
B5-B7
ATC25DES
BIGREC

HOW TO USE THIS MANUAL
Sections 1 through 3 apply [0 the whole
ATe, white sections 4 through 18 describe
parts of the ATC, grouped according to
location,
Find the section you want on this page,
then turn to the table of contents on page 1
of that section.
Most sections start with an assembly or
system illustration, service information and
troubleshooting for the section. The subse-
quent pages give detailed procedures.
If you don't know what the source of the
trouble is. refer to section 19, Troubleshoot-
ing.
w
Z
to
Z
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a:
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CONTENTS
GENERAL INFORMATION
LUBRICATION
MAINTENANCE
FUEL SYSTEM
ENGINE REMOVAL/INSTALLATION
!rn INOER HEAO/V ALVES
CYLINOER/PISTON
CLUTCH/OIL PUMP/KICK STARTER
IGNITION SYSTEM
BATTERY/CHARGING SYSTEM
STARTER SYSTEM
LIGHTS/SWITCHES
WIRING OIAGRAMS
L-= ~============
TROUBLESHOOTING
INDEX

1. GENERAL INFORMATION
GENERAL SAF ET Y
SERVICE RU LES
MODEL IDENTIFICATION
SPECIFICATIONS
TORQUE VALU ES
TOOLS
CABLE & HARNESS ROUTING
NOISE EMISSION CONTROL SYSTEM
GENERAL SAFETY
l' f4W@i
1/ the engint' must be running to do som" work, make sure the
Ufeu is ... efl-~'entilared. Never run t he engine in a closed QUO.
The exhaust contains poi sonous carbon monoxide gas.
GW.!;!.l!wa
The bal/uy gtneralu hydrogen gas which can be highly ex-
plash-e. Do nOl smoke or aliait' flames or sparks near the bat-
tery, especially while charging It.
SERVICE RULES
,-,
,-,
' -2
' -3
' -5
' -9
,- l'
,- 17
"'"-"""' /s. ;X"","'''/) /lammable and is f'XpfosiI'f! under certain
conditions. Do not smoke or allow flames or sparks in )'our
work area.
The baltery electfolyu contains sui/uric acid. {',otect )' OU1
eyes, skin and clo/hing. In case 0/ contact, /lush ,horollghly
wilh water and call a doctor if electrol yte gelS in your eyes.
, . Use genuine HONDA or HONDA-recommended parts and lubricants or their equivalents. Parts.that don 't meet HONDA's
design specifications may cause damage to the ATC.
2. Use the special tools designed for this product to avoid damage and incorrect assembly.
3. Use only metric tools when servicing this ATC. Metric bolts, nuts, and screws are not interchangeable with English
fastener s.
4 . Install new gaskets, O-rings, cotter pins, lock plates, when reassembling.
5. When tightening bolts or nuts , begin with larger-diameter or inner bolts first. Then tighten to the specified torque diagonal-
ly in 1 - 5 steps, unless a particular sequence is specified.
6. Clean parts in non-flammable or high flash point solvent upon disassembly.
7. Lubricate any sliding surfaces before reassembly.
8. After reassembly, check all parts for proper installation and operation.
1-1

GENERAL INFORMATION
MODEL IDENTIFICATION
VEH ICLE IIDENTIFICATICIN
head's left side.
ENGINE SERIAL NUMBER
The engine serial number is stamped on the crankcase
lower right side.
1-2
The frame serial number is stamped on the steering head
right side.
CARBURETOR IDENTIFICATION
The carburetor identification number is on the carburetor
body left side.

SPECIFICATIONS
DIMENSIONS
FRAME
ENGINE
CARBURETOR
Overall length
Overall width
Overall height
Wheel base
Rear tread
Seat height
Foot peg h eight
Ground clearance
Dry weight
Type
Front suspension, travel
Rear suspension, travel
Rim size
Front tire size, pressure
Rear lire size, pressure
Front brake
Rear brake
Fuel capacity
Fuel reserve capacity
Caster
Trail
Front fork oil capacity
Type
Cylinder arrangement
Bore x stroke
Displacement
Compression ratio
Valve train
Maximum horsepower
Maximum torque
Oi l capacity
Lubrication system
Cylinder compression
Intake valve
Exhaust valve
Valve clearance
(Cold)
Engine dry weight
Type
Venturi dia.
Main jet
Primary jet
Starter fuel jet
Pi lo t screw opening
Jet needle
Float level
Idle speed
Front
Rear
Opens
Closes
Opens
Closes
Intake
Exhaust
GENERAL INFORMATION
1,887 mm 174.3 in)
1,137 mm ( 44.8 in)
1,038 mm (40.9 in)
1,237 mm \48.7 in)
840 mm (33.0 in)
705 mm 127.8 in)
267 mm (lO.S in)
165 mm (6 .5 in)
'85 : 184 kg (406 Ibl
A ft er '85: 186 kg (41 0 Ib)
Semi-doub le cradle
Te l escopic fork, 115 mm 1 4.5 in)
Swingarm, 110 mm (4.3 in)
9 in
9 in
25 x 12.00 - 9,0.15 kg / cm 2 (2.2 psi)
25 x 12.00-9 , 0.15 kg / cm 2 12.2 psi)
Cable operated leading shoe
Cable operated leading shoe
12 liters (3.2 US ga l, 2.6 Imp gal)
2.0 liters (0.53 US gal, 0.44 Imp gal)
19.5 °
o mm (0 in)
113+2.5 cc (3.8+0.08 oz)
Gasoline, air- coiled 4 -s troke
Single cy l inder inclined 20°
74.0 x 57 .3 mm 12 .91 x 2.26 in)
246 cc ( 15 .0 cu in)
9 1
Overhead camshaft chain drive
17.8 BH P!7000 rpm (18PS!7000 rpm)
1.9 kg-m / 6000 rpm
(1 3.7 ft - lb/ 6000 rpm)
2.5 l iter (2 .6 US qt, 2.2 Imp qtl after
disassembly
2.1 liter (2.2 US qt, 1.8 Imp qtl after draining
Forced pressure and wet sump
12 - 13 kg/ cm
2
( 170 - 185 psi)
8° BTDC
35° ABDC
40 ° BBDe
5° ATDC
0.08 mm (0.003 in)
0.08 mm (0.003 in)
46.3 kg ( 102 Ib )
Dual valve
27 mm n .06 in)
#130
#45
see page 4-'
2 turns out
4 DB - 2nd groove
18.5 mm (0.73 in)
1 ,400± 1 00 rpm
mm lift
1-3

GENERAL INFORMATION
DRIVE TRAIN Clutch Wet multi·plate, semi · automatic
Transm ission 5-speed constant mesh wi th reverse
Primary reduction 2.407 (65/27)
Gear rat io SL 4.083 (49/ 12)
,
2.389 (43/18)
II 1.609 (37/23)
"'
1.179 (33/28)
,v 0.906 (29/32)
Reverse 7.333 (34/12) (44/ 17 )
Final reduction 5.684 (19 / 13) (35 /9)
Gearshift pattern left foot operated return system,
Forward: N·$L·,·2 ·3-4
Reverse N-R
ELE CTRICAL Ignition C.D.I.
Ignition timing Init ial 13
0
BTDC at idle
Full advance 31
0
BTDe at 3,500 rpm
Alternator Capacity 200 W/ 5,OOO rpm
Battery 12V- 10 AH
Spark plug OA8ES-L (NGK)
X24ESR-U (NO)
Spark plug gap 0.6- 0.7 mm (0,024-0.028 in)
Headlight 12V SOW/BOW
Taillight 12V5Wx2
Neutral indicator 12V 3W
Reverse indicator 12V 3W
1-4

TORQUE VALUES
'85
ENGINE
Item
Cylinder head socket bolt
Cylinder head cap nut
Crankcase SH bolt
Gearshift return spring pin
Output gear case socket bolt
Output driven gear bearing
holder socket bolt
Output gear bearing outer lock nut
Output driven gear bearing outer lock
not
Output gear bearing inner lock nut
Kick starter stoppe r plate socket bolt
Flywheel bolt
Pulse generator screw
Right crankcase cover SH bolt
Left crankcase cover SH bolt
Oil separator plate SH bolt
Manual clutch lock n ut
Clutch lifter cap bolt
Centrifugal clutch lock nut
Cylinder base SH bolt
Cam sprocket bolt
Cylinder head cover SH bolt
Valve adjusting lock nut
Cam chain holder socket bolt
Spark plug
Intake manifold band screw
Oil filter cover SH bolt
Neutral/Reverse switch
Starter clutch socket bolt
Cam chain tensioner lifter SH bolt
Alternator stator SH bolt
Breather plate socket bolt
Clutch adjusting screw lock nut
Cam chain tensioner lifter sealing bolt
Q'ty
Thread Size
(mm)
3 B , 1 .25
•
lax 1 .25
,. 6 , 1 .0
1 B , 1 .25
3 8 )( 1.25
3 8 )( 1.25
1 64)( ' .5
1 60 x 1.5
1 28)( '.0
2 6 x 1.0
1 12 )( 1.25
2 5)( 0.8
12 6, 1.0
11 6 x 1.0
2 6 x 1.0
1 18 x 1 .0
•
6 x 1.0
1 20 x 1.0
2 6, 1 .0
2 7 , 1 .0
7 6,1 .0
2 6 x 0.75
1 6, 1.0
3 7, 1.0
1 12xl.25
1 5 x 0.8
3 6 x 1.0
2 lOx 1.25
6 8 x 1.25
2 6 x 1.0
3 6 x 1.0
1 6 x 1.0
1 8 x 1.25
1 6 x 1.0
GENERAL INFORMATION
Torque
N'm kg -m ft -Ib
22- 28 2.2-2.8 16 - 20
35-45 3.5 - 4.5 25 - 33
8- 12 0.8 - 1.2 6- 9
18 - 25 1.8-2 .5 13- 18
20 - 25 2.0 - 2.5 , 5- 18
20 - 25 2.0 - 2.5 15 - 18
90 - 110 9.0-11 .0 65-80
90 - 1 10 9.0 - 11 .0 65 - 80
70 - 80 7.0-8.0 51 - 58
10-14 1.0-1.4 7- 10
100 - 120 10.0-12.0 72-87
8-12 0.8 - 1.2 6- 9
8- 12 0.8 - 1.2 6- 9
8- 12 0.8-1.2 6- 9
8- 12 0.8-1.2 6- 9
100 - 120 10 - 12 72 - 87
10 - 14 1.0-1.4 7- 10
110 - 130 11.0 -1 3.0 80 - 94
8- 12 0.8 - 1 .2 6- 9
17 - 23 1.7 - 2.3 12 - 17
8- 12 0 .8 - 1.2 6- 9
15 - 18 1.5 - 1.8 11 - 13
8- 12 0.8 - 1.2 6- 9
8- 12 0 .8 - 1.2 6- 9
15 - 20 1.5 - 2.0 11-15
3- 5 0.3 - 0.5 2-
•
8- 12 0.8-1.2 6- 9
11 - 15 1.1 - 1.5 8- 11
18 - 25 1.8-2.5 13 - 18
8- 12 0.8 - 1.2 6- 9
8- 12 0.8-1.2 6- 9
10- 14 1 .0 -1 .4 7- 10
19 -25 1.9-2 .5 14 - 18
8 - 12 0.8-12 6- 9
1-5

GENERAL INFORMATION
FRAME
Item Q'ty
Thread Size
Torque
(mm)
N·m kg-m ft-Ib
Handlebar upper holder bolt 4 8 , 1 .25 18- 30 , .8-3.0 13 - 22
Handlebar upper holder nut 2 10 x , .25 40 - 50 4.0-5.0 29 - 36
Fork bridge bolt 2 12 x 1 .25 50 - 70 5.0- 7.0 36 - 51
Steering stem nut 1 24 x 1.0 70 - 90 7.0 - 9.0 51 - 65
Steering bearing adjustment nut
Unitisi) 1 24 x 1.0 25-35 2.5 - 3.5 18 - 25
(Final) 7-8 0.7-0.8 5- 6
Wheel nut 12 10 x 1. 25 50 - 60 5.0-6.0 36 - 43
Front axle 1 14 x 1.5 70-110 7.0-11.0 51 - 80
Rear axle nut 2 20 x '.5 80- 1 20 8.0 - 12.0 58-87
Rear brake panel nut 4 10 x 1.25 50 - 60 5.0 - 6.0 36-43
Rear shock absorber mount bolt 2 10x1. 25 50-60 5.0-6.0 36 - 43
Front fork mount bolt 4 10x1.25 50-.60 5.0-6.0 36-43
Swingarm right pivot bolt 1 30 x 1.5 16-20 1.6-2.0 12-15
Swingarm left pivot bolt 1 30 x 1.5 100 - 130 10,0 - 13.0 72-94
Swingarm pivot lock nUl 1 30 x 1.5 100 - 130 10 .0 - 13.0 72 - 94
Final gear case mount bolt 4 10xl.25 50-60 5.0-6.0 36-43
4 8 x 1.25 28 - 35 2.8-3.5 20 - 25
Rear left bearing housing bolt 4 8 x 1.25 28-35 2.8 - 3.5 20 - 25
Engine hanger bolt 9 10xl.25 45 - 65 4.5 - 6.5 33-47
Gearshift pedal bolt 1 6 x 1.0 10-14 1.0 - 1.4 7- 10
Foot peg bracket bolt 4 10xl.25 40-50 4.0-5.0 29-36
Intake manifold bolt 2 6 x 1.0 6- 9 0.6-0.9 5- 7
Muffler clamp bolt 2 8 x 1.25 18 -28 1.8-2.8 13-20
Front fork socket bolt 2 8 x 1.25 18-25 1 .8 - 2.5 13 - 18
Rear shock absorber rod lock nut 1 12 x 1.25 38-60 3.8 - 6.0 27 - 43
Final gear case cover bolt 2 10 x 1.25 45 - 50 4.5 - 5.0 25 - 36
6 8 xl.25 23 - 28 2.3 - 2.8 17 - 20
Pinion joint nul 1 16 x 1 .5 100 - 120 10.0-12.0 72 - 87
Pinion bearing outer race lock nut 1 60 x 1 .5 90-110 9.0 - 11.0 65 - 80
Torque specifications listed above are for the most impor tant tightening points. If a torque specification is not listed, follow the
standards given below.
STANDARD TORQUE VALUES
Item Torque N'm (kg-m, ft-Ib) Item Torque N'm Ikg -m, ft-Ib\
5 mm bolt, nut 4.5-6 (0.45 - 0.6, 3- 4) 5 mm screw 3.5 - 5 (0.35 - 0.5,2 - 4)
6 mm bolt, nut 8- 12 (0.8-1.2, 6-9) 6 mm screw, SH bolt 7- 11 (0.7 - 1.1,5 - 8)
8 mm bolt, nut 18 25 (1.8-2.5, 13 - 18) 6 mm flange bolt, nut 10 - 14 (1.0 - 1.4, 7- 10)
10 mm bolt, nut 30 - 40 (3.0-4.0, 22-29) 8 mm flange bolt, nut 24-30 (2.4 - 3.0,17 - 221
1 2 mm bolt, nut 50-60 (5.0-6.0, 36 - 43) 10 mm flange bolt, nut 35 - 45 (3.5-4.5, 25-33)
1-6

GENERAL INFORMATION
AFTER '85:
ENGINE
Item G'ty
Thread Size Torque
(mm)
N'm kg·m ft · lb
Cylinder head socket bolt 3 8 x 1.25 22-28 2.2- 2.8 16- 20
Cylinder head cap nut 4 lOx 1.25 35-45 3.5-4.5 25-33
Crankcase SH bolt 14 6 x 1.0 8-12 0.8-1.2 6-9
Gearshift return spring pin bolt 1 8 x 1.25 18-25 1.8-2.5 13- 18
Output gear case boh
3 8)( 1.25 30-34 3.0 3.4 n 25
Output driven gear bearing
3 8)( 1. 25 20 -25 2.0-2.5 14- 18
holder socket bolt
Output gear bearing outer lock nut 1 64)( 1.5 90- 110 9.0-11.0 65- 80
Output driven gear bearing outer
1 60)(1.5 90-110 9.0 - 11.0 65- 80
lock nut
Output gear bearing inner lock nut 1 28 x 1.0 70-80 7.0-8.0 51 - 58
Kic k starter stopper plate socket bolt 2 6x1 .0 10-14 1.0- 1.4 7- 10
Flywheel bolt 1 12)(1.25 100-120 10.0- 12.0 72- 87
Pulse generator screw 2 5)( 0.8 5-7 0.5- 0.7 4- 5
Right crankcase cover SH bolt 12 6 x 1.0 8-12 0.8- 1.2 6- 9
Left crankcase cover SH bolt 11 6 x 1.0 8-12 0.8- 1.2 6- 9
Oil separator plate SH bolt 2 6 x 1.0 8- 12 0.8-1.2 6- 9
Manual clutch lock nut 1 18)( 1.0 100-120 10.0- 12.0 72- 87
Outch lifter bolt 4 6 x 1.0 10-14 1.0- 1.4 7-10
Centrifugal clutch lock nut 1 20 x 1.0 110-130 11.0- 13.0 80 - 94
Cylinder base SH bolt 2 6 x 1.0 8-12 0.8- 1.2 6- 9
Cam sprocket bolt 2 7 x 1.0 17-23 1.7 - 2.3 12- 17
Cylinder head cover SH bolt 7 6 x 1.0 8-12 0.8- 1.2 6- 9
Valve adjusting lock nut 2 6 x 0.75 15-18 1. 5- 1.8 11 - 13
Cam chain holder socket bolt 1 6 x 1.0 1 0-14 1.0 - 1.4 7-10
Oil pipe bolt 3 7 x 1.0 10- 14 1.0- 1.4 7- 10
Spark plug 1 12xl .25 15- 20 1.5- 2.0 11 - 14
Intake pipe band screw 1 5 x 0 .8 3-5 0.3- 0.5 2-4
Oil filter cover SH bolt 3 6 x 1.0 8-12 0.8- 1.2 6- 9
Neutral/ Reverse switch 2 10 x 1.25 11-15 1.1 - 1.5 8- 11
Starter clutch torx bolt 6 8 x 1.25 20-25 2.0-2 .5 14- 18
Cam chain tensioner lifter SH bolt 2 6 x 1.0 8-12 0.8- 1.2 6- 9
Alternator stator SH bolt 3 6 x 1.0 8-12 0.8- 1.2 6- 9
Breather plate socket bolt 1 6 x 1.0 10-14 1.0- 1.4 7- 10
Clutch adjusting screw lock nut 1 8 x 1.25 18 25 1.8- 2.5 13- 18
Cam chain tensioner lifter sealing bolt 1 6 x 1.0 8 12 0 .8 1.2 6 9
Engine oil drain plug 1 12 x 1.5 20-30 2.0-3.0 14 - 22
Intake p ipe bolt
2 6 x 1 .0 10- 14 1.0- 1.4 7- 10
Gear case drain bolt 1 8 x 1.25 10-14 1.0- 1.4 7- 10
Gear case filler cap
1 30 x 1.5 10-14 1.0-1.4 7- 10
1-7

GEN ERAL INFORMATION
FRAME
Item G'ty
Thread Size Torque
(mm)
N·m kg-m ft·lb
Handlebar upper holder bolt 4 a x 1.25 18-30 1.8-3.0 13-22
Handlebar lower holder nut 2 lOx 1.25 40-50 4.0-5.0 29-36
Fork bridge bolt 2 12 x 1.25 50-70 5.0- 7.0 36 - 51
Steering stem nut 1 24 x 1.0 70-90 7.0-9.0 51 - 65
Steering bearing adjustment nut
(In i tial) 1 24)( 1.0 25-35 2.5- 3.5 18-25
(F inal) 7 -8 0.7- 0.8 5- 6
Wheel nut 12 10xl.25 60-70 6.0-7.0 43 -51
Front axle 1 14 )( 1.5 70-110 7.0-11.0 51-80
Rear axle nut 2 18xl.5 80-140 8.0-14.0 58-101
Rear brake panel nut 4 10)( 1.25 SO-60 5.0-6.0 36-43
Rear shock absorber mount bolt 2 10 x 1.25 50-60 5.0- 6.0 36-43
Front fork pi nch boh 4 10 x 1.25 50-60 5.0- 6.0 36-43
Swingarm right pivot bolt 1 30 x 1.5 16-20 1.6-2.0 12- 14
Sw ingarm left pivot bolt 1 30 x 1.5 100- 130 10.0- 13.0 72- 94
Swingarm pivot lock nut 1 30 x 1.5 100~130 10.0- 13.0 72-94
Final gear case mount bolt 4 10xl .25 50-60 5.0- 6.0 36-43
4 8 x 12.5 30-36 3.0 - 3.6 22-26
Left rear bearing housi ng bolt 4 8 x 1.25 30-36 3.0-3.6 22-26
Engine hanger bolt lOmm 9 10xl .25 45-65 4.5- 6.5 33-47
8mm 2 8 x 1.25 24-30 2.4- 3.0 17-22
Gearshih pedal bolt 1 6 x 1.0 14-18 1.4- 1.8 10-13
Foot peg bracket bolt 4 10 x 1.25 40 -50 4.0- 5.0 29- 36
Intake manifold bolt 2 6 x 1.0 10-14 1.0- 1.4 7- 10
Muffler clamp bolt 2 8 x 1.25 18- 28 1.8-2.8 13- 20
Front fork socket bolt 2 8 x 1.25 15-25 1.5- 2.5 11 - 18
Aear shock absorber rod lock nut 1 12 x 1.25 38-60 3.8- 6.0 27- 43
Final gear case cover bolt 10 mm 2 10 x 1.25 45 50 4.5 5.0 33 - 36
Smm 6 8 x 1.25 23 28 2.3 2.S 17 20
Pinion joint nut 1 16 x 1.5 100-120 10.0- 12.0 72- 87
Pinion bearing outer race lock nut 1 60 x 1.5 90-110 9.0- 11 .0 65 -80
Front axle holder nut 4 6 x 1.0 10- 14 1.0- 1.4 7- 10
..
Torque specifications listed above are for the most Important tightening pOints. If a torque speCification IS not hsted, follow the
standards given below.
STANDARD TOROUE VALUES
Item Torque N·m (kg-m, ft·lb) hem Torque N·m (kg-m, ft·lb)
5 mm bolt, nut 4.5- 6 (0.45-0.6, 3-4) 5 mm screw 3.5 - 5 (0.35- 0.5,2- 4)
6 mm bolt, nut 8- 12 (0.8- 1.2, 6- 9) 6 mm screw, SH bolt 7- 11 (0.7- 1.1,5-8)
8 mm bolt, nut 18- 25 (1.8- 2.5, 13- 18) 6 mm flange bolt, nut 10- 14 (1.0-1.4, 7-10)
10 mm bolt, nut 30 40 (3.0 4.0,22 29) 8 mm flange bolt, nut 24 - 30 (2.4- 3.0, 17 -22)
12 mm boll, nut 50 6015.0 6.0,36 431 10 mm flange bolt, nut 35 45 (3.5-4.5,25-33)
1-8
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Honda ATC 250ES Service Manual 1985-1987
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Description
The Honda ATC 250ES Service Manual from 1985 to 1987 is an essential resource for anyone involved in the repair and maintenance of Honda ATC 250ES vehicles. This comprehensive manual provides detailed technical information, step-by-step procedures, and illustrations to assist both professional mechanics and DIY enthusiasts in servicing, repairing, and troubleshooting the ATC 250ES. Whether you are performing routine maintenance or tackling more complex repairs, this manual is designed to be a valuable tool in ensuring the proper functioning of the vehicle.