Arctic Cat 2018 ZR 200 User manual

1
2018 ZR 200 Service Manual
Table of Contents
General Information/Foreword.......................................... 2
Snowmobile Identification ............................................. 2
Recommended Gasoline and Oil.................................. 3
Break-In Procedure ...................................................... 3
Genuine Parts............................................................... 3
Preparation for Storage ................................................ 3
Preparation After Storage ............................................. 4
Torque Conversions (ft-lb/N-m)..................................... 4
Torque Specifications.................................................... 5
Engine Torque Diagram ................................................ 6
Engine Specifications ................................................... 7
Carburetor Specifications ............................................. 7
Track Specifications ...................................................... 7
Front/Rear Shock Spring .............................................. 7
Rear Suspension Spring............................................... 7
Front Shock Absorber................................................... 7
Rear Shock Absorber ................................................... 7
Engine................................................................................. 8
Removing...................................................................... 8
Disassembling .............................................................. 9
Servicing Components ............................................... 13
Assembling ................................................................. 19
Installing ..................................................................... 23
Changing Oil............................................................... 26
Recoil Starter.............................................................. 26
Troubleshooting Engine .............................................. 28
Fuel System...................................................................... 29
In-Line Fuel Filter........................................................ 29
Carburetor................................................................... 29
Throttle Cable ............................................................. 33
Troubleshooting Fuel System ..................................... 34
Electrical System ............................................................. 35
Transistorized Ignition System.................................... 35
Testing Ignition Switches ............................................ 35
Testing Electrical Resistances .................................... 36
Testing RPS Switch .................................................... 37
Testing Idle Switch.......................................................37
Testing Handlebar Warmer Elements..........................37
Testing Handlebar Warmer Switch ..............................37
Testing Headlight Switch .............................................38
Testing Key Switch ......................................................38
Drive Train/Track/Brake Systems ....................................39
Drive Belt.....................................................................39
Drive Clutch.................................................................39
Driven Clutch...............................................................41
Drive Clutch/Driven Clutch ..........................................42
Dropcase.....................................................................42
Track............................................................................44
Brake System ..............................................................46
Troubleshooting Track..................................................49
Rear Suspension ..............................................................50
Removing Skid Frame.................................................50
End Cap ......................................................................50
Wear Strip ...................................................................51
Rear Suspension Arm/Rear Springs ...........................51
Rear Idler Wheels and Axle.........................................52
Slide Rail .....................................................................53
Installing Skid Frame ...................................................54
Steering and Body............................................................55
Steering Post...............................................................55
Ski ...............................................................................57
Ski Wear Bar ...............................................................57
Tie Rods......................................................................57
Spindle ........................................................................58
Ski Alignment ..............................................................59
Front Suspension A-Arms ...........................................60
Belly Pan .....................................................................61
Seat Assembly ............................................................62
Gas Tank/Fuel Pump Assembly ..................................63
Headlight Assembly.....................................................64
Wiring Diagram .................................................................65

2
General Information/
Foreword
NOTE: Whenever a part is worn excessively,
cracked, or damaged in any way, replacement is nec-
essary.
NOTE: Some illustrations and photographs used in
this manual are used for clarity purposes only and are
not designed to depict actual conditions.
This Arctic Cat Service Manual contains service and
maintenance information for the 2018 Arctic Cat ZR 200
Snowmobile. The manual is designed to aid service per-
sonnel in service-oriented applications.
This manual is divided into sections. The sections cover
specific snowmobile components or systems and, in
addition to the standard service procedures, includes
assembling, disassembling, and inspecting instructions.
When using this manual as a guide, the technician should
use discretion as to how much disassembly is needed to
correct any given condition.
This service manual is designed primarily for use by an
Arctic Cat CatMaster Basic Level technician. The proce-
dures found in this manual are of varying difficulty, and
certain service procedures in this manual require one or
more special tools to be completed. The technician
should use sound judgment when determining which pro-
cedures can be completed based on their skill level and
access to appropriate special tools.
All Arctic Cat publications and snowmobile decals dis-
play the words Warning, Caution, and Note to emphasize
important information. The symbol ! WARNING
identifies personal safety-related information. Be sure to
follow the directive because it deals with the possibility
of severe personal injury or even death. A CAUTION
identifies unsafe practices which may result in snowmo-
bile-related damage. Follow the directive because it deals
with the possibility of damaging part or parts of the
snowmobile. The symbol  NOTE: identifies supple-
mentary information worthy of particular attention.
At the time of publication, all information, photographs,
and illustrations were technically correct. Some photo-
graphs and illustrations used in this manual are used for
clarity purposes only and are not designed to depict
actual conditions. Because Arctic Cat Inc. constantly
refines and improves its products, no retroactive obliga-
tion is incurred.
All materials and specifications are subject to change
without notice.
Keep this manual accessible in the shop area for refer-
ence.
Product Service and Warranty Department
Arctic Cat Inc.
© 2017 Arctic Cat Inc. Effective November 2017
®™ Trademarks of Arctic Cat Inc., Thief River Falls, MN
SPECIAL TOOLS
A number of special tools must be available to the techni-
cian when servicing this snowmobile.
NOTE: Special tools are available from the Arctic
Cat Service Parts Department.
Snowmobile Identification
The Arctic Cat Snowmobile has two important identifica-
tion numbers. The Vehicle Identification Number (VIN)
is stamped into the tunnel near the right-side footrest.
The Engine Serial Number (ESN) is on a decal placed on
the front side of the recoil cover.
0726-200
0744-926
These numbers are required to complete warranty claims
properly. No warranty will be allowed by Arctic Cat Inc.
if the engine serial number or VIN is removed or muti-
lated in any way.
Description p/n
V Blocks 0644-535
Surface Plate 0644-016
Ball Hone 0644-290
Shock Spring Removal Tool 0644-057
Fluke Model 88 Multimeter 0644-559
Fuel Hose Clamp Tool 0644-545
Clutch Alignment Bar Tool 0644-624
Engine Alignment Tool 0644-643
Drive Clutch Holder Tool 0644-644
Hayes Brake Bleed Kit 3602-074

3
Recommended Gasoline
and Oil
RECOMMENDED GASOLINE
The recommended gasoline to use in these snowmobiles
is 87 octane regular unleaded.
NOTE: In many areas, oxygenates are added to the
gasoline. Oxygenated gasolines containing up to 10%
ethanol are acceptable gasolines; however, whenever
using oxygenated gasolines, the carburetor main jet
must be one size larger than the main jet required for
regular unleaded gasoline. For example, if a 77.5 main
jet is recommended for regular unleaded gasoline, an
80 main jet must be installed if using an oxygenated
gasoline.
When using ethanol-blended gasoline, adding a gasoline
antifreeze is not necessary since ethanol will prevent the
accumulation of moisture in the fuel system.
RECOMMENDED OIL
The recommended oil to use in the engine is 0W-40 Syn-
thetic oil. See the viscosity chart for details.
OILCHARTJ
Break-In Procedure
The Arctic Cat engine requires a short break-in period
(approximately 10 operating hours) before being sub-
jected to heavy load conditions or full-throttle operation.
Strict adherence to the break-in procedure will contribute
to optimum performance and longevity of the engine.
During break-in, a maximum of 1/2 throttle is recom-
mended; however, brief full-throttle accelerations and
variations in driving speeds contribute to good engine
break-in. After the 10-hour break-in period, the snowmo-
bile may be taken to an authorized Arctic Cat Snowmo-
bile dealer for a checkup and oil change at the discretion
and expense of the snowmobile owner.
Genuine Parts
When replacement of parts is necessary, use only genuine
Arctic Cat parts. They are precision-made to ensure high
quality and correct fit.
Preparation for Storage
Prior to storing the snowmobile, it is extremely important
that it be properly serviced to prevent corrosion and com-
ponent deterioration. Arctic Cat recommends the follow-
ing procedure to prepare the snowmobile for storage.
1. Clean the seat cushion with vinyl protectant and a
damp cloth.
2. Clean the snowmobile thoroughly by hosing dirt, oil,
grass, and other foreign matter from the undercar-
riage, tunnel, hood, and belly pan. Allow the snow-
mobile to dry thoroughly. DO NOT get water into
any part of the engine.
3. Drain all gas from the gas tank. Drain the gasoline
from the carburetor by loosening the drain screw on
the carburetor float chamber.
4. Plug the muffler outlet with a clean cloth.
5. With the ignition key in the OFF position:
A. Disconnect the spark plug cap from the spark plug;
then remove the spark plug.
B. Pour 10 ml (approximately two teaspoons) of petro-
leum-based oil into the spark plug hole; then pull the
recoil starter handle slowly about five times.
C. Install the spark plug and connect the spark plug cap.
6. Change the oil.
7. Tighten all screws, nuts, and cap screws securely.
8. Make sure all rivets holding components together are
tight. Replace all loose rivets.
9. Clean and polish the hood, console, and chassis with
Cat Cleaner (p/n 4639-371). DO NOT USE SOL-
VENTS. THE PROPELLANT WILL DAMAGE
THE FINISH.
CAUTION
Do not use white gas or gasolines containing methanol.
Only Arctic Cat-approved gasoline additives should be
used.
CAUTION
Any oil used in place of the recommended oil may
cause serious engine damage.
CAUTION
Never crank the engine over without grounding the
spark plug. Damage to the transistorized ignition may
result.

4
10. If possible, store the snowmobile indoors. Raise the
rear of the snowmobile off the floor and block up the
rear end. Cover the snowmobile with a snowmobile
cover to protect it from dirt and dust.
11. If the snowmobile must be stored outdoors, block the
entire snowmobile off the ground and cover it with a
snowmobile cover to protect it from dirt, dust, and
rain.
Preparation After Storage
Taking the snowmobile out of storage and correctly pre-
paring it for operation will ensure many miles and hours
of trouble-free snowmobiling. Arctic Cat recommends
the following procedure to prepare the snowmobile:
1. Clean the snowmobile thoroughly. Polish the exterior
of the snowmobile using Cat Cleaner.
2. Clean the engine cooling fins and the recoil starter
vents. Remove the cloth from the muffler.
3. Check all control wires and cables for signs of wear
or fraying. Replace if necessary. Use cable ties or
tape to route wires and cables away from hot or rotat-
ing parts.
4. Check brake-lever travel distance, all controls, ski
alignment, track tension, track alignment, brake
band, and ski wear bars; adjust or replace as neces-
sary.
5. Examine the in-line fuel filter and clean or replace if
necessary.
6. Fill the gas tank.
7. Clean the seat cushion with the vinyl protectant.
8. Check the spark plug (clean, gap, and/or replace as
necessary); then start the engine and ensure proper
carburetor adjustments.
Torque Conversions
(ft-lb/N-m)
CAUTION
Avoid using a plastic cover as moisture will collect on
the snowmobile causing corrosion.
ft-lb N-m ft-lb N-m ft-lb N-m ft-lb N-m
11.4 26 35.4 51 69.4 76 103.4
22.7 27 36.7 52 70.7 77 104.7
34.1 28 38.1 53 72.1 78 106.1
45.4 29 39.4 54 73.4 79 107.4
56.8 30 40.8 55 74.8 80 108.8
68.2 31 42.2 56 76.2 81 110.2
79.5 32 43.5 57 77.5 82 111.5
810.9 33 44.9 58 78.9 83 112.9
912.2 34 46.2 59 80.2 84 114.2
10 13.6 35 47.6 60 81.6 85 115.6
11 15 36 49 61 83 86 117
12 16.3 37 50.3 62 84.3 87 118.3
13 17.7 38 51.7 63 85.7 88 119.7
14 19 39 53 64 87 89 121
15 20.4 40 54.4 65 88.4 90 122.4
16 21.8 41 55.8 66 89.8 91 123.8
17 23.1 42 57.1 67 91.1 92 125.1
18 24.5 43 58.5 68 92.5 93 126.5
19 25.8 44 59.8 69 93.8 94 127.8
20 27.2 45 61.2 70 95.2 95 129.2
21 28.6 46 62.6 71 96.6 96 130.6
22 29.9 47 63.9 72 97.9 97 131.9
23 31.3 48 65.3 73 99.3 98 133.3
24 32.6 49 66.6 74 100.6 99 134.6
25 34 50 68 75 102 100 136

5
Torque Specifications
NOTE: Torque specifications have the following tol-
erances:
* w/Blue Loctite #243
Torque (ft-lb) Tolerance
0-15 ±20%
16-39 ±15%
40+ ±10%
Item Secured to Torque
ft-lb
DRIVE SYSTEM
Drive Clutch Engine 20
Driven Clutch Driven Shaft 40
Brake Bracket Bearing Holder Chassis 60 in.-lb
Drop Case Sprocket Driveshaft 16
Drop Case Chassis 96 in.-lb
Torque Bumper Bracket Chassis 16
Brake Caliper* Chassis 80 in.-lb
Brake Disc* Brake Hub 48 in.-lb
Brake Manifold Steering Support 72 in.-lb
Brake Disc* Driveshaft 16
MC Mount Master Cylinder 30 in.-lb
STEERING/FRONT SUSPENSION/CHASSIS
Ski Spindle 16
Ski Wear Bar 50 in.-lb
Ski Ski Handle 50 in.-lb
Steering Post* Chassis 96 in.-lb
Steering Tie Rod* Steering Post 20
Tie Rod* Spindle Arm 15
Steering Support Spar 96 in.-lb
Steering Support Upper Console 96 in.-lb
A-Arm Chassis 30
A-Arm Spindle 20
Shock Absorber Spindle 16
Shock Absorber Chassis 16
REAR SUSPENSION
Rail* Crossbrace Axle 20
Crossbrace Axle (Shock)* Rail 20
Support Bracket Rail 20
Support Bracket Front Arm 20
Rear Axle Housing* Rail 20
Rear Wheels Rear Axle Housing 34
Track Adjuster Rear Axle Housing 96 in.-lb
Limiter Strap Limiter Strap 40 in.-lb
End Cap Rail 45 in.-lb
Wear Strip Rail 50 in.-lb

6
Engine Torque Diagram
NOTE: Before engine assembly, ensure all threaded areas are clean to ensure an accurate torque value is
achieved.
200-ENG-18-1
= Torque control required
= Apply Loctite
= Lubricate with Arctic Cat 4-Stroke Engine Oil
= Lubricate with Arctic Cat All-Temp Grease

7
Engine Specifications Carburetor Specifications
Track Specifications
Front/Rear Shock Spring
* Optional Heavier Spring
Rear Suspension Spring
* Optional Heavier Spring
Front Shock Absorber
Rear Shock Absorber
Engine Model Number 7DHJ
Displacement 192 cc
No. of Cylinders 1
Bore x Stroke 70 x 50 mm
Compression Ratio 8.4:1
Cooling System Air
Spark Plug (NGK) BPR4ES
Spark Plug Gap 0.028-0.031"
Piston Skirt/Cylinder Clearance 0.0012-0.0018"
Piston Pin Diameter 0.6297-0.6299"
Piston Pin Bore Diameter (max) 0.6300"
Piston Pin/Connecting Rod Small End Clearance 0.008-0.024"
Piston Ring End Gap (1st/2nd)
(oil)
0.008-0.016"
0.008-0.028"
Piston Ring/Groove Clearance (1st)
(2nd)
0.0016-0.0031"
0.0008-0.0024"
Piston Ring Thickness (1st/2nd)
(oil)
0.059"
0.098”
Piston Diameter (10 mm from skirt edge) (min) 2.752"
Cylinder/Head Distortion (max) 0.004"
Connecting Rod Small End Bore Inside Diameter 0.6302-0.6307"
Connecting Rod Big End Inside Diameter 1.1024-1.1030"
Connecting Rod Big End Side Clearance 0.008-0.024"
Cam Lobe Height 1.050-1.059"
Crank Pin Diameter (min) 1.1011-1.1017"
Crank Pin/Connecting Rod Clearance 0.0006-0.0018"
Crankshaft Rod Journal (Out-of-Round/Taper) 0.004"
Crankshaft Runout (t.i.r.) 0.0016"
Valve Guide Inside Diameter (max) 0.22"
Valve Guide/Stem Clearance (max) (Int)
(Exh)
0.0016-0.0024"
0.0024-0.0031"
Valve Face Width (min) 0.028"
Valve Face Runout (max) 0.0012"
Valve Clearance —Cold (59°-77° F) (Int/Exh) 0.004"
Valve Seat Contact Width (min) (Int/Exh) 0.067"
Valve Stem Diameter (min) (Int/Exh) 0.022"
Valve Stem Runout (max) 0.0004"
Valve Spring Free Length (max) 1.245"
Camshaft End Running Surface (max) 0.592”
Camshaft End Play (max) 0.002”
Vibration —Hand/Arm 3.8 m/s
Vibration —Seat < 0.5 m/s
Main Jet Pilot Jet Idle Fuel Adjuster Screw
(Turns Out) Float Height
100 37.5 1 0.63"
Length Width Lug Height Tension @ 20
lb
93" 10" 1.00" 2"
Free Length Wire Diameter Rate LB/Inch # of Coils
6.97” 0.235” 85 9.58
6.75”* 0.243”* 85* 8.06*
Wire
Diameter Angle #of Coils
Coil
Width Length Length
0.375" 0° 4.50 2.43" 6.16" 4.57"
0.406"* 6°* 4.48* 2.45"* 6.03"* 4.57"*
Collapsed
Length
Extended
Length Stroke Piston Depth
7.78” 9.49” 1.71” N/A
Collapsed
Length
Extended
Length Stroke Piston Depth
6.50” 8.60” 2.1” N/A

8
Engine
This engine section has been organized into sub-sections
showing a progression for the complete servicing of the
Arctic Cat 200 cc engine. For consistency purposes, this
section shows a complete and thorough progression;
however, for efficiency it may be preferable to remove
and disassemble only those components needing to be
addressed and to service only those components. Also,
some components may vary. The technician should use
discretion and sound judgment.
Removing
1. Remove the screws securing the air cleaner cover to
the air cleaner case and account for the filter and
retaining plate.
ZR-143
2. Remove the flanged nuts securing the air cleaner
assembly to the carburetor and engine. Account for
the plate.
ZR-144
3. Remove the air cleaner case from the carburetor and
engine. Account for the gasket.
4. Remove the nut (A) and screw (B) securing the
choke cable to the carburetor; then remove the fuel
hose (C) from the carburetor. Remove the carburetor
from the engine.
ZR-145
5. Remove the two cap screws and lock nuts securing
the upper steering post bearings and retainers; then
remove the retainers and bearings.
ONS-025
6. Remove the cap screws, washers, and lock nuts
securing the tie rods to the steering post; then remove
the cap screws and lock nuts securing the steering
post to the chassis. Account for a washer, ground
wire, bearings, and the retainer.
ONS-026
NOTE: Use an additional wrench to keep the tie rod
end shaft from turning while removing the tie rod
lock nut.
7. Remove the steering post from the engine compart-
ment.
8. Cut the cable tie; then disconnect the coil and two
magneto wires at the front of the engine. Route them
out of the way.

9
ZR-161
9. Remove the screws securing the clutch guard; then
remove the guard.
ZR-148
10. While pulling up on the drive belt between the
clutches, rotate the driven clutch to help the driven
clutch open.
ZR-126
11. Remove the drive belt by pulling it up and over the
sheave.
12. Install the drive clutch retention tool over the drive
clutch sheaves; then remove the cap screw and
washer securing the drive clutch to the crankshaft.
Account for a spacer on the crankshaft.
ZR-125
13. Using a flat-blade screwdriver, press the tabs on the
lock washer covering the nuts securing the muffler to
the engine. Remove the nuts and springs securing the
muffler. Remove the muffler.
ZR-162
14. Pull the recoil starter rope out for enough to tie a
slip-knot in the starter rope below the steering sup-
port and allow the rope to slowly retract against the
recoil starter.
15. Remove the knot at the handle and remove the han-
dle; then thread the rope through the bushing in the
console.
16. Using a flat-blade screwdriver, remove the four belly
pan plugs covering the engine mounting cap screws;
then remove the cap screws and lock nuts.
NOTE: The front center plug is to access the oil
drain plug.
17. Remove the engine from the engine compartment.
Disassembling
1. Remove the oil drain plug and drain the oil; then
install the oil plug and tighten securely.

10
IO063
2. Remove the spring and hose from the governor arm.
3. Remove the throttle cable and retaining bracket from
the engine; then remove the governor arm rod from
the bracket.
ONS-039
4. Loosen the governor arm cap screw and remove the
arm; then disconnect the rod from the carburetor.
IO067A
5. Slide the intake tube and carburetor off the mounting
studs. Account for three gaskets and an insulator
block.
IO068
NOTE: If the cylinder head will be replaced, the
carburetor studs may be removed by tightening the
two nuts against each other; then using a wrench on
the inside nut, remove the stud.
6. Remove the recoil starter/fan housing assembly.
7. Remove the spark plug wire from the spark plug and
remove the spark plug; then remove the cap screws
securing the ignition coil to the crankcase housing
and remove the coil.
IO069A
8. Remove the cylinder head cover; then remove the air
shroud.
IO070A
9. Remove the air breather body from the cylinder head
cover. Account for a gasket.

11
IO071
10. Remove the lock nuts and rocker arm pivots securing
the rocker arms to the cylinder head.
11. Remove the push rods; then remove the push rod
guide plate.
IO072A
12. Remove the cap screws securing the head to the cyl-
inder; then remove the head and account for a gasket
and the location of the two dowel pins.
IO073
13. Remove the nut securing the flywheel to the crank-
shaft and starter pulley.
IO069B
14. Using a flywheel puller, remove the flywheel.
IO074
15. Remove the cap screws securing the stator to the
crankcase; then route the stator harness out through
the slot in the crankcase and remove the stator.
IO075A
16. Remove the cap screws securing the crankcase side
cover to the crankcase. Account for dowel pins, gas-
ket, and a crankshaft shim.

12
IO094B
IO077
17. With the piston at TDC, scribe an alignment mark on
the gear of the camshaft directly in-line with the
alignment dot on the crankshaft gear.
IO078A
18.Remove the camshaft; then remove the tappets. Iden-
tify the tappets for proper installation.
IO079A
19. Rotate the crankshaft until the connecting rod cap
screws are accessible.
IO080A
20. Note the relation of the connecting rod journal to the
crankshaft and mark the connecting rod and end cap
for reference during installation; then remove the cap
screws and connecting rod end cap.
IO081A
21. Carefully work the connecting rod/piston up and out
of the cylinder; then remove the crankshaft.
NOTE: For assembling purposes, note the arrow
mark on the dome of the piston is directed to the push
rod opening of the cylinder.
22. Remove the hairpin clip from the governor control
shaft; then remove the shaft and account for the
washer.
IO082A
23. Inspect the crankshaft and governor control shaft oil
seals for cracks or deterioration; then inspect the
crankshaft bearings for roughness or discoloration
and replace if necessary.

13
NOTE: If the seals or bearings of the crankshaft
need to be replaced, see Crankshaft Bearings in Ser-
vicing Components.
Servicing Components
Thoroughly clean all non-electrical components in parts-
cleaning solvent; then remove any carbon buildup from
the cylinder head, piston dome, valves, and valve seats.
Visually inspect all engine components for wear or dam-
age.
CYLINDER HEAD/VALVE ASSEMBLY
NOTE: Remove the valves by pressing down on the
spring retainer and removing the valve keeper.
Account for valve springs, spring retainers, and valve
keepers. Keep all valves and related components as a
set.
When servicing valves and cylinder head assembly,
inspect valve seats, head warpage, valve stems, valve
faces, and valve stem ends for pits, burn marks, or other
signs of abnormal wear. Never reuse the intake valve
seal. Always replace the seal.
NOTE: Discard any valve that fails the listed inspec-
tions. Do not grind the valves. If a valve or cylinder
head is damaged, it must be replaced.
Measuring Cylinder Head Distortion
1. Using a non-metallic carbon removal tool, remove
any carbon buildup from the combustion chamber
being careful not to nick, scrape, or damage the com-
bustion chamber or the sealing surfaces.
2. Inspect the spark-plug hole for any damaged threads.
Repair damaged threads using a heli-coil insert.
3. Inspect the cylinder head for flatness using a
straightedge and a feeler gauge. Acceptable distor-
tion must not exceed 0.004".
IO087
Measuring Valve Stem Runout
1. Support each valve stem end with V Blocks; then
check the valve stem runout using a dial indicator.
ATV-1082
2. Maximum runout must not exceed 0.0004" for both
valves.
Measuring Valve Face Width
1. Using a micrometer, measure the width of the valve
face.
ATV-1004
2. Acceptable valve face width must be at least 0.030".
Measuring Valve Face Runout
1. Mount a dial indicator on a surface plate; then place
the valve stem on a set of V blocks.
2. Position the dial indicator contact point on the out-
side edge of the valve face; then zero the indicator.
ATV1082A
3. Rotate the valve in the V blocks.
4. Maximum runout must not exceed 0.0012".

14
Measuring Valve Guide/Valve Stem
Clearance
1. Using a micrometer and small bore gauge, take
diameter readings on the valve stems and inside the
guides.
2. The stem clearance inside the guide must be within
0.0016-0.0020" for the intake and 0.0020-0.0030"
for the exhaust.
NOTE: Be sure to take readings at more than one
place along the length of each stem and guide.
Lapping Valves
NOTE: Ensure that all carbon has been removed
from the valves.
1. Using a valve lapper, produce a contact pattern on
each valve face by applying a uniform coat of valve
lapping compound to the valve seat and by rotating
and tapping the valve head.
2. Acceptable width of valve seat contact width (mea-
surement A) must be at least 0.03".
GEN-0023
GEN-0024
NOTE: Do not grind the valves. If a valve is dam-
aged, it must be replaced.
3. Lubricate each valve stem with lightweight oil; then
apply a small amount of valve lapping compound to
the entire seating face of each valve.
4. Attach the suction cup of a valve lapping tool to the
head of the valve.
5. Rotate the valve until the valve and seat are evenly
polished.
6. Clean all compound residue from the valve and seat.
Valve Springs
1. When the valve springs are weak, the valve and
valve seat fail to form a good seal, thus allowing gas
to leak past the valve seat causing a loss of power.
Whether or not a valve spring is weak can be deter-
mined by its free length.
GM128D
2. Minimum valve spring free length must not exceed
1.04".
NOTE: With the crankshaft at top dead center on
the compression stroke, install the valve springs and
spring retainers; then compress the valve springs and
install the valve keepers.
CAM LOBE WEAR
Worn cam lobes result in reduced power output. The limit
of cam lobe wear is specified for both intake and exhaust
lobes in terms of cam height to be measured with a
micrometer. Replace the camshaft if not within 1.048-
1.052".
GEN0028B
IO088

15
Measuring Camshaft End Running
Surfaces
1. Using an outside micrometer, measure the running
surfaces of each end of the camshaft. The measure-
ment should be at least 0.592".
IO089
2. Inspect the camshaft bosses of the crankcase and
crankcase cover for cracks, discoloration, and wear.
PISTON ASSEMBLY
NOTE: Oversized pistons are available allowing the
cylinder to be bored oversized.
NOTE: Whenever a piston, rings, or pins are out of
tolerance, they must be replaced.
Cleaning/Inspecting Piston
1. Using a non-metallic carbon removal tool, remove
any carbon buildup from the dome of the piston.
2. Inspect the piston for cracks in the piston pin, dome,
and skirt areas.
3. Inspect the piston for seizure marks or scuffing.
NOTE: If seizure marks or scuffing is detected, the
piston must be replaced.
4. Inspect the perimeter of each piston for signs of
excessive “blowby.” Excessive “blowby” indicates
worn piston rings or an out-of-round cylinder.
Removing Piston Rings
1. Starting with the top ring, slide one end of the ring
out of the ring-groove.
2. Remove each ring by working it toward the dome of
the piston while rotating it out of the groove.
NOTE: Note the location of each ring for proper
installation. When installing new rings, install as a
complete set only.
Cleaning/Inspecting Piston Rings
NOTE: Make a ring-groove cleaning tool by taking
an old piston ring and snapping it into two pieces;
then grind the end of the old ring to a 45° angle and to
a sharp edge.
Using a ring-groove cleaning tool, clean carbon from the
ring-grooves. Be sure to position the ring with its tapered
side up.
Measuring Piston-Ring End Gap
(Installed)
1. Place each piston ring in the wear portion of the cyl-
inder. Use the piston to position each ring squarely in
the cylinder.
NOTE: When measuring a piston ring, it should be
placed into the area of the cylinder where wear is least
(the area is about 0.12" from the upper or lower edge
of the cylinder).
2. Using a feeler gauge, measure each piston-ring end
gap. Acceptable ring end gap must be within 0.008-
0.016" (1st and 2nd rings) or within 0.0079-0.0157"
(oil ring).
IO083
IO090
Piston Ring/Groove Clearance
1. Using a thickness gauge, measure the side clearances
of the 1st and 2nd rings.
2. If the measurements are not within 0.0016- 0.0030"
(1st ring) or 0.0008-0.0024" (2nd ring), replace both
piston and piston rings.
CAUTION
Improper cleaning of the ring-grooves by the use of the
wrong type of ring-groove cleaner will result in severe
damage to the piston.

16
Measuring Piston Skirt/Cylinder
Clearance
1. Measure the cylinder front to back in six places using
a cylinder bore gauge. The amount of wear is the dif-
ference between the largest and smallest readings. If
the determined wear exceeds the limit indicated, bore
to the next oversize by using a boring machine or
replace the cylinder.
GEN-0032
2. Measure the corresponding piston diameter at a point
10 mm above the piston skirt at a right angle to the
piston-pin bore. Piston diameter must be at least
2.205".
IO085
3. Piston skirt to cylinder clearance must be within
0.0006-0.0016".
4. If the piston/cylinder clearance exceeds the limit,
bore the cylinder and use an oversized piston or
replace both cylinder and piston.
Installing Piston Rings
1. Place the oil ring expander into the bottom groove of
the piston allowing the ends to contact each other.
2. Place one end of the thin oil ring between the top of
the oil ring expander and the ring groove; then wind
the ring around the piston until the ring is properly
seated into the ringland of the piston. Repeat this
procedure for the lower thin oil ring.
3. Position the thin oil ring gaps 90° from the gap of the
oil ring expander and 180° from each other.
4. Install the middle and top compression ring with the
I.D. mark directed toward the dome of the piston.
NOTE: The top compression ring can be identified
by the chrome (silver) face of the ring.
Measuring Piston Pin Diameter
1. Measure the piston pin diameter at each end and in
the center. If measurement is less than minimum
specifications, the piston pin must be replaced.
2. Piston pin diameter must be within 0.6297-0.6299".
IO086
Measuring Piston Pin Bore Diameter
1. Insert an inside dial indicator into the piston-pin
bore. Take two measurements to ensure accuracy.
2. Piston pin bore must not exceed 0.433".
ATV-1069
CYLINDER/CYLINDER HEAD
NOTE: If the cylinder/cylinder head assembly can-
not be trued, they must be replaced.
Cleaning/Inspecting Cylinder Head
1. Using a non-metallic carbon removal tool, remove
any carbon buildup from the combustion chamber
being careful not to nick, scrape, or damage the com-
bustion chamber or the sealing surface.
CAUTION
Never allow the ends of the oil ring expanders to over-
lap. This allows a loss of oil control and incorrect ten-
sion of the ring.
CAUTION
Incorrect installation of the piston rings will result in
engine damage.

17
2. Inspect the spark plug hole for any damaged threads.
Repair damaged threads using a “heli-coil” insert.
3. Place the cylinder head on the Surface Plate covered
with #400 grit wet-or-dry sandpaper. Using light
pressure, move the cylinder head in a figure-eight
motion. Inspect the sealing surface for any indication
of high spots. A high spot can be noted by a bright
metallic finish. Correct any high spots before assem-
bly by continuing to move the cylinder head in a fig-
ure-eight motion until a uniform bright metallic
finish is attained.
Cleaning/Inspecting/Measuring
Cylinder Distortion
1. Wash the cylinder in parts-cleaning solvent.
2. Check the gasket surface of the cylinder for distor-
tion with a straightedge and thickness gauge taking a
clearance reading at several places. If the largest
reading at any position of the straightedge exceeds
the limit, replace the cylinder.
3. Maximum cylinder distortion must not exceed
0.004".
IO087
4. Inspect the cylinder for pitting, scoring, scuffing,
warpage, and corrosion. If marks are found, repair
the surface using the Ball Hone (see Honing Cylin-
der sub-section).
5. Place the cylinder on the surface plate covered with
#400 grit wet-or-dry sandpaper. Using light pressure,
move the cylinder in a figure-eight motion. Inspect
the sealing surface for any indication of high spots.
A high spot can be noted by a bright metallic finish.
Correct any high spots before assembly by continu-
ing to move the cylinder in a figure-eight motion
until a uniform bright metallic finish is attained.
Honing Cylinder
1. Wash the cylinder in parts-cleaning solvent.
2. Inspect the cylinder for pitting, scoring, scuffing, and
corrosion. If marks are found, repair the surface
using the Ball Hone.
NOTE: To produce the proper 45° crosshatch pat-
tern, maintain a low drill RPM. If honing oil is not
available, use a lightweight, petroleum-based oil.
Thoroughly clean the cylinder after honing using
detergent soap and hot water and dry with com-
pressed air; then immediately apply oil to the cylinder
bore. If the bore is severely damaged or gouged, the
cylinder must be replaced.
3. If the cylinder bore measurement exceeds the limit,
hone the cylinder and install an oversized piston or
replace the cylinder.
MEASURING CONNECTING ROD
SMALL END BORE INSIDE DIAMETER
1. Using a small bore gauge, measure the connecting
rod small end bore inside diameter.
2. Measurement must be within 0.6301-0.6307".
GEN-0034
3. If the difference between the connecting rod small
end bore inside diameter and the piston pin outside
diameter exceeds the limit, replace both connecting
rod and piston pin. The measurements must be
within 0.0001-0.0002" of each other.
GEN-0035
CRANKSHAFT RUNOUT
1. Support the crankshaft using a set of V blocks; use a
dial indicator to read crankshaft runout.
NOTE: The contact point of the dial indicator
should be on the seal area of the crankshaft.
2. Total indicator reading must not exceed 0.0008".
CAUTION
Water or parts-cleaning solvent must be used in con-
junction with the wet-or-dry sandpaper or damage to
the sealing surface may result.
CAUTION
Water or parts-cleaning solvent must be used in con-
junction with the wet-or-dry sandpaper or damage to
the sealing surface may result.

18
GEN-0031
3. If not within specification, either straighten the
crankshaft or replace it.
MEASURING CONNECTING ROD BIG
END SIDE CLEARANCE
1. Check the connecting rod side clearance by using a
thickness gauge. If the clearance exceeds the limit,
replace the connecting rod or crankshaft.
2. Clearance measurement must be within 0.008-
0.024".
GEN-0036
MEASURING CRANK PIN/
CONNECTING ROD CLEARANCE
1. Measure the crank pin diameter. Measurement must
be at least 1.102".
GEN-0037
2. Measure the connecting rod big end bore inside
diameter. Measurement must be within 1.1023-
1.1029".
GEN-0038
3. Measure the crank pin/connecting rod clearance.
Measurement must be within 0.0002-0.0008".
GEN-0039
CRANKSHAFT BEARINGS
0744-992
Removing
1. Using a flat-blade screwdriver, carefully work the oil
seal from side-to-side out of the crankcase and cover.
2. Using a suitable press and with the crankcase or
crankcase cover secured into position, carefully heat
the case; then press the bearings out of the case.
NOTE: Thoroughly clean the bearing areas of the
crankcase and crankcase cover and inspect for any
nicks or imperfections of the bearing bosses of the
case.
CAUTION
Never reuse the crankshaft bearings. If the bearings
have been pressed out of the crankcase or crankcase
cover, they must be discarded.

19
Installing
1. Secure the crankcase and press the new bearing into
the boss of the crankcase and crankcase cover.
2. With the bearings installed and using a suitable seal
driver, install the oil seals with the spring side of the
seal facing the bearing; then coat the wear surfaces
of the seals with a film of grease.
CARBURETOR INSULATOR PLATE
1. Inspect for cracks, scoring, pitting, imperfections, or
warping.
2. Inspect the sealing surfaces for trueness by placing
each on the surface plate covered with #400 grit wet-
or-dry sandpaper. Using light pressure, move both
sides in a figure-eight motion. Inspect the sealing
surfaces for any indication of high spots or warping.
Correct highs spots by continuing to move each side
in a figure-eight motion. Warped components must
be replaced.
A932
Assembling
NOTE: The use of new gaskets and seals is recom-
mended when assembling the engine.
NOTE: Prior to assembling the engine, use parts
cleaning solvent and compressed air and thoroughly
clean the threaded holes of the crankcase and cylinder
and head to properly tighten.
NOTE: When the use of a lubrication is indicated,
use clean engine oil.
1. Lubricate the piston pin, connecting rod, and piston
pin bore with engine oil; then install the piston to the
connecting rod and secure the piston pin with the cir-
clips directed either up or down.
IO091A
NOTE: Coat the cylinder wall, connecting rod bear-
ing surface, and the crankshaft with engine oil.
2. Install the crankshaft into the crankcase; then with
the piston rings properly oriented (end gap 120°
apart), compress the piston rings and install the pis-
ton and connecting rod assembly taking care not to
damage the crankshaft and connecting rod.
0745-001
3. Note the marks on the connecting rod and end cap
made during disassembly.
IO081A
CAUTION
When installing the new bearings, always press against
the outside race of the bearing.
CAUTION
Water or parts-cleaning solvent must be used in con-
junction with the wet-or-dry sandpaper or damage to
the sealing surfaces may result.
! WARNING
Always wear safety glasses when drying components
with compressed air.
CAUTION
The arrow of the piston must be directed toward the
push rod opening of the cylinder.