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Harley Davidson 1986-2003 XL/XLH Sportster. Service Manual - page 34

346

CHAPTER TEN

Strainer

Fuel tank

Nut

OFF

RES

Clamp

Hose

2. Coat the fuel valve threads with pipe sealant.

3. Insert the fuel valve into the tank and tighten the nut se-
curely.

4. Install the fuel tank as described in this chapter.

EXHAUST SYSTEM

Removal/Installation

1. Place the motorcycle on the sidestand.

2. Loosen the muffler clamps and brackets (Figure 52).

3. Remove the muffler mount bolts (Figure 53).

4. Slide the mufflers (Figure 54) off the exhaust pipes.

5. Loosen and remove the exhaust pipe nuts from the cyl-
inder head studs (Figure 55).

6. Remove the exhaust pipe assembly (Figure 56).

7. Install by reversing the preceding removal steps while
noting the following:

a. Replace the exhaust port gaskets (Figure 57) if worn

or damaged. During installation, make sure the gas-
kets are installed in the cylinder heads correctly.

b. Install all parts and finger tighten fasteners only.

Then tighten the exhaust nuts at the cylinder head and
work back to the mufflers. This will minimize ex-
haust leaks at the cylinder heads. Make sure all fas-
teners are tightened securely.

Inspection

1. Inspect all pipes for rust or corrosion.
2. Remove all rust from exhaust pipes and muffler mating
surfaces.
3. Replace rusted or damaged exhaust system components.
4. Replace damaged exhaust pipe snap rings.
5. Replace damaged heat shields.

EVAPORATIVE EMISSION CONTROL SYSTEM

(CALIFORNIA MODELS)

The evaporative emission control system prevents gasoline

vapor from escaping into the atmosphere. When the engine is
not running, the system directs the fuel vapor from the fuel
tank through the vapor valve and into the carbon canister.

When the engine is running, these vapors are drawn

through a purge hose and into the carburetor where they
burn in the combustion chambers. The vapor valve also
prevents gasoline vapor from escaping from the carbon
canister if the motorcycle falls onto its side.

Carbon Canister Inspection

Refer to Figure 58 and Figure 59 for component place-

ment and hose routing. Before removing the hoses from any
of the parts, mark the hose and fitting.

FUEL, EMISSION CONTROL AND EXHAUST SYSTEMS (1986-1987 MODELS)

347

EVAPORATIVE EMISSION CONTROL SYSTEM

(CALIFORNIA)

This end toward
fuel tank

1. Frame tubes
2. Ignition coil bracket
3. Cable wrap
4. Hose
5. Air filter assembly
6. Canister
7. Vapor valve
8. Hose
9. Hose

10. Fuel tank
11. Hose clip
12. Gas tank vent tube
13. Carburetor
14. Frame

WARNING

Make sure the fuel tank vapor hoses are
routed so they cannot contact hot engine or
exhaust components.

1. Check all emission control lines and hoses to make sure
they are correctly routed and connected.
2. Make sure there are no kinks in the lines or hoses. Also
inspect the hoses and lines routed near engine hot spots for
excessive wear or burning.
3. Check the physical condition of all lines and hoses in the
system. Check for cuts, tears or loose connections. These
lines and hoses are subjected to various temperatures and
operating conditions, and eventually become brittle and
crack. Replace damaged lines and hoses.
4. Check all components in the emission control system for
damage, such as broken fittings.
5. If canister replacement is required, mark the hoses and
prior to disconnecting the hoses from the canister.

Vapor Valve Replacement

The vapor valve (7, Figure 58) is part of the fuel pressure

relief system. The fuel tank vapor expands as the fuel tank
temperature rises. The vapor valve relieves excess pressure
within the tank.

The lower hose is connected to the carbon canister.

1. Label the upper hose and lower hose where they are con-
nected to the vapor valve fittings.

2. Disconnect the hoses from the vapor valve and remove
the vapor valve.

WARNING

The vapor valve must be mounted in a vertical
position in order to operate correctly.

3. Position the vapor valve with the long neck fitting at the
top and attach the upper and lower hoses to the vapor valve.

348

CHAPTER TEN

CARBON CANISTER ASSEMBLY

1 1/2 in.

1. Clamp
2. Bracket
3. Rubber mount
4. Nut
5. Washer
6. Carbon canister

Table 1 CARBURETOR SPECIFICATIONS

883 models

1100 models

Carburetor jet sizes

1986 models

Main jet

155

Pilot jet

1987 models

Main jet

155

150

Pilot jet

Float height

0.63-0.67 in.

(16.0-17.0 mm)

Table 2 FUEL, EMISSION CONTROL AND EXHAUST SYSTEM TORQUE SPECIFICATIONS

ft.-lb.

in.-lb.

N•m

Backplate-to-carburetor screws

–

36-60

4-7

Backplate-to-cylinder head bolts

–

120-144

14-16

Fuel tank mounting bolts

–

Intake manifold mounting

bolts and nuts

–

72-120

8-14

Intake manifold-to-carburetor nuts

–

180-204

20-23

FUEL, EMISSION CONTROL AND EXHAUST SYSTEMS (1986-1987 MODELS)

349

CHAPTER ELEVEN

FUEL, EMISSION CONTROL AND EXHAUST

SYSTEMS (1988-2003 MODELS)

This chapter covers fuel, emissions control and exhaust

systems. Air filter service is covered in Chapter Three. Ta-
bles 1 and Table 2 are at the end of the chapter.

Refer to

Safety

in Chapter One prior to working on the

fuel system.

AIR FILTER BACKPLATE

Removal/Installation

NOTE

Early models are equipped with a foam-type
filter. Later models are equipped with a pa-
per-mesh filter as shown in

Figure 1

1. Remove the air filter element (Chapter Three).

2. Remove the backplate bolts (A, Figure 2).

CAUTION

Do not remove the screws from the backplate
unless the backplate requires replacement.
Completely removing the screw damages the
backplate insert sleeve threads.

3. Loosen the screws (B, Figure 2) 1 or 2 turns at a time in
a crisscross pattern until they disengage from the carburetor
holes. Remove the backplate and screws.

4. On California models, label and then disconnect the
hoses from the backplate (Figure 1). Disconnect the butter-
fly valve solenoid wiring 4-pin connector.
5. If necessary, replace the carburetor gasket.
6. Install by reversing the preceding steps while noting the
following:

a. Install the backplate-to-carburetor screws first to

align the backplate, but do not tighten the screws. On
HDI models, use the air filter retaining screws, which
also serve to secure the backplate to the carburetor.

b. After aligning the backplate to the carburetor, loosely

install the backplate-to-cylinder head bolts.

c. Tighten the backplate-to-carburetor screws to 36-60

in.-lb. (4-7 N•m). On HDI models, tighten the air fil-
ter retaining screws to 20 in.-lb. (2 N•m).

d. Tighten the backplate-to-cylinder head bolts to

120-144 in.-lb. (14-16 N•m).

CARBURETOR

Operation

The carburetor atomizes fuel in correct proportions with

the air drawn in through the air intake. At the primary throt-
tle opening (idle), a small amount of fuel is siphoned
through the pilot jet by the incoming air. As the throttle is
opened further, the air stream begins to siphon fuel through

the main jet and needle jet. The tapered needle increases the
effective flow capacity of the needle jet as it is lifted, and
occupies progressively less of the area of the jet. At full
throttle, the carburetor venturi is fully open and the needle
is lifted far enough to permit the main jet to flow at full ca-
pacity.

The choke circuit is a starting enrichment valve system.

The choke knob under the fuel tank on the left side of the
engine opens an enrichment valve. In the open position, the
slow jet discharges a stream of fuel into the carburetor
venturi enriching the mixture when the engine is cold.

The accelerator pump circuit reduces engine hesitation

by injecting a fine spray of fuel into the carburetor intake
passage during sudden acceleration.

Removal/Installation

1. Remove the air filter (Chapter Three).
2. Remove the air filter backplate as described in this
chapter.
3. Turn the fuel valve off.

NOTE

It is easier to remove the enrichener cable
while it is attached to the carburetor.

4. Remove the enrichener bracket mounting screw (Figure
3) and allow the bracket to rest on top of the intake manifold.

FUEL, EMISSION CONTROL AND EXHAUST SYSTEMS (1988-2003 MODELS)

351

AIR FILTER ASSEMBLY (1990-2003 MODELS)

1. Gasket
2. Canister-to-air-filter

hose (California models)

3. Carburetor overflow vent

hose (California models)

4. Backplate
5. Butterfly valve solenoid

wiring harness (California models)

6. Allen bolt
7. Screw
8. Air filter
9. Cover

10. Screw

5. Push the rubber boots (Figure 4) off the throttle cable
adjusters.
6. Loosen the throttle friction screw .
7. Loosen both throttle cable adjuster jam nuts (A, Figure
5), then turn the cable adjusters (B).

NOTE

Refer to

Fuel Hose And Clamps

in this chap-

ter when disconnecting the fuel hose.

8. Label and then disconnect the fuel supply hose from the
carburetor fitting.
9A. On 1988-1990 models, loosen the hose clamp, then
pull the carburetor out of the manifold.
9B. On 1991-2003 models, twist and pull the carburetor off
the seal ring and intake manifold.
10. Identify and label all carburetor hoses for correct rein-
stallation. Then disconnect the hoses from the carburetor.
11. There are two different throttle cables. Label the two
cables at the carburetor before disconnecting them. One is
the throttle control cable (A, Figure 6) and the other is the
idle control cable (B). Disconnect the throttle control cable
and the idle control cable from the carburetor cable guide
and the throttle pulley.
12. Drain the gasoline from the carburetor.
13. If necessary, service the intake manifold as described
in this chapter.
14. Inspect the manifold seal ring (Figure 7) for wear,
hardness, cracks or other damage. Replace if necessary.
15. Cover the intake manifold opening.

Installation

1. If removed, seat the manifold seal ring (Figure 7) onto
the intake manifold. Make sure it is correctly seated to
avoid a vacuum leak.
2. Route the starting enrichment valve cable between the
cylinders and towards the mounting bracket on the left side.
3. Connect the idle cable to the carburetor as follows:

a. The idle cable has the small spring (C, Figure 6) on

the end of the cable.

b. Insert the idle cable sheath into the rear cable bracket

guide on the carburetor.

c. Attach the end of the idle cable (B, Figure 6) to the

throttle pulley.

4. Connect the throttle cable to the carburetor as follows:

a. Insert the throttle cable sheath into the front cable

bracket guide on the carburetor.

b. Attach the end of the throttle cable (A, Figure 6) to

the throttle pulley.

5. Operate the throttle a few times. Make sure the throttle
pulley operates smoothly with no binding. Also make sure
both cable ends are seated squarely in the cable bracket
guides and in the throttle pulley.
6. Connect any disconnected hoses to the carburetor.

CAUTION

The carburetor must fit squarely onto the in-
take manifold. If it is misaligned, it may dam-
age the manifold seal ring, resulting in a
vacuum leak.

NOTE

To ease installation of the carburetor, apply a
light coat of liquid dish soap to the carburetor
spigot before insertion into the manifold seal
ring .

7A. On 1988-1990 models, insert the enrichener cable
(Figure 3) between the cylinders and above the intake man-

352

CHAPTER ELEVEN

ifold. Install the hose clamp around the carburetor spigot,
then install the carburetor into the intake manifold until it
bottoms (Figure 8). Position the carburetor so it sits square
and vertical with the manifold. Tighten the hose clamp.
7B. On 1991-2003 models, insert the enrichener cable (Fig-
ure 3) between the cylinders and above the intake mani-
fold. Align the carburetor with the intake manifold and
push the carburetor into the manifold seal ring until it bot-
toms (Figure 8). Position the carburetor so it sits square and
vertical with the manifold.
8. Secure the enrichener bracket to the cylinder head
bracket with its mounting screw (Figure 3).
9. Install the air filter backplate as described in this chapter.

WARNING

Make sure that all evaporative emission con-
trol hoses are routed so they cannot contact
any hot engine or exhaust component. These
hoses contain flammable vapors. If a hose
melts from contacting a hot part, leaking va-
pors may ignite, causing severe motorcycle
damage and rider injury.

CAUTION

Interchanging the vacuum hose connections
will reduce engine performance

10. On California models, reconnect all evaporative emis-
sions control system hoses following notes made prior to

disassembly. Refer to the

Evaporative Emissions Control

System

in this chapter to confirm the correct connection of

each hose.
11. Adjust the throttle and enrichener cables (Chapter Three).

Disassembly

Refer to Figure 9.

1. Unscrew and remove the enrichener cable (Figure 10).
2. If not previously removed, remove the throttle cable
bracket screw and lockwasher and remove the bracket (Fig-
ure 11).
3A. On 1988 models, remove the float bowl from the carbu-
retor. Account for the float bowl O-ring.

NOTE

An accelerator pump is installed on 1989-
2003 models. Note the position of the throttle
and pump rods when removing the float bowl.

3B. On 1989-2003 models, remove the float bowl as fol-
lows:

a. Remove the screws and washers securing the float

bowl (Figure 12) to the carburetor. Remove the float
bowl from the carburetor while allowing the pump rod
(Figure 13) to withdraw from the boot on the bowl.

b. Disconnect the pump rod from the lever assembly on

the carburetor (Figure 14).

c. Pull the boot (Figure 15) off the float bowl.

4A. On 1988-1991 models, remove the float pin (Figure 16)
and lift off the float and needle valve assembly (Figure 17).
4B. On 1992-2003 models, remove the float pin (Figure 18)
and lift off the float and needle valve assembly (Figure 19).
5. The main jet is screwed into the top of the needle jet
holder. Either remove the main jet (Figure 20) and then the
needle jet holder (Figure 21) or remove the needle jet
holder with the main jet attached.
6. Remove the needle jet from the needle jet bore (Figure
22) in the carburetor.

CAUTION

If the screwdriver used to remove the pilot jet
is too small it may damage the top of the jet. If
necessary, grind a screwdriver tip to fit.

7. Remove the pilot jet (Figure 23).
8. Remove the remaining cover screws and washers and
remove the cover (Figure 24) and spring (Figure 25).
9. Remove the vacuum piston (Figure 26) from the carbu-
retor housing. Do not damage the jet needle sticking out of
the bottom of the vacuum piston.
10. Remove the spring seat (A, Figure 27) and jet needle
(B) from the vacuum piston.
11. On 1989-2003 models, remove the accelerator pump
diaphragm using the following procedure:

a. Remove the screws and lockwashers holding the

pump cover (Figure 28) to the float bowl and remove
the cover.

FUEL, EMISSION CONTROL AND EXHAUST SYSTEMS (1988-2003 MODELS)

353

354

CHAPTER ELEVEN

1989-2003 models

FUEL, EMISSION CONTROL AND EXHAUST SYSTEMS (1988-2003 MODELS)

355

CARBURETOR

1. Screw
2. Lockwasher
3. Flat washer
4. Cover
5. Spring
6. Spring seat
7. Jet needle
8. Vacuum piston
9. Cable guide

10. Spring
11. Enrichener valve
12. Body
13. Vacuum fitting
14. Idle adjustment

screw

15. Washers
16. Spring
17. Screw
18. Throttle cable

bracket

19. Lockwasher
20. Screw
21. Needle jet
22. Needle jet holder
23. Main jet
24. Fuel valve and clip
25. Float
26. Pin
27. Pilot jet
28. Overflow pipe
29. O-ring
30. Lockwasher

31. Screw
32. Float bowl

(1988 models)

33. Hose (1988 models)
34. Clamp (1988 models)
35. Fuel overflow

fitting (1988 models)

36. Cotter pin
37. Washer
38. Roller
39. Pump lever assembly
40. Lockwasher
41. Screw
42. E-clip
43. Throttle rod
44. Pump rod
45. Washers
46. Spring
47. Boot
48. Drain screw
49. O-ring
50. Diaphragm
51. Spring
52. O-ring
53. Cover
54. Lockwasher
55. Screw
56. O-ring
57. Accelerator pump

nozzle

58. Float bowl

356

CHAPTER ELEVEN

b. Remove the pump cover O-ring (Figure 29).
c. Remove the spring (A, Figure 30) and diaphragm (B).

NOTE

Replacement parts are not available for the
throttle plate (

Figure 31

) assembly. Do not

loosen the screws or remove the throttle plate.

Inspection

CAUTION

Do not clean rubber, plastic or other non-
metal parts in carburetor cleaner. The chemi-
cal will destroy these parts.

FUEL, EMISSION CONTROL AND EXHAUST SYSTEMS (1988-2003 MODELS)

357

1. Clean all metal parts in carburetor cleaner. Follow the
manufacturer’s instructions.

2. Remove all parts from the cleaner and blow dry with
compressed air. Blow out the jets (Figure 32) with com-
pressed air. Do not use a piece of wire or small drill bit to
clean them, as minor gouges in a jet can alter the flow rate
and upset the air/fuel mixture.

3. Make sure the needle jet holder (Figure 32) bleed tube
orifices are clear.

4. Make sure all fuel and air openings are clear. Blow them
out with compressed air if necessary.

5. Check the float assembly for leaks; see A, Figure 33
(1988-1991 models) or Figure 34 (1992-2003 models).
Place the float in a container full of water and push it down.
It should float and there should be no bubbles. Replace the
float assembly if it leaks.

6. Check the float needle (B, Figure 33) and seat (Figure
35) contact areas closely. Both contact surfaces should be
smooth with no gouging or other damage. Replace the nee-
dle if damaged. The seat is a permanent part of the carbure-
tor housing; if damaged, replace the housing.

7. A damaged accelerator pump diaphragm (Figure 36)
will cause poor acceleration. Hold the diaphragm up to a
strong light and check the diaphragm for pin holes, cracks
or other damage. Replace if necessary.

358

CHAPTER ELEVEN

8. Remove the accelerator pump nozzle (A, Figure 37) and
O-ring (B) from the float bowl. Clean the nozzle with com-
pressed air.

9. Replace the pump rod if bent or worn.

10. Inspect all O-rings and replace if necessary. When re-
placing an O-ring, make sure the new O-ring fits in its
groove properly. See Figure 38, typical.

11. Inspect the pilot jet (Figure 32) for wear or damage.
Check the slot in the top of the jet for cracks or breaks. Re-
place if damaged.

12. Inspect the vacuum piston (Figure 39) as follows:

a. Check the spring (Figure 25) for fatigue, stretching,

distortion or other damage.

b. Check the vacuum passage through the bottom of the

piston for contamination. Clean passage if blocked.

c. The sides of the piston ride in grooves machined in

the carburetor bore. Check these sides for roughness,
nicks, cracks or distortion. If the piston sides are
damaged, check the mating grooves in the carburetor
for damage. Minor roughness can be removed with
emery cloth or by buffing. If the sides are severely
damaged, replace the vacuum piston.

d. Hold the vacuum piston up to a light and check the di-

aphragm (Figure 40) for holes, tearing, cracks, age
deterioration or other damage. Check the diaphragm
where it is mounted against the piston. If the dia-
phragm is damaged, replace the vacuum piston.

FUEL, EMISSION CONTROL AND EXHAUST SYSTEMS (1988-2003 MODELS)

359

e. Check the jet needle (B, Figure 27) for bending or

damage.

13. Inspect the enricher system as follows:

a. Check for a rough or damaged enrichener valve.

Check the needle (Figure 41) on the end of the
enrichener valve for bending or contamination.

b. Check the enrichener valve spring for fatigue,

stretching or distortion.

c. The enrichener valve chamber (A, Figure 42) in the

carburetor must be clean. Clean the chamber, making
sure the enrichener valve air inlet and the air/fuel pas-
sages are clear.

d. Check the enrichener valve cable (Figure 43) for

kinks or other damage.

14. Check the throttle rod (Figure 44) and all external car-
buretor components for missing or damaged parts.

15. Check that the throttle valve shaft E-clip (B, Figure
42) is properly secured in the groove on the end of the
shaft.

Assembly

Refer to Figure 9.

1. Prior to assembly, refer to

Inspection

in this section.

Clean all parts before assembly.

360

CHAPTER ELEVEN

NOTE

Before installing new jets, check the jet size
and compare it to the old jet. Refer to

Table 1

for original equipment jet sizes.

2. Place the pilot jet (Figure 45) into the passage and
tighten it with the same screwdriver used during removal.
3. The needle jet has two different sides and can be in-
stalled incorrectly. Install the needle jet into its passage
(Figure 46) so that the end with the larger opening faces up
toward the vacuum piston chamber.
4. Install the needle jet holder (Figure 47) into the main jet
passage and tighten it securely.
5. Install the main jet (Figure 48) onto the end of the nee-
dle jet holder and tighten securely.
6A. On 1988-1991 models, install the float as follows:

a. Install the fuel valve onto the float (Figure 49) and

position the float onto the carburetor so the valve
drops into its seat.

b. Align the float pivot arm with the two carburetor

mounting posts and slip the pin through the float
pivot arm and mounting posts (Figure 50).

6B. On 1992-2003 models, install the float as follows:

a. Install the fuel valve onto the float (Figure 51) and

position the float onto the carburetor so that the valve
drops into its seat.

b. Align the float pivot arm with the two carburetor

mounting posts and slip the pin through the float
pivot arm and mounting posts (Figure 52).

FUEL, EMISSION CONTROL AND EXHAUST SYSTEMS (1988-2003 MODELS)

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