Bad Boy 1500 User manual

All information contained within this publication is based on the
latest product information at the time of publication. Due to
constant improvements in the design and quality of production
components, some minor discrep ancies may result between the
actual vehicle and the information presented in this publi cation.
Model 1500
(Gas Powered)
Multi-Terrain Vehicle
(MTV)
Service Manual

PAGE 2
SERVICE MANUAL
This service manual contains the technical data of each component inspection and repair for the MTV
(Multi-Terrain Vehicle) by Bad Boy Mowers. The manual is shown with illustrations and focused on “Service
Procedures,” “Operation Key Points,” and “Inspection Adjustment” which provides technician with service
guidelines.
All information contained within this publication is based on the latest product information at the time of
publication. Due to constant improvements in the design and quality of production components, some minor
discrep ancies may result between the actual vehicle and the information presented in this publi cation.
Depictions and/or procedures in this publication are intended for reference use only. No liability can be accepted
for omissions or inaccuracies. Any reprinting or reuse of the depictions and/or procedures contained within,
whether whole or in part, is expressly prohibited.
Bad Boy, Inc.
102 Industrial Drive
Batesville, Arkansas 72501
United States of America

PAGE 3
HOW TO USE THIS MANUAL
This service manual describes basic information of different system parts and system
inspection & service for the Bad Boy MTV.
In addition, please refer to the manual contents for details on servicing, inspecting and adjusting
the Bad Boy MTV.
Chapter 1 Page 4 covers general information and troubleshooting diagnosis.
Chapter 2 Page 24 covers the service maintenance information and special tools manual.
Chapters 3 - 11 Page 36 cover engine and driving systems.
Chapter 12 Page 100 covers the cooling system.
Chapters 13 -14 Page 107 covers the frame and body assembly.
Chapter 15 Page 122 covers the electrical equipment and the wiring diagram.

PAGE 4
SERVICE MANUAL
Chapter CONTENTS
1 GENERAL INFORMATION
2 SERVICE MAINTENANCE INFORMATION
3 LUBRICATION SYSTEM
4 FUEL SYSTEM
5 ENGINE REMOVAL
6 CYLINDER HEAD/VALVE
7 CYLINDER/PISTON
8 “V” TYPE BELT DRIVING SYSTEM
9 FINAL DRIVING MECHANISM
10 ALTERNATOR / STARTING CLUTCH
11 CRANKSHAFT / CRANKCASE
12 COOLING SYSTEM
13 FRONT BRAKE AND FRONT WHEEL
14 STEERING / FRONT SUSPENSION
15 REAR BRAKE/REAR WHEEL / REAR CUSHION
16 ELECTRICAL EQUIPMENT
17 ELECTRICAL DIAGRAM

PAGE 5
Serial Number on MTV
PIN Number:
Located under seat on passenger side.

PAGE 6
SERVICE MANUAL
CHAPTER 1 GENERAL INFORMATION/TROUBLESHOOTING
General Safety .........................................................pages 6–7
Service Precautions ...................................................page 8–11
Specifications ..........................................................pages 12–13
Torque Values ..........................................................pages 14 –15
Troubleshooting/Diagnosis ..........................................page 16 – 23
General Safety
Carbon Monoxide Warning
If you must run your engine, ensure the place is well ventilated. Never run your engine in a closed area.
CAUTION
Exhaust contains toxic gas which may cause unconsciousness and even result in death.
Gasoline
Gasoline has a low ignition point and is an explosive material. Work in a well-ventilated area, no flame or spark
should be allowed in the work place or anywhere near where gasoline is being stored.
CAUTION
Gasoline is highly flammable, and may explode under some conditions, keep it away from children.
CAUTION
Used Engine Oil - Prolonged contact with used engine oil (or transmission oil) may cause skin cancer although
it might not be verified. We recommend that you wash your hands with soap and water right after contacting.
Keep used oil beyond reach of children.

PAGE 7
CAUTION
Hot Components - Components of the engine and exhaust system can become extremely hot after engine
running. They remain very hot even after the engine has been stopped for some time. When performing service
work on these parts, wear insulated gloves and wait until cooling off.
CAUTION
Battery - Battery emits explosive gases; flame is strictly prohibited. Keep the work area well ventilated when
charging the battery. The battery contains sulfuric acid (electrolyte) which can cause serious burns, so be
careful. Avoid contact with your eyes and skin. If you get battery acid on your skin, wash immediately with
water. If you get battery acid in your eyes, wash immediately with water and then see a doctor.
Brake shoe quick tip:
Do not use an air hose or a dry brush to clean components of the brake system; use a vacuum cleaner or
equivalent to avoid flying dust.
CAUTION
Brake Shoe Caution - Inhaling brake shoe or pad ash or dust may cause disorders or cancer.
CAUTION
Brake Fluid Caution - Spilling brake fluid on painted, plastic, or rubber parts may cause damage to the parts.
Place a clean towel on the above-mentioned parts for protection when servicing the brake system. Keep the out
of reach of children. Brake fluid is hygroscopic which means it absorbs moisture from the surrounding air. For
this reason, we recommend that the reservoir cap is always secured. When filling the reservoir, leave the cap off
only long enough to fill the reservoir to the appropriate level then re-secure the cap.

PAGE 8
SERVICE MANUAL
Service Precautions
Always use with Bad Boy genuine parts and recommended oils. Using non-recommended parts for the Bad Boy
MTV may damage the Vehicle.
Special tools are designed for removal and installation of engine components without damage. Using the wrong
tools may result in damage to the parts.
When servicing this MTV, be sure to select appropriate tools. This machine uses both Metric and English
system bolts, screws, nuts, etc. Using improper tools can damage components.
Clean the outside of the parts or the cover before removing it from the MTV. Otherwise, dirt and deposits
accumulated on the part’s surface may fall into the engine, chassis, or brake system and cause damage.
Wash and clean parts with high ignition point solvent, and blow dry with compressed air. Pay special attention
to O-rings or oil seals because most cleaning agents have an adverse effect on them.
Never bend or twist a control cable to prevent cable damage or premature wear.
Old rubber parts may become deteriorated and prone to damage by solvent and oil. Check these parts before
installation to make sure that they are in good condition, replace if necessary.
When loosening a component which has different sized fasteners, work with a diagonal pattern and from inside
out. Loosen the small fasteners first. If the bigger ones are loosen first, small fasteners may receive too much
stress.
Store complex components such as transmission parts in the proper assembled order and tie them together
with wire for ease of installation later.
Note the position of components before disassembling them to ensure they will be reassembled in correct
order. (depth, distance or position).
Components not to be reused should be replaced when disassembled including gaskets metal seal rings,
O-rings, oil seals, snap rings, and split pins.

PAGE 9
General Information
If the length of
bolts and screws
for assemblies,
cover plates or
boxes is different
from one another,
be sure they
are correctly
installed. In case
of confusion,
Insert the bolt into the hole to compare its length with
other bolts, if its length out side the hole is the same
with other bolts, it is a correct bolt. Bolts for the same
assembly should have the same length.
Tighten assemblies with different dimension fasteners
as follows: Tighten all the fasteners with fingers,
then work diagonally
from inside toward
outside, important
components should
be tightened 2 to 3
times with appropriate
increments to avoid
warp unless otherwise
indicated. Bolts and
fasteners should be kept clean and dry. Do not apply
oil to the threads.
When oil seal is installed, fill the groove with grease,
install the oil seal
with the name of
the manufacturer
facing outside, and
check the shaft on
which the oil seal is
to be installed for
smoothness and for burrs that may damage the oil
seal.
Remove residues
of the old gasket
or sealant before
reinstallation,
grind with a
grindstone if the
contact surface
has any damage.
The ends of
rubber hoses for
fuel, vacuum, or
coolant should
be pushed as far
as they can go to
their connections
so that there is enough room below the enlarged ends
for tightening the clamps.
Rubber and plastic
boots should be
properly reinstalled
to the original correct
positions as designed.
The tool should be
pressed against two (inner and outer) bearing races
when removing a ball bearing. Damage may result if
the tool is pressed against only one race (either inner
race or outer race). In this case, the bearing should be
replaced. To avoid damaging the bearing, use equal
force on both races.
Both of these examples can result in bearing damage.

PAGE 10
SERVICE MANUAL
General Information
Lubricate the
rotation faces
with specified
lubricant on
the lubrication
points before
assembling.
Check the
positions and
operation of
installed parts
is in correct
and properly.
Before battery removal make sure to remove the
battery negative (-) cable first. Note - make sure
tools like open-ended
wrenches do not make
contact with the body.
This prevents the
circuit from shorting
and creating spark.
After service is
completed, make sure
all connection points
are secured. Battery
positive (+) cable
should be connected
first. The two
battery posts have
to be greased after
connected the cables.
Make sure that the battery
post caps are placed in
their proper position after
the battery posts have
been serviced.
When separating a
connector, its locker
needs to be unlocked first.
Then, conduct the service
operation.
Do not pull the wires when disconnecting a connector
or wires. Hold the connector body.
Check to see if
the connector
pins are bent or
loose.
Insert the connectors completely. If there are two
locks on two connector sides, make sure the locks are
locked in properly.
Check to see if any
wires are loose.
If the connector is
covered by a
twin connector
boot, then
secure it
properly.
Before
terminal
connection,
check to see
if the boot is cracked or the terminal is loose.
Insert the
terminal
completely.

PAGE 11
Secure wires and
wire harnesses
to the frame with
wire bands at
the designated
locations. Tighten
the bands so that only the insulated surfaces contact
the wires or wire harnesses.
Wire band and wire
harness must be
clamped and secured
properly.
Do not squeeze
wires against the
weld or its clamp.
Do not let the wire
harness contact with
rotating, moving or
vibrating components
while routing the
harness.
Keep wire
harnesses far
away from hot
parts.
Route wire harnesses to avoid sharp edges or corners
and also avoid the projected ends of bolts and screws.
Route harnesses so that
they neither pull too tight
nor have excessive slack.
Protect
wires and wire harnesses with
electrical tape or tube to protect
them from contact with a sharp edge or corner.
Thoroughly clean the surface where tape is to be
applied.
Secure the rubber boot
firmly when applying it to
wire harness.
Never use wires or
harnesses on which
the insulation has been
broken. Wrap electrical
tape around the damaged
parts or replace them.
Never clamp or squeeze
the wire harness
while installing other
components.
Do not let the wire harness become twisted during
installation.
Before operating a test instrument, operator should
read the operation manual for the instrument.
Conduct the test in accordance with the instructions.
Clean rust with sand paper on connector pins/
terminals if found. Conduct connection operation.

PAGE 12
SERVICE MANUAL
Specifications
Engine:
Type ..................................4 Stroke Engine
Installation and Arrangement ....Vertical, Below Center, Incline
Fuel Used ...........................87 Octane Unleaded
Cycle/Cooling .......................4-Stroke Water Cooled
Displacement ............................. 403.1
Compression Ratio ................ 9.2 : 1
Maximum HorsePower ...........28 / 6500rpm
Maximum Torque .................. 18.8 ft.lbs / 4000rpm
Ignition ..............................C.D.I
Starting System ...................Electrical Starter with backup recoil starter
Air Filtration .......................Paper
Cylinder:
Bore ..................................Ø 86mm
Stroke ................................69.4 mm
Number/Arrangement .............Single Cylinder
Suspension System:
Front .................................Double Arm
Rear ..................................Unit Swing
Tire Specifications:
Front .................................25 x 8 x 12
Rear ..................................25 x 10 x 12
Rim is made of Steel

PAGE 13
Muffler ...........................................Expansion & Pulse Type
Exhaust Pipe Position and Direction .......Right side, and Backward Exhaust Concentration
Lubrication System ............................Forced Circulation & Splashing
Solid Particulate:
CO ........................................... Below 7.0g/km
HC ........................................... Below 1.5g/km
NOx .......................................... Below 0.4g/km
E.E.C. ....................................... None
P.C.V. ........................................ None
Catalytic Reaction Control System..... None
Brake System:
Front .................................Disk (Ø180mm)
Rear ..................................Disk (Ø200mm)
Performance:
Max Speed ..........................Up to 55 mph
Climb Ability ........................Below 25o
Reduction:
Primary Reduction .................Belt
Secondary Reduction .............. Gear / Shaft
Clutch ................................Centrifugal, wet-type
Transmission .......................C.V.T., Auto Speed Change

PAGE 14
SERVICE MANUAL
Torque Values
The torque values listed in the table below are more important torque values. Please see standard values for
those not listed in the table.
Standard Torque Values
Type Tighten Torque Type Tighten Torque
5 mm bolt 3-4 ft/ lbs
5 mm screw
2.5-3.5 ft/lbs
6 mm bolt 6-8 ft/ lbs
6 mm screw、SH nut
5-7 ft/lbs
8 mm bolt 13-18 ft/lbs
6 mm bolt、nut
7-10 ft/lbs
10 mm bolt 22-29 ft/ lbs
8 mm bolt、nut
17-21 ft/lbs
12 mm bolt 36-44 ft/ lbs
10 mm bolt、nut
25-33 ft/lbs
Engine Torque Values
Item QTY THREAD DIAMETER TORQUE VALUE REMARKS
Cylinder stud bolt
4 10 22-29 ft/lbs
Cylinder head nut
4 8 17-21 ft/lbs
Cylinder head right bolt
2 8 15-17 ft/lbs
Cylinder head side cover bolt
2 6 7-10 ft/lbs
Cylinder head cover bolt
4 6 7-10 ft/lbs
Cylinder head stud bolt (inlet pipe)
2 6 7-10 ft/lbs
Cylinder head stud bolt (EX. pipe)
2 8 17-21 ft/lbs
Air inject pipe bolt
4 6 7-10 ft/lbs
Tappet adjustment screw nut
4 5 5-7 ft/lbs Apply Oil To Thread
Spark plug
1 10 7-10 ft/lbs
Tensioner lifter bolt
2 6 7-10 ft/lbs
Carburetor insulator bolt
2 6 5-7 ft/lbs
Oil pump screw
2 3 2 ft/lbs
Water pump impeller
1 7 7-10 ft/lbs
Engine left cover bolt
9 6 8-12 ft/lbs
Engine oil draining bolt
1 12 25-33 ft/lbs
Engine oil strainer cap
1 30 9-12 ft/lbs
Mission draining bolt
8 8 8-12 ft/lbs
Mission filling bolt
1 12 25-33 ft/lbs
Shift drum fixing bolt
1 14 25-33 ft/lbs
Clutch driving plate nut
1 28 36-44 ft/lbs
Clutch outer nut
1 14 36-44 ft/lbs
Drive face nut
14 14 60-75 ft/lbs
ACG. Flywheel nut
1 14 36-44 ft/lbs
Crankcase bolts
7 6 6-8 ft/lbs
Mission case bolt
7 8 20-22 ft/lbs

PAGE 15
Frame Torque Values
ITEM QUANTITY THREAD DIAMETER TORQUE VALUE REMARKS
Knuckle nut 2 10 36
Tie rod lock nut 4 10 26
Front wheel nut 8 10 30
Front axle castle nut 2 14 36
Rear axle castle nut 2 14 36
Rear wheel nut 8 10 30
Engine hanger nut 4 12 34
Rear axle holder bolt 4 12 50
Drive gear bolt 2 10 34
Driven gear nut 4 10 34
Swing arm pivot bolt 1 14 50
Front suspension arm nut 4 10 36
Front / Rear cushion mounting bolt 6 10 30
Brake hose bolt 13 10 20
Brake disk mounting bolt 11 8 26
Air-bleed valve 3 5 3.5
Exhaust muffler mounting bolt 2 8 20
Exhaust muffler connection nut 2 7 20

PAGE 16
SERVICE MANUAL
Troubleshooting
A. Engine is hard to start or cannot be started
Check and Adjustment: Loosen carburetor drain bolt to see if there is gasoline inside the carburetor.
Fault Condition: If no fuel is supplied to carburetor then check the following probable
causes. IF FUEL SUPPLY IS SUFFICIENT CONTINUE TO NEXT CHECK AND
ADJUSTMENT.
Probable Causes: • Fuel tank valve turned off
• No fuel in fuel tank
• Check fuel lines, fuel tank, carburetor and intake vacuum.
• Float valve clogged
• Lines in fuel tank evaporation system clogged
• Malfunction of fuel pump
• Loosen or damaged fuel pump vacuum hose
• Fuel filter clogged
• Closed fuel tank cap
Check and Adjustment: Remove spark plug, install it into spark plug cap, and perform a spark test
against engine ground. Check to make sure it sparks properly. IF SPARK
PLUG IS FUNCTIONING PROPERLY CONTINUE TO NEXT CHECK AND
ADJUSTMENT.
Fault Condition: Weak sparks or no spark at all.
Probable Causes: • Malfunction of spark plug
• Spark plug foul
• Malfunction of CDI set
• Malfunction of AC generator
• Ignition coil is in open or short circuit
• Ignition coil leads open or short circuit
• Malfunction of main switch
Check and Adjustment: Perform cylinder compression test. IF CYLINDER COMPRESSION TEST IS
NORMAL CONTINUE TO NEXT CHECK AND ADJUSTMENT.
Fault Condition: Low Compression pressure or no pressure.
Probable Causes: • Piston ring seized
• Malfunction of cylinder valves
• Worn cylinder and piston ring
• Cylinder gasket leak

PAGE 17
Check and Adjustment: If there are no signs of ignition CONTINUE TO NEXT CHECK AND
ADJUSTMENT. If there are signs of ignition, but engine cannot be started then
check these probable causes:
Probable Causes: • Malfunction of throttle valve operation
• Air leak in intake manifold
• Incorrect ignition timing
Check and adjustment: Remove the spark plug and check it again. IF SPARK PLUG IS DRY
CONTINUE TO NEXT CHECK AND ADJUSTMENT.
Fault Condition: Spark plug is Wet
Probable Causes: • Fuel level in carburetor too high
• Malfunction of throttle valve operation
• Throttle valve opening too wide
Check and Adjustment: Remove carburetor and connect a hose onto fuel inlet. Then blow air into the
hose.
Check and Adjustment: Check to see if air is blowing
Fault Condition: Clogged
Probable Cause: Malfunction of float meter.
B. Sluggish Engine, Lack of Acceleration, Lack of Power
Try gradually accelerating to check engine speed.
Check and Adjustment: Check to see if engine speed can be increased.
Fault Condition: Engine speed cannot be increased.
Probable Causes: • Air cleaner clogged
• Poor fuel supply
• Lines in fuel tank evaporation system clogged
• Exhaust pipe clogged
• Fuel nozzle clogged in carburetor.
• Ignition timing incorrect

PAGE 18
SERVICE MANUAL
Check and Adjustment: Check ignition timing using ignition timing light.
Fault Condition: Incorrect engine timing.
Probable Causes: • Malfunction of CDI
• Malfunction of AC alternator
Check and Adjustment: Check cylinder compression pressure (using compression pressure
gauge)
Fault Condition: No compression pressure
Probable Causes: • Cylinder & piston ring worn out
• Cylinder gasket leaked
• Valve deterioration
• Seized piston ring
Check and Adjustment: Check to see if carburetor jet is clogged.
Fault Condition: Clogged
Probable Causes: Remove foreign object
Check and Adjustment: Remove spark plug.
Fault Condition: Fouled or Discolored
Probable Causes: • Remove dirt
• Incorrect spark plug heat range
Check and Adjustment: Check to see if the engine is overheating
Fault Condition: Engine Overheating
Probable Causes: • Piston and cylinder worn out
• Lean mixture
• Poor fuel quality
• Too much carbon deposited in combustion chamber
• Ignition timing too advanced
• Poor circuit on the cooling system

PAGE 19
Check and Adjustment: Continually drive in acceleration or high speed.
Fault Condition: Engine Knocking
Probable Causes: • Too much carbon deposited in combustion chamber
• Lean mixture
• Poor fuel quality
• Ignition timing too advanced
C. Engine runs Sluggish at low speeds or idling
Check and Adjustment: Check ignition timing using ignition lamp
Fault Condition: Abnormal
Probable Causes: • Incorrect ignition timing (malfunction of CDI or AC alternator)
Check and Adjustment: Adjust the air screw of the carburetor.
Fault Condition: Poor engine performance
Probable Causes: • Rich mixture (tighten the screw)
• Lean mixture (loosen the screw)
Check and Adjustment: Air leak through carburetor gasket
Fault Condition: Air leak
Probable Causes: • Bad heat insulation gasket
• Carburetor loose
• Bad intake gasket
• Bad carburetor O-ring
• Vacuum hose leak

PAGE 20
SERVICE MANUAL
Check and Adjustment: Remove spark plug, install spark plug into spark plug cap and perform
spark test against engine ground
Fault Condition: Poor spark
Probable Causes: • Spark plug fouled
• Malfunction of CDI
• Malfunction of AC generator
• Malfunction of ignition coil
• Open or short circuit in spark plug leads
• Malfunction of main switch
D. Engine runs Sluggish at high speeds
Check and Adjustment: Check ignition timing.
Fault Condition: Abnormal
Probable Causes: • Malfunction of CDI
• Malfunction of AC alternator
Check and Adjustment: Check fuel supplying system in fuel bowl
Fault Condition: Abnormal
Probable Causes: • Insufficient fuel in fuel tank
• Fuel filter clogged
• Restricted fuel tank vent
Check and Adjustment: Check if carburetor is clogged
Fault Condition: Clogged
Probable Causes: • Clean Carburetor