plate at four places.
Universal clutch holder
90890-04086
YM-91042
1
2
1
2
3
a
4
5
Friction plate thickness
2.90—3.10 mm (0.11—0.12 in)
Wear limit
2.80 mm (0.1102 in)
1
2
3
4
5
1
2
3
4
2
1

SYMBOLS
The following symbols are used in this manual
for easier understanding.
NOTE:
The following symbols are not relevant to every
vehicle.
GM
E
BLS M
91011
12 13 14
15 16
LT New
T
R
.
.
123
456
78
1. Serviceable with engine mounted
2. Filling fluid
3. Lubricant
4. Special tool
5. Tightening torque
6. Wear limit, clearance
7. Engine speed
8. Electrical data
9. Engine oil
10. Gear oil
11. Molybdenum-disulfide oil
12. Wheel-bearing grease
13. Lithium-soap-based grease
14. Molybdenum-disulfide grease
15. Apply locking agent (LOCTITE®)
16. Replace the part

GENERAL INFORMATION
1
SPECIFICATIONS
2
PERIODIC CHECKS AND
ADJUSTMENTS
3
CHASSIS
4
ENGINE
5
FUEL SYSTEM
6
ELECTRICAL SYSTEM
7
TROUBLESHOOTING
8
EAS20110
TABLE OF CONTENTS

1
2
3
4
5
6
7
8
9
GENERAL INFORMATION
IDENTIFICATION ........................................................................................1-1
VEHICLE IDENTIFICATION NUMBER...................................................1-1
MODEL LABEL .......................................................................................1-1
ENGINE SERIAL NUMBER....................................................................1-1
IMPORTANT INFORMATION .....................................................................1-2
PREPARATION FOR REMOVAL AND DISASSEMBLY ........................1-2
REPLACEMENT PARTS ........................................................................1-2
GASKETS, OIL SEALS AND O-RINGS..................................................1-2
LOCK WASHERS/PLATES AND COTTER PINS...................................1-2
BEARINGS AND OIL SEALS..................................................................1-2
CIRCLIPS................................................................................................1-3
CHECKING THE CONNECTIONS..............................................................1-4
SPECIAL TOOLS........................................................................................1-5

IDENTIFICATION
1-1
IDENTIFICATION
VEHICLE IDENTIFICATION NUMBER
The vehicle identification number “1” is stamped
into the right side of the steering head pipe.
MODEL LABEL
The model label “1” is affixed to the frame. This
information will be needed to order spare parts.
ENGINE SERIAL NUMBER
The engine serial number “1” is stamped into the
elevated part of the right rear section of the en-
gine.
1
1
1

IMPORTANT INFORMATION
1-2
IMPORTANT INFORMATION
PREPARATION FOR REMOVAL AND
DISASSEMBLY
1. Before removal and disassembly, remove all
dirt, mud, dust and foreign material.
2. Use only the proper tools and cleaning
equipment.
Refer to “SPECIAL TOOLS” on page 1-5.
3. When disassembling, always keep mated
parts together. This includes gears, cylin-
ders, pistons and other parts that have been
“mated” through normal wear. Mated parts
must always be reused or replaced as an as-
sembly.
4. During disassembly, clean all of the parts
and place them in trays in the order of disas-
sembly. This will speed up assembly and al-
low for the correct installation of all parts.
5. Keep all parts away from any source of fire.
REPLACEMENT PARTS
Use only genuine Yamaha parts for all replace-
ments. Use oil and grease recommended by
Yamaha for all lubrication jobs. Other brands
may be similar in function and appearance, but
inferior in quality.
GASKETS, OIL SEALS AND O-RINGS
1. When overhauling the engine, replace all
gaskets, seals and O-rings. All gasket sur-
faces, oil seal lips and O-rings must be
cleaned.
2. During reassembly, properly oil all mating
parts and bearings and lubricate the oil seal
lips with grease.
LOCK WASHERS/PLATES AND COTTER
PINS
After removal, replace all lock washers/plates
“1” and cotter pins. After the bolt or nut has been
tightened to specification, bend the lock tabs
along a flat of the bolt or nut.
BEARINGS AND OIL SEALS
Install bearings and oil seals so that the manu-
facturer’s marks or numbers are visible. When
installing oil seals “1”, lubricate the oil seal lips
with a light coat of lithium-soap-based grease.
Oil bearings liberally when installing, if appropri-
ate.

IMPORTANT INFORMATION
1-3
CAUTION:
Do not spin the bearing with compressed air
because this will damage the bearing surfac-
es.
CIRCLIPS
Before reassembly, check all circlips carefully
and replace damaged or distorted circlips. Al-
ways replace piston pin clips after one use.
When installing a circlip “1”, make sure the
sharp-edged corner “2” is positioned opposite
the thrust “3” that the circlip receives.

CHECKING THE CONNECTIONS
1-4
CHECKING THE CONNECTIONS
Check the leads, couplers, and connectors for
stains, rust, moisture, etc.
1. Disconnect:
●
Lead
●
Coupler
●
Connector
2. Check:
●
Lead
●
Coupler
●
Connector
Moisture → Dry with an air blower.
Rust/stains → Connect and disconnect sev-
eral times.
3. Check:
● All connections
Loose connection → Connect properly.
NOTE:
If the pin “1” on the terminal is flattened, bend it
up.
4. Connect:
● Lead
●
Coupler
●
Connector
NOTE:
Make sure all connections are tight.
5. Check:
●
Continuity
(with the pocket tester)
NOTE:
●
If there is no continuity, clean the terminals.
●
When checking the wire harness, perform
steps (1) to (3).
●
As a quick remedy, use a contact revitalizer
available at most part stores.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C

SPECIAL TOOLS
1-5
SPECIAL TOOLS
The following special tools are necessary for complete and accurate tune-up and assembly. Use only
the appropriate special tools as this will help prevent damage caused by the use of inappropriate tools
or improvised techniques. Special tools, part numbers or both may differ depending on the country.
When placing an order, refer to the list provided below to avoid any mistakes.
NOTE:
For U.S.A. and Canada, use part number starting with “YM-”, “YU-”, or “ACC-”.
For others, use part number starting with “90890-”.
Tool name/Tool No. Illustration Reference
pages
Slide hammer bolt
90890-01083
Slide hammer bolt 6 mm
YU-01083-1
5-13
Weight
90890-01084
YU-01083-3
5-13
Crankcase separating tool
90890-01135
Crankcase separator
YU-01135-B
5-59
Valve spring compressor attachment
90890-01243
Valve spring compressor adapter (26 mm)
YM-01253-1
5-18, 5-23
YU-01083-3

SPECIAL TOOLS
1-6
Valve spring compressor
90890-04019
YM-04019
5-18, 5-23
Ring nut wrench
90890-01268
Spanner wrench
YU-01268
4-50
Crankshaft installer pot
90890-01274
Installing pot
YU-90058
5-61
Crankshaft installer bolt
90890-01275
Bolt
YU-90060
5-61
Spacer
90890-01288 5-61
Adapter (M10)
90890-01383
Adapter #2
YU-90062
5-61
Tool name/Tool No. Illustration Reference
pages
YU-90058/YU-90059

SPECIAL TOOLS
1-7
Damper rod holder
90890-01294
Damping rod holder set
YM-01300
4-43, 4-45
T-handle
90890-01326
T-handle 3/8" drive 60 cm long
YM-01326
4-43, 4-45
Tappet adjusting tool
90890-01311
Valve adjuster 3 mm & 4 mm
YM-08035-A
3-4
Flywheel puller
90890-01362
Heavy duty puller
YU-33270-B
5-51
Fork seal driver weight
90890-01367
Replacement hammer
YM-A9409-7
4-45, 4-46
Fork seal driver attachment ( ø 35)
90890-01369
Replacement 35 mm
YM-A9409-5
4-45, 4-46
Tool name/Tool No. Illustration Reference
pages
YM-01300
YM-A9409-7/YM-A5142-4

SPECIAL TOOLS
1-8
Steering nut wrench
90890-01403
Spanner wrench
YU-33975
3-20
Sheave holder
90890-01701
Primary clutch holder
YS-01880-A
5-51, 5-52
Thickness gauge
90890-03079
Narrow gauge set
YM-34483
3-4
Compression gauge
90890-03081
Engine compression tester
YU-33223
3-9
Extension
90890-04082 3-9
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
1-4, 7-35, 7-36,
7-37, 7-41,
7-42, 7-43,
7-44, 7-45, 7-47
Pocket tester
90890-03132 3-4
Digital circuit tester
90890-03174
Model 88 Multimeter with tachometer
YU-A1927
5-47
Valve guide remover ( ø 6)
90890-04064
Valve guide remover (6.0 mm)
YM-04064-A
5-20
Tool name/Tool No. Illustration Reference
pages

SPECIAL TOOLS
1-9
Valve guide installer ( ø 6)
90890-04065
Valve guide installer (6.0 mm)
YM-04065-A
5-20
Valve guide reamer ( ø 6)
90890-04066
Valve guide reamer (6.0 mm)
YM-04066
5-20
Universal clutch holder
90890-04086
YM-91042
5-33, 5-35
Valve lapper
90890-04101
Valve lapping tool
YM-A8998
5-21
Ignition checker
90890-06754
Opama pet-4000 spark checker
YM-34487
7-44
Digital tachometer
90890-06760 3-4
Tool name/Tool No. Illustration Reference
pages

1
2
3
4
5
6
7
8
9
SPECIFICATIONS
GENERAL SPECIFICATIONS ....................................................................2-1
ENGINE SPECIFICATIONS........................................................................2-2
CHASSIS SPECIFICATIONS......................................................................2-9
ELECTRICAL SPECIFICATIONS...............................................................2-12
TIGHTENING TORQUES............................................................................2-14
GENERAL TIGHTENING TORQUE SPECIFICATIONS.........................2-14
ENGINE TIGHTENING TORQUES.........................................................2-14
CHASSIS TIGHTENING TORQUES.......................................................2-16
LUBRICATION POINTS AND LUBRICANT TYPES ..................................2-19
ENGINE...................................................................................................2-19
CHASSIS.................................................................................................2-20
LUBRICATION SYSTEM CHART AND DIAGRAMS .................................2-21
ENGINE OIL LUBRICATION CHART.....................................................2-21
LUBRICATION DIAGRAMS....................................................................2-23
CABLE ROUTING.......................................................................................2-25

GENERAL SPECIFICATIONS
2-1
GENERAL SPECIFICATIONS
Model
Model 4D61
4D62
Dimensions
Overall length 2010 mm (79.1 in)
Overall width 800 mm (31.5 in)
Overall height 1145 mm (45.1 in)
Seat height 790 mm (31.1 in)
Wheelbase 1330 mm (52.4 in)
Ground clearance 280 mm (11.02 in)
Minimum turning radius 1900 mm (74.8 in)
Weight
With oil and fuel 120.0 kg (265 lb)
Maximum load 180 kg (397 lb)

ENGINE SPECIFICATIONS
2-2
ENGINE SPECIFICATIONS
Engine
Engine type Air cooled 4-stroke, SOHC
Displacement 249.0 cm
3
(15.19 cu.in)
Cylinder arrangement Forward-inclined single cylinder
Bore × stroke 74.0 × 58.0 mm (2.91 × 2.28 in)
Compression ratio 9.50 :1
Standard compression pressure (at sea level) 1200 kPa/300 r/min (170.7 psi/300 r/min)
(12.0 kgf/cm
2
/300 r/min)
Starting system Electric starter
Fuel
Recommended fuel Regular unleaded gasoline only
Fuel tank capacity 6.0 L (1.59 US gal) (1.32 Imp.gal)
Fuel reserve amount 1.9 L (0.50 US gal) (0.42 Imp.gal)
Engine oil
Lubrication system Wet sump
Type SAE10W30 or SAE10W40 or SAE15W40 or
SAE20W40 or SAE20W50
Recommended engine oil grade API service SE, SF, SG type or higher
Engine oil quantity
Total amount 1.40 L (1.48 US qt) (1.23 Imp.qt)
Without oil filter element replacement 1.20 L (1.27 US qt) (1.06 Imp.qt)
With oil filter element replacement 1.30 L (1.37 US qt) (1.14 Imp.qt)
Oil filter type Wire mesh
Oil pump
Oil pump type Trochoid
Inner-rotor-to-outer-rotor-tip clearance 0.150 mm (0.0059 in)
Limit 0.20 mm (0.0079 in)
Outer-rotor-to-oil-pump-housing clearance 0.010 – 0.034 mm (0.0004 – 0.0013 in)
Limit 0.050 mm (0.0020 in)
Oil-pump-housing-to-inner-and-outer-rotor clearance 0.04 – 0.09 mm (0.0016 – 0.0035 in)
Limit 0.15 mm (0.0059 in)
Pressure check location HEAD CYLINDER
Spark plug (s)
Manufacturer/model NGK/DR7EA
Spark plug gap 0.6 – 0.7 mm (0.024 – 0.028 in)
Cylinder head
Volume 20.50 – 21.50 cm
3
(1.25 – 1.31 cu.in)
Warpage limit 0.03 mm (0.0012 in)

ENGINE SPECIFICATIONS
2-3
Camshaft
Drive system Chain drive (right)
Camshaft journal diameter 24.960 – 24.980 mm (0.9827 – 0.9835 in)
Camshaft lobe dimensions
Intake A 36.520 – 36.620 mm (1.4378 – 1.4417 in)
Limit 36.460 mm (1.4354 in)
Intake B 30.201 – 30.301 mm (1.1890 – 1.1930 in)
Limit 30.151 mm (1.1870 in)
Exhaust A 36.564 – 36.664 mm (1.4395 – 1.4435 in)
Limit 36.514 mm (1.4376 in)
Exhaust B 30.216 – 30.316 mm (1.1896 – 1.1935 in)
Limit 30.166 mm (1.1876 in)
Camshaft runout limit 0.030 mm (0.0012 in)
Timing chain
Model/number of links DID SCR-0404 SDH/104
Tensioning system Automatic
Rocker arm/rocker arm shaft
Rocker arm inside diameter 12.000 – 12.018 mm (0.4724 – 0.4731 in)
Limit 12.036 mm (0.4739 in)
Rocker arm shaft outside diameter 11.981 – 11.991 mm (0.4717 – 0.4721 in)
Limit 11.950 mm (0.4705 in)
Rocker-arm-to-rocker-arm-shaft clearance 0.009 – 0.037 mm (0.0004 – 0.0015 in)
Valve, valve seat, valve guide
Valve clearance (cold)
Intake 0.05 – 0.10 mm (0.0020 – 0.0039 in)
Exhaust 0.10 – 0.15 mm (0.0039 – 0.0059 in)
Valve dimensions
Valve head diameter A (intake) 33.90 – 34.10 mm (1.3346 – 1.3425 in)
Valve head diameter A (exhaust) 28.40 – 28.60 mm (1.1181 – 1.1260 in)
Valve face width B (intake) 2.260 mm (0.0890 in)
Valve face width B (exhaust) 2.260 mm (0.0890 in)
A
B
A
B
A
B

ENGINE SPECIFICATIONS
2-4
Valve seat width C (intake) 0.90 – 1.10 mm (0.0354 – 0.0433 in)
Valve seat width C (exhaust) 0.90 – 1.10 mm (0.0354 – 0.0433 in)
Valve margin thickness D (intake) 0.80 – 1.20 mm (0.0315 – 0.0472 in)
Valve margin thickness D (exhaust) 0.80 – 1.20 mm (0.0315 – 0.0472 in)
Valve stem diameter (intake) 5.975 – 5.990 mm (0.2352 – 0.2358 in)
Limit 5.950 mm (0.2343 in)
Valve stem diameter (exhaust) 5.960 – 5.975 mm (0.2346 – 0.2352 in)
Limit 5.935 mm (0.2337 in)
Valve guide inside diameter (intake) 6.000 – 6.012 mm (0.2362 – 0.2367 in)
Limit 6.042 mm (0.2379 in)
Valve guide inside diameter (exhaust) 6.000 – 6.012 mm (0.2362 – 0.2367 in)
Limit 6.042 mm (0.2379 in)
Valve-stem-to-valve-guide clearance (intake) 0.010 – 0.037 mm (0.0004 – 0.0015 in)
Limit 0.080 mm (0.0032 in)
Valve-stem-to-valve-guide clearance (exhaust) 0.025 – 0.052 mm (0.0010 – 0.0020 in)
Limit 0.100 mm (0.0039 in)
Valve stem runout 0.030 mm (0.0012 in)
Cylinder head valve seat width (intake) 0.90 – 1.10 mm (0.0354 – 0.0433 in)
Limit 1.7 mm (0.07 in)
Cylinder head valve seat width (exhaust) 0.90 – 1.10 mm (0.0354 – 0.0433 in)
Limit 1.7 mm (0.07 in)
Valve spring
Inner spring
Free length (intake) 36.17 mm (1.42 in)
Limit 34.47 mm (1.36 in)
Free length (exhaust) 36.17 mm (1.42 in)
Limit 34.47 mm (1.36 in)
Installed length (intake) 30.50 mm (1.20 in)
Installed length (exhaust) 30.50 mm (1.20 in)
Spring rate K1 (intake) 14.70 N/mm (83.94 lb/in) (1.50 kgf/mm)
Spring rate K2 (intake) 19.00 N/mm (108.49 lb/in) (1.94 kgf/mm)
Spring rate K1 (exhaust) 14.70 N/mm (83.94 lb/in) (1.50 kgf/mm)
Spring rate K2 (exhaust) 19.00 N/mm (108.49 lb/in) (1.94 kgf/mm)
Installed compression spring force (intake) 75.00 – 91.70 N (16.86 – 20.61 lb) (7.65 – 9.35 kgf)
Installed compression spring force (exhaust) 75.00 – 91.70 N (16.86 – 20.61 lb) (7.65 – 9.35 kgf)
C
D