Yamaha 2002 YFM350X User manual

YFM350X(P)
SUPPLEMENTARY
SERVICE MANUAL
3GD-AE6
2002

FOREWORD
This Supplementary Service Manual has been prepared to introduce new service and new data for
the YFM350X(P) 2002. For complete information on service procedures, it is necessary to use this
Supplementary Service Manual together with the following manual.
YFM350X(J) ’97 SERVICE MANUAL: 3GD-AE5
YFM350X(P) 2002
SUPPLEMENTARY
SERVICE MANUAL
 2001 by Yamaha Motor Co., Ltd.
First Edition, May 2001
All rights reserved.
Any reproduction or unauthorized use
without the written permission of
Yamaha Motor Co., Ltd.
is expressly prohibited.

EB001000
NOTICE
This manual was produced by the Yamaha Motor Company primarily for use by Yamaha dealers
and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one
manual, so it is assumed that anyone who uses this book to perform maintenance and repairs on
Yamaha machine has a basic understanding of the mechanical ideas and the procedures of
machine repair. Repairs attempted by anyone without this knowledge are likely to render the
machine unsafe and unfit for use.
Yamaha Motor Company, Ltd. is continually striving to improve all its models. Modifications and sig-
nificant changes in specifications or procedures will be forwarded to all authorized Yamaha dealers
and will appear in future editions of this manual where applicable.
N
OTE:
Designs and specifications are subject to change without notice.
IMPORTANT INFORMATION
Particularly important information is distinguished in this manual by the following notations.
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 machine operator, a bystander or a person inspecting or repairing the
machine.
A CAUTION indicates special precautions that must be taken to avoid dam-
age to the machine.
A NOTE provides key information to make procedures easier or clearer.
WARNING
CAUTION:
N
O
TE:

HOW TO USE THIS MANUAL
CONSTRUCTION OF THIS MANUAL
This manual consists of chapters for the main categories of subjects. (See “Illustrated symbols”)
1st title 1: This is a chapter with its symbol on the upper right of each page.
2nd title 2: This title appears on the upper of each page on the left of the chapter sym-
bol. (For the chapter “Periodic inspection and adjustment” the 3rd title
appears.)
3rd title 3: This is a final title.
MANUAL FORMAT
All of the procedures in this manual are organized in a sequential, step-by-step format. The informa-
tion has been compiled to provide the mechanic with an easy to read, handy reference that contains
comprehensive explanations of all disassembly, repair, assembly, and inspections.
A set of particularly important procedure 4is placed between a line of asterisks “*” with each proce-
dure preceded by “●”.
IMPORTANT FEATURES
●Data and a special tool are framed in a box preceded by a relevant symbol 5.
●An encircled numeral 6indicates a part name, and an encircled alphabetical letter data or an
alignment mark 7, the others being indicated by an alphabetical letter in a box 8.
●A condition of a faulty component will precede an arrow symbol 9and the course of action will fol-
low it.
EXPLODED DIAGRAM
Each chapter provides exploded diagrams before each disassembly section for ease in identifying
correct disassembly and assembly procedures.

EB003000
ILLUSTRATED SYMBOLS
Illustrated symbols 1to 9are printed on the
top right of each page and indicate the subject
of each chapter.
1General information
2Specifications
3Periodic checks and adjustments
4Engine
5Carburetion
6Drive train
7Chassis
8Electrical
9Troubleshooting
Illustrated symbols 0to Fare used to identify
the specifications appearing in the text.
0Filling fluid
ALubricant
BSpecial tool
CTorque
DWear limit, clearance
EEngine speed
FΩ, V, A
Illustrated symbols Gto Min the exploded
diagrams indicate the types of lubricants and
lubrication points.
GApply engine oil
HApply gear oil
IApply molybdenum disulfide oil
JApply wheel bearing grease
KApply lightweight lithium soap base grease
LApply molybdenum disulfide grease
MApply silicon grease
Illustrated symbols Nto Oin the exploded
diagrams indicate where to apply a locking
agent Nand when to install a new part O.
NApply the locking agent (LOCTITE)
OReplace
12
34
56
78
90
AB
CD
EF
GHI
J
NO
GEN
INFO SPEC
CHK
ADJ ENG
CARB
DRIV
CHAS
–+
ELEC
TRBL
SHTG
T
R
.
.
EGM
BLS MS
KLM
LT New

CONTENTS
SPECIFICATIONS ............................................................................................1
GENERAL SPECIFICATIONS ..................................................................1
MAINTENANCE SPECIFICATIONS .........................................................2
ENGINE ................................................................................................2
CHASSIS ..............................................................................................4
ELECTRICAL ........................................................................................4
CABLE ROUTING .....................................................................................5
PERIODIC CHECKS AND ADJUSTMENTS ....................................................9
INTRODUCTION .......................................................................................9
PERIODIC MAINTENANCE/LUBRICATION INTERVALS ........................9
CHASSIS .................................................................................................11
ADJUSTING THE FRONT BRAKE......................................................11
ADJUSTING THE REAR BRAKE LIGHT SWITCH .............................11
CHASSIS ........................................................................................................12
FRONT SUSPENSION ...........................................................................12
ELECTRICAL .................................................................................................13
CHECKING THE SWITCH ......................................................................13
CHECKING THE SWITCH ..................................................................13
CHECKING A SWITCH SHOWN IN THE MANUAL ...........................13
IGNITION SYSTEM .................................................................................14
CIRCUIT DIAGRAM ............................................................................14
TROUBLESHOOTING ........................................................................15
SIGNAL SYSTEM ...................................................................................20
CIRCUIT DIAGRAM ............................................................................20
CHECKING THE SIGNAL SYSTEM ...................................................21
YFM350X(P) 2002 WIRING DIAGRAM

–1 –
SPEC
GENERAL SPECIFICATIONS
SPECIFICATIONS
GENERAL SPECIFICATIONS
Model YFM350X(P) 2002
Model code number: 5NF6 (CDN, Europe and Oceania)
Spark plug:
Type/manufacturer DR8EA (NGK)
Gap 0.6 ~ 0.7 mm (0.024 ~ 0.028 in)
Electrical:
Ignition system DC. C.D.I.
Charging system A.C. magneto
Battery capacity 12 V 12AH
Battery type GM12CZ-4A-2
Bulb wattage ×quantity:
Headlight 12 V 30 W/30 W ×2
Tail/brake light 12 V 5 W/21 W ×1
Neutral indicator light 12 V 3.4 W ×1
Reverse indicator light 12 V 3.4 W ×1

–2 –
SPEC
MAINTENANCE SPECIFICATIONS
MAINTENANCE SPECIFICATIONS
ENGINE
Model YFM350X(P) 2002
Cylinder:
Bore size 82.97 ~ 83.02 mm (3.267 ~ 3.269 in)
Taper limit <0.05 mm (0.002 in)>
Piston:
Piston size “D”82.92 ~ 82.97 mm (3.265 ~ 3.267 in)
Measuring point “H”5.5 mm (0.22 in)
(From bottom line of piston skirts)
Piston clearance 0.040 ~ 0.060 mm
(0.00157 ~ 0.00236 in)
Oversize 2nd 83.5 mm (3.287 in)
4th 84.0 mm (3.307 in)
Piston off-set 0.5 mm (0.02 in)
Piston off-set direction Intake side
Inside diameter (piston pin bore) 19.004 ~ 19.015 mm (0.7481 ~ 0.7486 in)
Outside diameter (piston pin) 18.991 ~ 19.000 mm (0.7477 ~ 0.7480 in)
Piston ring:
Sectional sketch
Top ring: Barrel
B 1.2 mm (0.047 in)
T 3.3 mm (0.130 in)
2nd ring: Tapper
B 1.5 mm (0.059 in)
T 3.4 mm (0.134 in)
Oil ring: B 2.8 mm (0.110 in)
T 2.8 mm (0.110 in)
End gap (installed)
Top ring 0.20 ~ 0.40 mm (0.00787 ~ 0.0157 in)
2nd ring 0.20 ~ 0.40 mm (0.00787 ~ 0.0157 in)
Oil ring 0.30 ~ 0.90 mm (0.012 ~ 0.035 in)
Side clearance Top ring 0.03 ~ 0.09 mm (0.0012 ~ 0.0035 in)
2nd ring 0.03 ~ 0.07 mm (0.0012 ~ 0.0028 in)
Clutch:
Friction plate thickness/quantity 2.74 ~ 2.86 mm (0.107 ~ 0.113 in)/6
Warp limit <2.64 mm (0.104 in)>
Friction plate thickness/quantity 2.94 ~ 3.06 mm (0.116 ~ 0.120 in)/1
Warp limit <2.84 mm (0.112 in)>
Clutch plate thickness/quantity 1.5 ~ 1.7 mm (0.059 ~ 0.066 in)/4
1.9 ~ 2.1 mm (0.0748 ~ 0.0827 in)/2
Max. warpage <0.2 mm (0.00787 in)>
Clutch spring free length/quantity 47.8 mm (1.882 in)/5
Clutch spring minimum free length 46.5 mm (1.831 in)
Clutch release method Outer push (rack and pinon)
H
D
B
T
B
T
B
T

–3 –
SPEC
MAINTENANCE SPECIFICATIONS
Carburetor:
I. D. mark 3GD 00
Main jet (M.J) #145
Main air jet (M.A.J) 0.6
Jet needle (J.N) 5J18-3
Needle jet (N.J) O-6
Pilot jet (P.J) #42.5
Pilot air jet (P.A.J.1) 1.0
(P.A.J.2) 0.7
Pilot outlet (P.O) 0.75
Bypass 1 (B.P.1) 0.8
Bypass 2 (B.P.2) 0.8
Bypass 3 (B.P.3) 0.8
Pilot screw (turns out) (P.S) 2
Valve seat (V.S) 2.5
Starter jet (G.S.) #62.5
Throttle valve size (Th.V) #125
Fuel level (F.L) 2 ~ 3 mm (0.08 ~ 0.12 in)
Float height 11.4 ~ 13.4 mm (0.45 ~ 0.53 in)
Engine idling speed 1,450 ~ 1,550 r/min
Intake vacuum 33.3 kPa (250 mmHg, 9.83 inHg)
Model YFM350X(P) 2002

–4 –
SPEC
MAINTENANCE SPECIFICATIONS
CHASSIS
ELECTRICAL
Model YFM350X(P) 2002
Brake lever and brake pedal:
Brake lever free play 0 mm (0 in) at lever end
Brake pedal position 10 mm (0.4 in)
Brake pedal free play 8 mm (0.315 in)
Model YFM350X(P) 2002
C.D.I.:
Magneto model/manufacturer F4T466/MITSUBISHI
Pickup coil resistance 459 ~ 561 Ωat 20 °C (68 °F)
(Color) (White/Red-White/Green)
Rotor rotation direction detection coil resis-
tance
0.083 ~ 0.101 Ωat 20 °C (68 °F)
(Color) (Red-White/Blue)
C.D.I. unit-model/manufacturer F8T38675/MITSUBISHI
Ignition coil:
Model/manufacturer 2JN/YAMAHA
Minimum spark gap 6 mm (0.24 in)
Primary winding resistance 0.18 ~ 0.28 Ωat 20 °C (68 °F)
Secondary winding resistance 6.32 ~ 9.48 kΩat 20 °C (68 °F)
Charging system:
Model/manufacturer F4T466/MITSUBISHI
Nominal output 14 V 15 A at 5,000 r/min
Charging coil resistance/color 0.51 ~ 0.63 Ωat 20 °C (68 °F)/White-White
0.47 ~ 0.57 Ωat 20 °C (68 °F)/White-White
Rectifier/regulator:
Regulator type Semi conductor-short circuit
Model/manufacturer SH640-11/SHINDENGEN
No load regulated voltage 14.1 ~ 14.9 V
Rectifier capacity 14 A
Withstand voltage 200 V
Starter relay:
Model/manufacturer MS5D-611/JIDECO
Amperage rating 100 A
Coil winding resistance 3.9 ~ 4.7 Ω

–5 –
SPEC
CABLE ROUTING
1Clutch switch
2Rear brake cable
3Clutch cable
4Front brake hose
5Front brake light switch
6Throttle cable
7Band
ÈInstall the fuel tank breather hose into the hole of
the handlebar cover.
CABLE ROUTING

–6 –
SPEC
1Main switch lead
2Handlebar switch lead
3Clutch switch lead
4Park switch lead
5Front brake light switch lead
6Fuel tank breather hose
CABLE ROUTING

– 7 –
SPEC
1Starter relay
2Neutral relay
3Tail/brake light
4CDI unit
5Rectifier/regulator
6Fuse
7Battery breather hose
ÈPass the battery breather hose through the inside
of the frame bracket.
ÉPass the battery breather hose through the guide.
CABLE ROUTING

–8 –
SPEC
1Battery negative lead
2Rear brake light switch
3Drive select lever switch
4Rear brake cable
5Rear brake hose
6Rectifier/regulator
7CDI unit
8Carburetor overflow hose
9Rear brake light switch lead
ÈPass the wire harness and starter motor lead
through the holder.
ÉFasten the wire harness, starter motor lead and
handlebar switch lead with the band.
CABLE ROUTING

– 9 –
CHK
ADJ
INTRODUCTION/
PERIODIC MAINTENANCE/LUBRICATION INTERVALS
EB300000
PERIODIC CHECKS AND ADJUSTMENTS
INTRODUCTION
This chapter includes all information necessary to perform recommended inspections and adjust-
ments. These preventive maintenance procedures, if followed, will ensure more reliable vehicle
operation and a longer service life. The need for costly overhaul work will be greatly reduced. This
information applies to vehicles already in service as well as to new vehicles that are being prepared
for sale. All service technicians should be familiar with this entire chapter.
EB301000
PERIODIC MAINTENANCE/LUBRICATION INTERVALS
* It is recommended that these items be serviced by a Yamaha dealer.
** Lithium-soap-based grease
ITEM ROUTINE
INITIAL EVERY
1
month
3
months
6
months
6
months
1
year
Valves* • Check valve clearance.
• Adjust if necessary.
Spark plug
• Check condition.
• Adjust gap and clean.
• Replace if necessary.
Air filter •Clean.
• Replace if necessary.
Every 20 ~ 40 hours
(More often in wet or dusty areas.)
Carburetor* • Check idle speed/starter operation.
• Adjust if necessary.
Crankcase breather
system*
• Check breather hose for cracks or damage.
• Replace if necessary.
Exhaust system*
• Check for leakage.
• Tighten if necessary.
• Replace gasket(s) if necessary.
Fuel line* • Check fuel hose for cracks or damage.
• Replace if necessary.
Engine oil • Replace (Warm engine before draining).
Engine oil filter
element
•Clean.
• Replace if necessary.
Engine oil strainer •Clean.
Drive chain • Check and adjust slack/alignment/clean/lube.
Brakes* • Check operation/fluid leakage/See NOTE Page 10.
• Correct if necessary.
Clutch* • Check operation.
• Adjust if necessary.
Wheels* • Check balance/damage/runout.
• Replace if necessary.
Wheel bearings* • Check bearing assembly for looseness/damage.
• Replace if damaged.
Steering system*
• Check operation.
• Repair if damaged.
• Check toe-in.
• Adjust if necessary.
Upper and lower arm
pivot and steering
shaft*
• Lubricate every 6 months.**
Rear arm pivot* • Lubricate every 6 months.**
Fittings and
Fasteners*
• Check all chassis fittings and fasteners.
• Correct if necessary.
Battery*
• Check specific gravity.
• Check breather pipe for proper routing.
• Correct if necessary.

–10 –
CHK
ADJ
PERIODIC MAINTENANCE/LUBRICATION INTERVALS
NOTE:
●Recommended brake fluid: DOT4
●Brake fluid replacement:
1.When disassembling the master cylinder or caliper, replace the brake fluid. Normally check the
brake fluid level and add fluid as required.
2.On the inner parts of the master cylinder and caliper, replace the oil seals every two years.
3.Replace the brake hoses every four years, or if cracked or damaged.

–11 –
CHK
ADJ
ADJUSTING THE FRONT BRAKE/
ADJUSTING THE REAR BRAKE LIGHT SWITCH
CHASSIS
ADJUSTING THE FRONT BRAKE
1.Check:
●Brake lever free play a
Out of specification →Bleed the front brake
system.
Refer to “AIR BLEEDING (HYDRAULIC
BRAKE SYSTEM)”in CHAPTER 3. (Manual
No.: 3GD-AE5)
ADJUSTING THE REAR BRAKE LIGHT
SWITCH
NOTE:
The rear brake light switch is operated by
movement of the brake pedal.
The rear brake light switch is properly adjusted
when the brake light comes on just before the
braking effect starts.
Brake lever free play (at brake
lever end):
0 mm (0 in)
1.Check:
●Rear brake light operation timing
Incorrect →Adjust.
2.Adjust:
●Rear brake light operation timing
***********************************************
●Hold the main body 1of the rear brake light
switch so that it does not rotate and turn the
adjusting nut 2in direction aor buntil the
rear brake light comes on at the proper time.
***********************************************
Direction aBrake light comes on
sooner.
Direction bBrake light comes on
later.

–12 –
CHAS
FRONT SUSPENSION
CHASSIS
FRONT SUSPENSION
1Thrust cover
2Bushing
3Front upper arm
4Collar
5Front lower arm
6Shock absorber
7Steering knuckle