Haynes Yamaha Xv V Twins Manual

							
3B-6 
Chapter 3 Part B Fuel and exhaust systems (XV700-1100 models)

6.3 Squeeze the clip (arrow) and slide it down the fuel line, then

pry the fuel line off the fitting 
6.4 Loosen the air hose clamp screws (A) and the choke cable

retaining screw (B), then disconnect the choke cable (C)

from the carburetor

6 Carburetors and intake joints - removal and

installation

Warning: Gasoline (petrol) is extremely flammable, so take extra

precautions when you work on any part of the fuel system. Dont smoke

or allow open flames or bare light bulbs near the work area, and dont

work in a garage where a natural gas-type appliance (such as a water

heater or clothes dryer) is present. If you spill any fuel on your skin,

rinse it off immediately with soap and water. When you perform any

kind of work on the fuel system, wear safety glasses and have an

extinguisher suitable for class B fires (flammable liquids) on hand.

Removal

Refer to illustrations 6.3, 6.4, 6.5a, 6.5b and 6.7

1 Lift or remove the seat as necessary (see Chapter 7) and remove

the fuel tank (see Section 2). If youre working on a 1984 or later model,

remove the mixture control valve case (see Chapter 7).

2 Disconnect the throttle and choke cables (see Section 9).

3 Disconnect the fuel inlet lines from the carburetor fittings (see

illustration). Label and disconnect all hoses, vacuum lines and wires.

4 Loosen the clamp screws and disconnect the air cleaner hoses

from the carburetors (see illustration). Detach the hoses from the air

cleaner and carburetors and remove them from the motorcycle.

5 Loosen the clamp screws on the carburetor intake joints. Twist

the carburetors clockwise to free them from the joints and lift them out

(see illustrations). 
6 After the carburetors have been removed, stuff clean rags into the

joints or intake ports to prevent the entry of dirt or other objects.

7 Inspect the air cleaner hoses and carburetor intake joints. If

theyre cracked or brittle, replace them (see illustration).

Installation

8 Installation is the reverse of the removal steps, with the following

additions:

a) Lightly lubricate the ends of the throttle cable(s) and the choke

cable with multi-purpose grease and attach them to the throttle

pulley and choke lever. Make sure the accelerator cable (and

decelerator cable if equipped) are in their proper positions.

b) Make sure the carburetor is seated securely in the intake joints

and the air cleaner hoses are fitted securely over the carburetors,

then tighten the clamping band screws.

c) Adjust the throttle grip freeplay (see Chapter 1).

d) Check and, if necessary, adjust the idle speed and carburetor

synchronization (see Chapter 1).

7 Carburetors - disassembly, inspection, cleaning and

reassembly

Warning: Gasoline (petrol) is extremely flammable, so take extra

precautions when you work on any part of the fuel system. Dont smoke

or allow open flames or bare light bulbs near the work area, and dont

6.5a Loosen the intake joint clamp screws

and twist the carburetors clockwise ... 
6.5b ... to free them from

the intake joints 
6.7 Label and disconnect any vacuum

hoses attached to the intake joints 
						

							
Chapter 3 Part B Fuel and exhaust systems (XV700-1100 models)

3B-7

7.1 Carburetors (XV700-1100,1981 through 1987 US and

all UK models) - exploded view

1 Vacuum chamber cover screws

2 Lockwashers

3 Upper bracket

4 Vacuum chamber cover

5 Piston spring

6 Vacuum piston

7 Jet needle

8 Spring

9 Plastic Allen screw

10 Needle jet

11 Choke control plate

12 Cotter pin

13 Washer

14 Screw

15 Lockwasher

16 Pilot adjustment screw

17 Spring

18 Spring

19 Screw

20 Washer

21 Throttle stop screw {rear carburetor)

22 Locknut

23 Main jet

24 Sealing washer

25 Pilot jet

26 Needle valve and seat

27 Sealing washer

28 Floats

29 Float pivot pin

30 Gasket

31 Float chamber

32 Drain screw

33 Float chamber screws

34 Lockwashers

35 Lower bracket

36 Screws

37 Lockwashers

38 Throttle linkage pivot

39 Washers

40 Bushing

41 E-clip

42 Choke control plate

43 Bushing

44 Throttle stop screw

45 Spring

46 Screw

47 Lockwasher

48 Cap

49 Choke plunger retaining plug

50 Choke plunger

51 Spring

52 Washer

53 Choke linkage rod

54 Cotter pin

55 Washer

56 Pilot screw

57 O-ring

58 Spring

work in a garage where a natural gas-type appliance (such as a water

heater or clothes dryer) is present. If you spill any fuel on your skin,

rinse it off immediately with soap and water. When you perform any

kirfd of work on the fuel system, wear safety glasses and have a fire

extinguisher suitable for class B type fires (flammable liquids) on hand. 
1981 through 1987 US and all UK models

Disassembly

Refer to illustrations 7.1, 7.3, 7.4, 7.5a, 7.5b, 7.6, 7.7, 7.8, 7.9, 7.10,

7.11, 7.12a, 7.12b, 7.13, 7.14a, 7.14b and 7.15

1 Remove the carburetors from the machine as described in

Section 6. Set the assembly on a clean working surface. Note: Work

on one carburetor at a time to avoid getting parts mixed up (see

illustration). Most disassembly and cleaning procedures can be

accomplished without separating the carburetors. 
						

							
3B-8 
Chapter 3 Part B Fuel and exhaust systems (XV700-1100 models)

7.3 Remove the cotter pin and washer

and disconnect the choke linkage rod 
7.4 Remove the screws and detach the

bottom bracket 
7.5a Note carefully how the carburetors

fit together...

7.5b ... then pull them apart

7.6 Remove the E-clip and separate the linkage assembly

2 Remove the screws and detach the top bracket from the

carburetor assembly.

3 Remove the cotter pin and washer and disconnect the choke

linkage rod from the left carburetor (see illustration).

4 Remove the screws and detach the bottom bracket (see

illustration). 
5 Carefully note how the carburetors fit together, then pull them

apart (see illustrations).

6 Detach the E-clip from the center pivot of the throttle linkage and

separate the two halves of the linkage assembly (see illustration).

7 Remove the vacuum chamber cover screws. Take off the cover

and gasket and remove the piston spring (see illustration).

7.7 Remove the screws and lift off the vacuum chamber

cover, spring and gasket 
7.8 Slide the vacuum piston out of the carburetor 
						

							
Chapter 3 Part B Fuel and exhaust systems (XV700-1100 models)

3B-9

7.9 Slip the choke control plate fingers

out of the groove in the choke plunger 
7.10 Unscrew the choke plunger cap

and take the plunger out of the

carburetor body 
7.11 Remove the float chamber

cover and gasket

7.12a Push the float pivot pin partway out

with a thin punch, then pull it clear ... 
7.12b ... and lift out the floats together

with the needle valve 
7.13 Unscrew the needle valve seat and

remove it together with its sealing washer

8 Taking care not to tear the diaphragm, lift the piston and jet

needle out of the carburetor (see illustration).

9 Detach the choke control plate and slip it out of its groove in the

choke plunger (see illustration).

10 Unscrew the choke plunger from the carburetor (see illustration).

11 Remove the float chamber cover screws and lift off the cover and

gasket (see illustration).

12 Slide the float off its pivot pin and lift out the float together with

the needle valve (see illustrations): 
13 Unscrew the needle valve seat and remove it, together with the

sealing washer and filter cap (see illustration).

14 Make sure the screwdriver is an exact fit in the slot of the pilot jet,

then unscrew it (see illustration). Unscrew the main jet and remove its

sealing washer (see illustration).

15 Turn the carburetor over and tap it on your hand so the needle jet

slides down out of the carburetor body (see illustration). Remove the

needle jet through the throttle bore.

16 The pilot (idle mixture) screw is located in a passage in the

7.14a Unscrew the pilot jet...

7.14b ... and the main jet and

sealing washer 
7.15 Tap the carburetor in your hand to

shake the needle jet free of its bore 
						

							
3B-10 
Chapter 3 Part B Fuel and exhaust systems (XV700-1100 models)

7.17a Remove the plastic Allen screw, the spring

and jet needle ... 
7.17b ... then separate the components

carburetor body. On US models, this screw is hidden behind a plug

which wili have to be removed if the screw is to be taken out. To do

this, drill a hole in the plug, being careful not to drill into the screw, then

pry the plug out or remove it with a small slide hammer. On all models,

turn the pilot screw in, counting the number of turns until it bottoms

lightly. Record that number for use when installing the screw. Now

remove the pilot screw along with its spring, washer and O-ring (see

illustration 7.1).

Inspection

Refer to illustrations 7.17a, 7.17b, 7.17c, 7.18, 7.23, 7.24, 7.26 and 7.27

17 Remove the plastic Allen screw from inside the piston, then

remove the jet needle and spring (see illustration). Separate the screw

and spring from the jet needle (see illustration). Check the jet needle

for straightness by rolling it on a flat surface (such as a piece of glass).

Replace it if its bent or if the tip is worn. Check the jet needle and the

needle jet (see illustration) for wear where they contact each other

and replace them if theyre worn. Make sure the small holes in the

needle jet are clear.

18 Check the operation of the choke plunger (see illustration). If it

doesnt move smoothly, replace it,along with the return spring. Inspect

the needle on the end of the choke plunger and replace it if its worn.

19 Check the tapered portion of the pilot screw for wear or damage.

Replace the pilot screw if necessary. 
7.17c Check the needle jet for wear and clogged holes

7.18 Check the choke plunger for sticky operation

and a worn needle 
7.23 Check the throttle valve shaft and carburetor body for wear 
						

							
Chapter 3 Part B Fuel and exhaust systems (XV700-1100 models) 
3B-11

7.24 Remove the screws (1), the coasting enricher (2)

and the O-ring (3)

20 Check the carburetor body, float chamber cover and vacuum

chamber cover for cracks, distorted sealing surfaces and other

damage. If any defects are found, replace the faulty component,

although replacement of the entire carburetor will probably be

necessary (check with your parts supplier for the availability of

separate components).

21 Check the diaphragm for splits, holes and general deterioration.

Holding it up to a light will help to reveal problems of this nature.

22 Insert the vacuum piston in the carburetor body and see that it

moves up-and-down smoothly. Check the surface of the piston,for

wear. If its worn excessively or doesnt move smoothly in the bore,

replace the carburetor.

23 Operate the throttle shaft to make sure the throttle butterfly valve

opens and closes smoothly (see illustration). If it doesnt, replace the

carburetor.

24 If youre working on a 1986 or 1987 XV1100, remove the coasting

enricher diaphragm and check it for tears or brittleness (see

illustration). Replace it if its condition is in doubt. 
25 Check the floats for damage. This will usually be apparent by the

presence of fuel inside one of the floats. If the floats are damaged, they

must be replaced.

26 Check the needle valve for wear or damage (see illustration). If

theres a pronounced groove around the tip of the valve, replace it.

27 Check the needle valve seat for wear or damage (see

illustration). Check the filter cap for clogging and clean or replace it as

necessary. The sealing washer should be replaced whenever the

needle valve seat is removed.

Cleaning

Caution: Use only a petroleum based solvent for carburetor cleaning.

Dont use caustic cleaners.

28 Submerge the metal components in the solvent for approximately

thirty minutes (or longer, if the directions recommend it).

29 After the carburetor has soaked long enough for the cleaner to

loosen and dissolve most of the varnish and other deposits, use a

brush to remove the stubborn deposits. Rinse it again, then dry it with

compressed air. Blow out all of the fuel and air passages in the main

body. Caution: A/ever clean the jets or passages with a piece of wire or

a drill bit, as they will be enlarged, causing the fuel and air metering

rates to be upset

Reassembly

Refer to illustration 7.30

Caution: When installing the jets, be careful not to over-tighten them -

theyre made of soft material and can strip or shear easily.

Note: When reassembling the carburetors, be sure to use the new O-

rings, gaskets and other parts supplied in the rebuild kit.

30 Assembly is the reverse of the disassembly steps, with the

following additions.

a) Be sure the needle jet is pushed all the way into its bore. When

you install the vacuum piston, be sure the jet needle fits into the

needle jet.

b) Align the protrusion on the vacuum piston and diaphragm with the

notch in the carburetor body (see illustration).

c) Install the carburetors (see Section 6) and check the fuel level (see

Section 8).

1988 and later US models

Disassembly

Refer to illustration 7.31

31 Remove the carburetors from the machine as described in

Section 6. Set the assembly on a clean working surface. Note: Work

on one carburetor at a time to avoid getting parts mixed up (see

illustration). The throttle valves, vacuum pistons and choke plungers

can be removed and inspected without separating the carburetors.

7.26 Check the needle valve for

wear at the tip 
7.27 Check the needle valve seat for

wear; check the filter cap for clogging

or tears; replace the sealing washer

with a new one 
7.30 Position the diaphragm tab

in the notch 
						

							
3B-12 
Chapter 3 Part B Fuel and exhaust systems (XV700-1100 models)

7.31 Carburetor (1987 and later US models)

- exploded view

1 Jet needle

2 Vacuum piston

3 Needle jet

4 Pilot air jet no. 1

5 Pilot air jet no. 2

6 Coasting enricher assembly

7 Main jet

8 Pilot jet

9 Float

10 Needle valve and seat

11 Throttle stop screw

12 Synchronizing screw

13 Choke plunger

14 Pilot screw

15 Spring

16 Choke plunger cap

17 Sealing washer

18 Main jet

19 Throttle pulley

20 Bottom bracket

21 Float chamber

22 Gasket

23 Drain screw

24 Float pivot pin

25 Vacuum piston spring

26 Vacuum chamber cover

27 Top bracket

28 Choke link

32 Remove the screws and detach the top bracket.

33 Disconnect the choke link that fits between the choke shafts.

34 Carefully note how theyre assembled, then remove the synchro-

nizing screw and spring. Remove the nut and lockwasher from their

locations on the throttle shaft next to the synchronizing screw and

spring.

35 Remove its mounting screws and detach the throttle shaft

assembly. Carefully note how they fit together, then detach the throttle

levers and collar and separate the carburetors.

36 Working on one carburetor, remove the lever and washer at the

end of the choke shaft, then remove the choke shaft and spring from

the carburetor.

37 Remove the choke plunger nut, then remove the spring and

choke plunger from the carburetor.

38 Remove the vacuum chamber cover screws. Carefully lift off the

cover, taking care not to tear the diaphragm.

39 Remove the spring and the diaphragm, together with the vacuum

piston.

40 Unscrew pilot air jet no. 1 from its bore underneath the diaphragm.

41 Remove the screws and detach the coasting enricher valve from

the carburetor. Remove the large spring, diaphragm, holder, pusftrod

and small spring from the coasting enricher housing.

42 Unscrew pilot air jet no. 2 from its bore in the coasting enricher

housing.

43 Remove the float chamber cover screws, then detach the cover

and gasket.

44 Push out the float pivot pin with a small-diameter punch (2 mm)

and remove the floats.

45 Remove the screw and take out the needle valve seat.

46 Unscrew and remove the pilot jet and the main jet together with

its washer. Remove the needle jet. 
Inspection

47 Remove the spring seat from inside the piston, then remove the

clip, ring and jet needle. Check the jet needle for straightness by rolling

it on a flat surface (such as a piece of glass). Replace it if its bent or if

the tip is worn. Check the jet needle and the needle jet for wear where

they contact each other and replace them if theyre worn. Make sure

the small holes in the needle jet are clear.

48 Check the operation of the choke plunger. If it doesnt move

smoothly, replace it, along with the return spring. Inspect the needle on

the end of the choke plunger and replace it if its worn.

49 Check the carburetor body, float chamber coverand vacuum

chamber cover for cracks, distorted sealing surfaces and other

damage. If any defects are found, replace the faulty component,

although replacement of the entire carburetor will probably be

necessary (check with your parts supplier for the availability of

separate components).

50 Check the diaphragm for splits, holes and general deterioration.

Holding it up to a light will help to reveal problems of this nature.

51 Insert the vacuum piston in the carburetor body and see that it

moves up-and-down smoothly. Check the surface of the piston for

wear. If its worn excessively or doesnt move smoothly in the bore,

replace the carburetor.

52 Operate the throttle shaft to make sure the throttle butterfly valve

opens and closes smoothly. If it doesnt, replace the carburetor.

53 Check the coasting enricher diaphragm for tears or brittleness.

Replace it if its condition is in doubt.

54 Check the floats for damage. This will usually be apparent by the

presence of fuel inside one of the floats. If the floats are damaged, they

must be replaced.

55 Check the needle valve for wear or damage (see illustration 7.26).

If theres a pronounced groove around the tip of the valve, replace it. 
						

							
Chapter 3 Part B Fuel and exhaust systems (XV700-1100 models)

3B-13

56 Check the needle valve seat for wear or damage. Check the filter

cap for clogging and clean or replace it as necessary. The sealing

washer should be replaced whenever the needle valve seat is removed.

Cleaning

57 Perform Steps 28 and 29 above to clean the carburetor

components.

Reassembly

Caution: When installing the jets, be careful not to over-tighten them -

theyre made of soft material and can strip or shear easily.

Note: When reassembling the carburetors, be sure to use the new O-

rings, gaskets and other parts supplied in the rebuild kit.

58 Assembly is the reverse of the disassembly steps, with the

following additions.

a) Be sure the needle jet is pushed all the way into its bore. When

you install the vacuum piston, be sure the jet needle fits into the

needle jet.

b) Align the protrusion on the vacuum piston and diaphragm with the

notch in the carburetor body.

c) Install the carburetors (see Section 6) and check the fuel level (see

Section 8).

8 Carburetors - fuel level adjustment

Refer to illustration 8.3

Warning: Gasoline (petrol) is extremely flammable, so take extra

precautions when you work on any part of the fuel system. Dont smoke

or allow open flames or bare light bulbs near the work area, and dont

work in a garage where a natural gas-type appliance (such as a water

heater or clothes dryer) is present. If you spill any fuel on your skin,

rinse it off immediately with soap and water. When you perform any

kind of work on the fuel system, wear safety glasses and have a fire

extinguisher suitable for class B type fires (flammable liquids) on hand.

1 Support the bike securely in an upright position so it cant be

knocked over during this procedure.

2 Remove components as necessary for access to the float

chamber drain screws.

3 Attach Yamaha service tool no. YM-01312 (UK part no. 90890-

01312) to the drain fitting on the bottom of one of the carburetor float

chambers (both will be checked) (see illustration). This is a clear plastic

tube graduated in millimeters. An alternative is to use a length of clear

plastic tubing and an accurate ruler. Hold the graduated tube (or the free

end of the clear plastic tube) vertically against the float chamber cover.

4 Unscrew the drain screw at the bottom of the float chamber a

couple of turns, then start the engine and let it idle - fuel will flow into

the tube. Wait for the fuel level to stabilize, then note how far the fuel

level is below the line on the float chamber cover. 
8.3 A gauge like this or a clear tube and ruler can be

used to measure fuel level

5 Measure the distance between the indicator line and the top of

the fuel level in the tube or gauge. This distance is the fuel level - write

it down on a piece of paper, tighten the drain screw, then move on to

the other carburetor and check it the same way.

6 Compare your fuel level readings to the value listed in this

Chapters Specifications. If the fuel level in either carburetor is not

correct, remove the float chamber cover and bend the tang up or down

as necessary, then recheck the fuel level.

9 Throttle cables and grip - removal, installation and

adjustment

Refer to illustrations 9.1, 9.3a and 9.3b

Removal

1 Loosen the throttle cable(s) with the adjusters and remove the

throttle cable securing screw at the handlebar (see illustration).

2 Remove the handlebar switch mounting screws. Separate the

halves of the handlebar switch and detach the throttle cable(s) from the

throttle grip pulley (see Chapter 8).

3 Detach the throttle cables from the throttle pulley at the

carburetors (see illustrations). Remove the cables, noting how they

are routed.

4 Slide the throttle grip off the handlebar.

9.1 Loosen the cable locknuts (A) and

turn the adjusters to create slack;

remove the cable securing screw (B) 
9.3a Pull the cable housing out of the

bracket and slip the cable through

the slot (arrow)... 
9.3b ... then align the cable with the slot

in the throttle pulley fitting and

slip the cable end out 
						

							
3B-14

Chapter 3 Part B Fuel and exhaust systems (XV700-1100 models)

10.1 Loosen the screw and detach the

cable housing from the bracket 
10.2 Remove the screw (arrow) and

detach the choke lever 
11.2 Remove the nuts that secure the

flange plate to the cylinder head

Installation

5 Clean the handlebar and apply a light coat of multi-purpose

grease.

6 Route the cable(s) into place, following the same route noted on

removal. Make sure they dont interfere with any other components

11.3a Exhaust system (1981 through 1983 shaft drive models)

exploded view

1 Rear cylinder pipe

2 Gasket

3 Front cylinder pipe

4 Muffler/silencer pipe

5 Gasket

6 Clamp

7 Bolt

8 Washer

9 Sealing ring 
10. Flange plate

11 Nut

12 Bolt

13 Bolt

14 Bolt

15 Washer

16 Washer

17 Rubber damper

18 Rubber damper 
and arent kinked or bent sharply.

7 Lubricate the ends of the accelerator cable (and decelerator cable

if equipped) with multi-purpose grease and connect them to the

throttle pulleys at the carburetors and at the throttle grip.

Adjustment

8 Follow the procedure outlined in Chapter 1, Throttle operation/grip

freeplay - check and adjustment, to adjust the cables.

9 Turn the handlebars back and forth to make sure the cables dont

cause the steering to bind. With the engine idling, turn the handlebars

back and forth and make sure idle speed doesnt change. If it does,

find and fix the cause before riding the motorcycle.

10 Choke cable - removal and installation

Refer to illustrations 10.1 and 10.2

1 Remove the choke cable bracket at the carburetors (see

illustration). Align the cable with the slot in the lever and remove it

from the lever.

2 Remove the choke lever securing screw at the handlebar (see

illustration). Remove the lever and disconnect the choke cable from

the pulley.

3 Installation is the reverse of the removal steps.

11 Exhaust system - removal and installation

Removal

Refer to illustrations 11.2, 11.3a, 11.3b and 11.3c

1 Support the bike securely so it cant be knocked over during this

procedure.

2 Remove the nuts that secure the front exhaust pipe to the cylinder

head (see illustration).

3 Support the exhaust system so it cant fall and remove the

mounting fasteners (see illustrations). Lower the exhaust system

away from the bike and take it out.

4 Installation is the reverse of removal, with the following additions:

a) Use new gaskets at the cylinder head.

b) Tighten all fasteners to the torque settings listed in this Chapters

Specifications.

12 Fuel pump - circuit check and fuel pump test

Refer to illustration 12.2

1 With the engine kill switch in the On position, the fuel pump

should start and run for approximately five seconds after the ignition is 
						

							
Chapter 3 Part B Fuel and exhaust systems (XV700-1100 models)

3B-15

11.3b Exhaust system (1981 through 1983 chain

drive models) - exploded view

1 Rear cylinder pipe

2 Bolt

3 Washer

4 Gasket

5 Washer

6 Bolt

7 . Left muffler/silencer

8 Mounting bracket

9 Bolt

10 Lockwasher

11 Right muffler/silencer

12 Mounting bracket

13 Bolt

14 Lockwasher

15 Gasket

16 Clamp

17 Bolt

18 Washer

19 Washer

20 Bolt

21 Front cylinder pipe

22 Bolt

23 Lockwasher

24 Washer

25 Sealing ring

26 Nut

27 Flange plate

28 Rubber damper

29 Rubber damper

11.3c Exhaust system (1984 and later

models) - exploded view

1 Rear cylinder pipe

2 Sealing ring

3 Front cylinder pipe

4 Muffler/silencer assembly

5 Sealing ring

6 Bolt

7 Bolt

8 Muffler/silencer

protector

9 Washers

10 Bolts

11 Covers

12 Washers

13 Flange plate

14 Ring

15 Nut

16 Nut

17 Gasket-