KYMCO Downtown 350i Operating instructions

KYMCO Repair Manual Downtown 350i
1
KYMCO Downtown 350i Service Manual
Using this manual
This manual has been designed to assist trained mechanics in servicing the
models listed above. If you do not have the proper training or tools to perform a
particular task it is best if you seek out a service professional.
This manual was written using the latest information available at the time of
publication. Illustrations in this manual are shown to help you with the basics of
performing the jobs listed. The pictures in this manual may not depict the actual
vehicle you’re working on, however the procedures will be similar.
Inexperienced technicians without the correct tools and knowledge may not be
able to perform these jobs as intended. Caution needs to be taken for the vehicle
and its operator as serious injury can occur. Always read a procedure in its
entirety before attempting any repairs.

KYMCO Repair Manual Downtown 350i
2
KYMCO reserves all rights to this publication and does not permit the
reproduction or use of this publication, in full or in part, in any manner without our
express written permission. No trademark or patent liability is assumed with
respect to the use of the information contained in this manual.
While the instructions, photographs and illustrations in this manual have been
reviewed for accuracy it is up to the individual performing the procedures to use
good judgement when performing any procedures described. Every precaution
has been taken in the manufacture of this manual however the publisher
assumes no responsibility for errors and omissions. Furthermore, no liability or
responsibility is assumed for damages to property or injury to persons resulting
from the use of the information contained in this guide. Use of this information to
perform service procedures is done entirely at your own risk.

KYMCO Repair Manual Downtown 350i
3
1. Quick Reference
This chapter provides a quick reference source of technical specifications and
information for KYMCO Downtown 350i models.
Component Location .....................................................................1-2
Special Tools ..................................................................................1-6
Specifications .................................................................................1-7
Torque Specifications ....................................................................1-19
Troubleshooting .............................................................................1-22
VIN and Engine Number Location ................................................1-27
2.Periodic Maintenance
This chapter covers the periodic maintenance for the KYMCO Downtown 350i.
Maintenance Schedule .......................................................2-2
Air Filter Servicing ..............................................................2-4
Brake Fluid ...........................................................................2-6
Brake Inspection .................................................................2-13
Engine Compression Test ..................................................2-15
Coolant Level Check ...........................................................2-17
Engine Oil .............................................................................2-21
General Lubrication ............................................................2-36
Hose Inspection ..................................................................2-37
Side Stand ............................................................................2-38
Spark Plug ............................................................................2-40
Steering ................................................................................2-43
Suspension ..........................................................................2-44
Throttle Free Play ................................................................2-46
Tires ......................................................................................2-52
Final Drive Oil ......................................................................2-54
Valve Clearance ...................................................................2-60

KYMCO Repair Manual Downtown 350i
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3.External Components
This chapter covers the location and servicing of the external components for the
KYMCO Downtown 350i model.
REAR PART
Seat .................................................................................................3-3
Luggage Box ..................................................................................3-7
Rear Carrier ....................................................................................3-9
Rear Center Cover ..........................................................................3-10
Body Cover .....................................................................................3-11
Rear Inner Fender ..........................................................................3-16
Rear Tire Fender ............................................................................3-17
Heat Shield .....................................................................................3-18
Exhaust System .............................................................................3-20
4.Engine
This chapter covers the location and servicing of the engine components for the
KYMCO Downtown 350i model.
Cylinder Head Cover ......................................................................4-5
Camshaft .........................................................................................4-8
Cylinder Head .................................................................................4-23
Valves ..............................................................................................4-31
Cylinder and Piston .......................................................................4-37
Starter Clutch .................................................................................4-62
Generator ........................................................................................4-69
Oil Pump .........................................................................................4-73
Crankcase .......................................................................................4-77
Crankshaft ......................................................................................4-87
Engine Removal .............................................................................4-90

KYMCO Repair Manual Downtown 350i
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5.Cooling System
This chapter covers the location and servicing of the cooling system components
for the KYMCO Downtown 350i model.
Coolant ............................................................................................5-3
Radiator ..........................................................................................5-12
Water Temperature Sensor (WTS) ................................................5-22
Water Pump ....................................................................................5-28
6.Fuel Injection System
This chapter covers the location and servicing of the fuel system components for
the KYMCO Downtown 350i model.
Airbox ..............................................................................................6-4
Fuel Tank ........................................................................................6-8
Fuel Pump .......................................................................................6-13
Throttle Body Removal ..................................................................6-21
Throttle Cable .................................................................................6-32
Throttle Body ..................................................................................6-35
Fuel Injector ....................................................................................6-41
TPS ISC Reset Procedure ..............................................................6-46
Self-Diagnosis ................................................................................6-47
F.I. Diagnostic Tool ........................................................................6-54
7.CVT Continuously Variable Transmission
This chapter covers the location and servicing of the CVT components for the
KYMCO Downtown 350i model.
Belt Case .........................................................................................7-2
CVT Removal ..................................................................................7-7
CVT Installation ..............................................................................7-26

KYMCO Repair Manual Downtown 350i
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8.Final Drive
This chapter covers the location and servicing of the final drive components for
the KYMCO Downtown 350i model.
Final Drive Oil .................................................................................8-3
Final Reduction ..............................................................................8-8
9.Electrical Systems
This chapter covers the location and servicing of the electrical systems for the
KYMCO Downtown 350i model.
Electrical Specifications ................................................................9-8
Fuses ...............................................................................................9-10
ECU Removal .................................................................................9-11
Ignition System ..............................................................................9-15
Charging System ...........................................................................9-22
Battery .............................................................................................9-24
Relays .............................................................................................9-28
Starting System ..............................................................................9-30
Starter Motor ..................................................................................9-34
Switches .........................................................................................9-36
Lights ..............................................................................................9-48
Horn .................................................................................................9-56

KYMCO Repair Manual Downtown 350i
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10.Brakes
This chapter covers the location and servicing of the brake system components
for the KYMCO Downtown 350i model.
Brake Pad Replacement ................................................................10-2
Master Cylinders ............................................................................10-13
Master Cylinders ............................................................................10-22
Front Brake Caliper ........................................................................10-26
Rear Brake Caliper .........................................................................10-31
Brake Disc ......................................................................................10-37
ABS ...................................................................................................10-42
11.Steering
This chapter covers the location and servicing of the steering components for the
KYMCO Downtown 350i model.
Handlebar .......................................................................................11-2
Grips ................................................................................................11-8
Steering stem .................................................................................11-8
12.Front Suspension
This chapter covers the location and servicing of the front fork components for
the KYMCO Downtown 350i model.
Front Fork Removal .......................................................................12-2
Front Fork Installation ...................................................................12-6
Fork Disassembly ..........................................................................12-8
Fork Assembly ...............................................................................12-17

KYMCO Repair Manual Downtown 350i
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13.Rear Suspension
This chapter provides information on the rear suspension components of the
KYMCO Downtown 350i model.
Shock Absorbers ...........................................................................13-2
Rear Fork..........................................................................................13-8
14.Wheels
This chapter covers the location and servicing of the wheels for the KYMCO
Downtown 350i model.
Bearing Replacement ....................................................................14-2
Front Wheel ....................................................................................14-6
Rear Wheel .....................................................................................14-11
Wheel Inspection ............................................................................14-19
Wheel Specifications .....................................................................14-21

1.Quick Reference Downtown 350i
1-1
1. Quick Reference
This chapter provides a quick reference source of technical specifications and
information for KYMCO Downtown 350i models.
Component Location .....................................................................1-2
Special Tools ..................................................................................1-5
Specifications .................................................................................1-6
Torque Specifications ....................................................................1-19
Troubleshooting .............................................................................1-22
VIN and Engine Number Location ................................................1-27

1.Quick Reference Downtown 350i
1-2
Component Location
Radiator Cap
Horn
Winker Relay
(Turn Signal)
Relays
Tilt Switch
Oil Pressure
Controller
Coolant Reserve
Tank
Meter Instrument
Couplers

1.Quick Reference Downtown 350i
1-3
Component Location
Regulator/Rectifier
Starter Relay
EFI ECU
Ignition Coil
Coolant Reserve
Tank
Ignition Switch
Radiator
Oxygen Sensor
Stator and CPS

1.Quick Reference Downtown 350i
1-4
Component Location
Throttle Body
ISC
TPS
MAP Sensor
Fuel Injector
WTS
Fuel Pump
Spark Plug
Air Temperature
Sensor
Wheel Speed
Sensor
ABS ECU

1.Quick Reference Downtown 350i
1-5
Special Tools
SPECIAL TOOLS
ITEM
TOOL NO.
DESCRIPTION
FLYWHEEL PULLER
A120E00003
Flywheel Puller (M28x1)
TAPPET ADJUSTER
A120E00012
Adjusting valve clearance
OIL SEAL & BEARING DRIVER
A120E00014
General Driver Set
UNIVERSAL HOLDER
A120E00021
Holding clutch pulley and flywheel
#41 NUT AND FITTING TOOL
A120E00028
Clutch disassembly
THREAD PROTECTOR
A120E00029
Crankshaft thread protector
BEARING PULLER
A120E00037
General Puller Set
VALVE COTTER INSTALLER
A120E00051
Valve cotter installation
CLUTCH SPRING COMPRESSOR
A120E00053
Clutch disassembly
STEERING STEM LOCK NUT
WRENCH (32 mm)
F002
Steering stem removal & installation

1.Quick Reference Downtown 350i
1-6
KYMCO Downtown 350i Specifications
General Information
Name (Model Code)
Downtown 350i (ACD5)
Overall length (mm)
2250
Overall width (mm)
780
Overall height (mm)
1310
Wheel base (mm)
1553
Engine type
4 stroke OHC
Displacement (cc)
321
Fuel recommended
90 # nonleaded gasoline
Curb weight (kg)
Front wheel
78
Rear wheel
111
Total
189
Max. weight capacity (kg)
Front wheel
130
Rear wheel
234
Total
364
Tires
Front wheel
120/80-14
Rear wheel
150/70-13
Ground clearance (mm)
140
Performance
Braking distance (m)
7.9m / 40 km/hr
Min. turning radius (m)
2.5

1.Quick Reference Downtown 350i
1-7
Engine
Starting system
Starting motor
Type
Gasoline, 4-stroke
Cylinder arrangement
SINGLE CYLINDER
Combustion chamber type
Semi-sphere
Valve arrangement
O.H.C. Chain drive
Bore x stroke (mm)
75.3 x 72
Compression ratio
10.7
Compression pressure
12 (kg/cm2)
Max. Horsepower
30.05/7500 PS/rpm
Max. Torque
3.2 / 5750 Kg-m/rpm
Valve timing
Intake
Open
9.5°BTDC
Close
37.5°ABDC
Exhaust
Open
40°BBDC
Close
10°ATDC
Valve clearance (cold) (mm)
Intake
0.10
Exhaust
0.10
Idle speed (rpm)
1600 ± 100
Lubrication System
Lubrication type
Forced pressure & Wet pump
Oil pump type
Inner/outer rotor type
Oil filter type
Full-flow filtration
Oil capacity
1.5 liter
Cooling Type
Liquid cooling

1.Quick Reference Downtown 350i
1-8
Fuel System
Air cleaner type & No
Paper element, wet
Fuel capacity
12.5 liter
Injection
Brand
Keihin
Type
Throttle body
Venturi dia.(mm)
34
Fuel pump pressure
3 Bar
Electrical Equipment
Ignition System
Type
ECU
Spark plug
Spec.
CR7E (NGK)
Gap
0.6-0.7 mm
Battery Capacity
12V10AH
Power Drive System
Clutch Type
Dry multi-clutch
Transmission Gear
Type
CVT
Operation
Automatic centrifugal type
Reduction Gear
Type
Two-stage reduction
Reduction ratio
1st
2.24 ~ 0.72
2nd
7.222
Moving Device
Tire type
Tubeless
Wheel material
Aluminum
Tire pressure
Kg/cm2(psi)
Front
2.0 (28.4)
Rear
2.25 (32)
Handle turning angle(L/R)
Left
40°
Right
40°
Brake system type
Front
Disc brake
Rear
Disc brake
Damping Device
Suspension type
Front
Telescope
Rear
Swing arm
Shock absorber stroke
Front
110 mm
Rear
100 mm
Frame type
UNDER BONE

1.Quick Reference Downtown 350i
1-9
ENGINE
Throttle grip free play
2 ~ 6 mm
Spark plug
NGK: CR7E
Spark plug gap
0.6 mm ~ 0.7 mm
Valve clearance
IN: 0.10 mm
EX: 0.10 mm
Idle speed
1600 ± 100 rpm
Cylinder compression
12 ± 2 kg/cm2
Ignition timing
ECU
Coolant type
Coolant type
Engine oil capacity:
At disassembly
1.5 Liter
At change
1.3 Liter
Gear oil type:
SAE 90
Gear oil capacity:
At disassembly
0.23 Liter
At change
0.21 Liter
Coolant capacity:
Radiator and hose with cool coolant
870 cc
Reserve tank
490 cc

1.Quick Reference Downtown 350i
1-10
Engine
Item
Standard (mm)
Valve clearance (cold)
IN
0.10
EX
0.10
Camshaft cam height
IN
34.2987
EX
34.1721
Valve rocker arm I.D.
IN
10.00 - 10.015
EX
10.00 - 10.015
Valve rocker arm shaft O.D.
IN
9.972 - 9.987
EX
9.972 - 9.987
Valve seat width
IN
1.2
EX
1.2
Valve stem O.D.
IN
4.990 - 4.975
EX
4.970 - 4.955
Valve guide I.D.
IN
5.00 - 5.012
EX
5.00 - 5.012
Valve stem-to-guide clearance
IN
0.010 - 0.037
EX
0.030 - 0.057

1.Quick Reference Downtown 350i
1-11
Item
Standard (mm)
Cylinder
I.D.
75.3
Taper limit
0.05
Out of round limit
0.05
Piston,
piston ring
Ring-to-groove clearance
Top
0.015 - 0.055
Second
0.015 - 0.055
Ring end gap
Top
0.10 - 0.25
Second
0.10 - 0.25
Oil side rail
0.2 - 0.7
Piston O.D.
Piston O.D. measuring point
9 mm from bottom of skirt
Piston-to-cylinder clearance
0.101 - 0.040
Piston pin hole I.D.
15.002 - 15.008
Piston pin O.D.
14.994 - 15.000
Piston-to-piston pin clearance
0.002 - 0.014
Connecting rod small end I.D. Bore
15.016 - 15.034
Item
Standard (mm)
Service Limit (mm)
Crankshaft
Connecting rod big
end side clearance
0.15 - 0.35
0.6
Connecting rod big
end radial clearance
0 - 0.008
0.05
Bearing Color
Crankcase mark
Crankshaft mark
A
B
C
D
A
black
green
green
red
B
green
green
red
---
Item
Service Limit (mm)
Starter drive gear I.D.
22.15
Starter drive gear O.D.
41.50

1.Quick Reference Downtown 350i
1-12
CVT
Item
Standard (mm)
Service Limit (mm)
Clutch lining thickness
4.0
2.0
Clutch outer I.D.
152.1 - 152.2
152.2
Weight roller O.D (Drive Pulley)
19.92 - 20.08
20.08
Cooling System
Radiator cap relief pressure
0.9 ± 0.15 kg/cm2(12.8 ± 2.1 psi)
Thermostat temperature
Begins to open
71 °C
Full-open
80 °C
Valve lift
3.5 - 4.5 mm
COOLANT MIXTURE (WITH ANTI-RUST AND ANTI-FREEZING EFFECTS)
Freezing
Point
Mixing
Rate
KYMCO SIGMA Coolant
Concentrate
Distilled
Water
-9°C
20%
344 cc
1375 cc
-15°C
30%
516 cc
1203 cc
-25'°C
40%
688 cc
1031 cc
-37°C
50%
860 cc
859 cc
-44.5°C
55%
945 cc
774 cc