ATK 125 LQ 1999 User manual

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Congratulations on your purchase of an American-made ATK motorcycle. This manual explains operation,
inspection, basic maintenance and tuning of your machine. All information in this manual is based on the latest
product information available at the time of publication. If you have any questions about this manual or your
machine, please contact yourATK dealer.
We recommend that you read this manual carefully and thoroughly before operating your new motorcycle. You
should also adhere to the recommended safety checks and maintenance schedules described within this manual.
IMPORTANT NOTICE
This machine is designed strictly for competition use, on a closed course. It is illegal for this machine to be operated on any public
street, road or highway. Off-road use on public lands may also be illegal. Please check local regulations before riding.
Please read this manual carefully and completely before operating this machine. Do not attempt to operate this machine until you
have attained a satisfactory knowledge of its controls and operating features, and until you have been trained in safe and proper
riding techniques. Regular inspections and careful maintenance, along with good riding skills, will ensure that you safely enjoy the
capabilities and the reliability of this machine.
More detailed service and parts manuals may be obtained from your local ATK dealer.
SAFETY INFORMATION
1. This machine is to be operated by an experienced rider only. Do no attempt to operate this machine at maximum power
until you are totally familiar with its characteristics.
2. This machine is designed to be ridden by the operator only. Do not carry passengers on this machine.
3. Always wear protective apparel. When operating this machine, always wear an approved helmet with goggles or a face
shield. Also, wear heavy boots, gloves, and protective clothing. Always wear proper fitting clothing that will not be
caught in any moving parts or controls of the machine.
4. For safety and reliability, the machine must be properly maintained. Always perform the pre-ride inspection indicated in
this manual. Correcting a mechanical problem before you ride may prevent an accident.
5. Gasoline is highly flammable and can cause injury or death. Always turn off the engine while refueling. Take care not to
spill any gasoline on the engine or exhaust system. Never refuel in the vicinity of an open flame, or while smoking. If
you should swallow gasoline, inhale excess gasoline vapors or allow gasoline to get into your eyes, contact a doctor
immediately.
6. Operate the machine in an area with adequate ventilation. Exhaust fumes are poisonous. The fumes contain carbon
monoxide, which by itself is odorless and colorless. Carbon monoxide is a dangerous gas which can cause
unconsciousness or can be lethal.
7. Park the machine carefully.
8. Properly secure the machine before transporting it. When transporting the machine in another vehicle, always be sure it is
properly secured in an upright position. Otherwise, fuel may leak out of the carburetor or fuel tank.
CAUTION: INDICATES A POSSIBILITY OF PERSONAL INJURY IF INSTRUCTIONS ARE NOT FOLLOWED.
Note: Helpful Information

V I E W S 1
260 LQ 1
250 LQ 1
S P E C I F I C A T I O N S 2
General 2
Torque/Tool 3
C O N T R O L S 4
Throttle 4
C l u t c h L e v e r 4
F r o n t B r a k e L e v e r 4
Kill Switch 4
Handlebar Adjustment 4
Choke 4
F u e l P e t c o c k s 4
Fuel Level 5
G e a r S h i f t e r 5
R e a r B r a k e P e d a l 5
Exhaust Valve 5
Gearing 6
F o r k s 6
S h o c k 7
Rebound 7
Preload 7
P R E - R I D E / B R E A K I N 8
Engine and Transmission 8
B r a k e s 8
Suspension 8
F U E L / S TA R T I N G P R O C E D U R E 9
Fuel 9
Cold Engine 9
W a r m E n g i n e 9
M A I N T E N A N C E 1 0
Cleanliness 10
Periodic Maintenance Chart 10
Engine OH Change 11
Clutch Adjustment 11
Ignition 11
D r i v e C h a i n Te n s i o n C h e c k 1 1
Drive Chain Tension Adjustment 12
Drive Chain 12
D r i v e S p r o c k e t s 1 3
T h r o t t l e a n d C o n t r o l L e v e r s 1 3
Control Cables 13
A i r F i l t e r 1 3
Steering Head 14
S p a r k P l u g 1 4
SUSPENSION 15
Suspension Adjustment 15
R e a r S u s p e n s i o n S a g 1 5
Race Sag 15
Free Sag 15
S h o c k C o m p r e s s i o n D a m p i n g 1 6
Shock Rebound Damping 16
F o r k s 1 7
Compression Damping 17
Rebound Damping 17
F o r k O i l R a t i n g 1 7
F o r k O i l L e v e l 1 7
E f f e c t s o f F o r k O i l L e v e l 1 7
TABLE OF CONTENTS ^
S e t t i n g t h e F o r k O H L e v e l 1 8
C h a n g i n g F o r k O H 1 9
B R A K E S 2 0
Brake Fluid 20
B r a k e P a d s 2 0
Front Brake Pad Replacement 20
Front Brake Pad Installation 20
R e a r B r a k e P a d R e m o v a l 2 1
R e a r B r a k e P a d I n s t a l l a t i o n 2 1
Brake Bleeding 21
B r a k e R o t o r C o n d i t i o n 2 2
B r a k e R o t o r T h i c k n e s s 2 2
B r a k e P a d a n d R o t o r D e g l a z i n g 2 2
CARBURETOR 23
250 Carburetor Specifications 23
Explanation of the Different Jet Systems 24
P i l o t S y s t e m 2 4
P i l o t A i r S c r e w 2 4
Pilot Jet 24
Jet Needle 24
Needle 'E'-Clip Position 24
Optional Jet Needles 24
T h r o t t l e V a l v e ( S l i d e ) 2 4
Main Jet 25
Float Level Adjustment 25
W I R I N G H A R N E S S 2 6
260 LQ 26
W A S H I N G / S T O R A G E 2 7
W a s h i n g Yo u r M o t o r c y c l e 2 7
Motorcycle Storage 27
Removing a Motorcycle from Storage 27
Included Supplement:
ATK 125 Model
Specific Details

ATK 125 SUPPLEMENT
THIS IS A SUPPLEMENT TO THE ATK 125 / 250 I 260 OWNER'S MANUAL TO BE
USED EXCLUSIVELY FOR THE ATK 125. THIS SUPPLEMENT ONLY DISCUSSES
THE ITEMS THAT ARE DIFFERENT FROM THE 125 I 250 I 260 MANUAL. FOR ANY
INFORMATION NOT COVERED IN THIS SUPPLEMENT, PLEASE CONSULT THE
Engine Specifications
Engine Type
Displacement
Compression Ratio
Carburetion
Ignition Output
Spark Plug
Transmission
Starting System
Fuel Capacity
Fuel Requirement
Fuel/Oil Mixing Ratio
CyUnder Bore
Standard Piston Size
Stroke
Cylinder to Piston Skirt Clearance
Transmission Oil Capacity
Transmission Oil Weight
Motorcycle Specifications
Wheelbase
Rake /Trail
Seat Height
Ground Clearance
Weight (Wet, no fuel)
Front Tire
Rear Tire
Tire Pressure
Front Suspension Specifications
Type
Travel
External Adjusnnents
Standard Compression Setting
Standard Rebound Setting
Fork Springs
Oil Level
Optional Fork Springs
Liquid cooled, counterbalancer, exhaust controlled power valve,
two stroke single
124.9 cc
7.0:1
35 mm Mikuni TMX
lOOW
NGKBRIOEG
6 speed wide ratio
Kick
3.1gallon (I 1.7 liters)
90 + octane unleaded
32:1 -50:1
54mm
53.98 mm
54.5
mm
0.02 - 0.0035 mm (0.0008 - 0.0014 inches)
600 cc (6/10 qt)
Premium 80w gear oil
1461 mm (57.5 inches)
26°/4.I inches
876 mm (34.5 inches)
279
mm (11.0 inches)
227
lb .
80 / 100 - 21
100 / 100 - 18
15 psi front and rear
WP 40 mm Upside Down forks with internal cartridge system
241 mm (9.5 inches)
Compression and rebound
18 'clicks' from closed
14 'clicks' from closed
0.40 kg/mm
130mm
0.38, 0.42 kg/mm
Owner's Manual.

ATK 125 SUPPLEMENT
Rear Suspension Specifications
Type
Travel
External Adjustments
Standard Compression Setting
Standard Rebound Setting
Shock Spring
Standard Spring Preload
Optional Shock Springs
Brake Specifications
Front Brake
Front Rotor
Rear Brake
Rear Rotor
Brake Fluid
Optional Parts
Driveline Specifications
Final Drive Ratio
Optional Sprockets, Front
Optional Sprockets, Rear
Drive Chain
Transmission Ratios
Primary Drive
I st
2nd
3rd
4th
5th
6th
Kill Button:
WP piggyback damper with a 102 mm stroke
279
mm (11.0 inches)
Compression and rebound
3
5
5.6N/mm
15mm
5.9, 6. 0, 6.2 N/mm
Brembo dual piston
260 mm (10.4 inches) stainless steel
Brembo single piston ·
220
mm (8.8 inches) stainless steel
Golden Spectro supreme DOT4 (DOT 5.1 non-silicone specifications)
Solid rotors
14-50
13, 15, 16
40,42,44,46,48,52
D.l.D. 520 VX 120 o-ring, 112 links
63/19
30/ IO
29114
27117
25 / 19
23 /21
21 /22
3.316
3.000
2. 071
1.588
1.316
1. 095
0.955
The kill switch is attached to the throttle assembly. When the red lever at the bottom of the switch is moved
to the right, the engine is 'off' and will stop running. When the lever is moved to the left, the engine can be
turned 'on', and will continue running. This is a bit confusing because the smaJI pictures on the back plate
of the switch indicate that the switch works in the opposite manner (right - on, left -off). However, the
switch only works in the above described manner. Note: the button at the top of the switch has no function.
CarburetorSpecifications
Type
MikuniTMX
Size 35mm
Pilot Air Screw
1.5 turns out
Pilot Jet
17.5
Jet Needle 6ENU-54
'E' Clip Position 5th slot from bottom
Throttle Valve (Slide) 4.0
Main Jet
310