Haynes Yamaha Xv V Twins Manual

							
2A-26 
Chapter 2 Part A Engine, clutch and transmission (XV535 models)

12.4a Push the piston pin partway out, then grasp it and pull it the

rest of the way 
12.4b The piston pins should come out with hand pressure - if

they dont, this removal tool can be fabricated from readily

available parts

1) Bolt 5). Piston

2) Washer 6) Washer (B)

3) Pipe (A) 7) Nut(B)

4) Padding (A)

A Large enough for piston pin to fit inside

B Small enough to fit through piston pin bore

12.6 Remove the piston rings with a ring

removal and installation tool 
12.11 Check the piston pin bore and the

piston skirt for wear, and make sure the

internal holes are clear (arrows) 
12.13 Measure ring side clearance with a

feeler gauge

Inspection

Refer to illustrations 12.6, 12.11, 12.13, 12.14 and 12.15

5 Before the inspection process can be carried out, the pistons

must be cleaned and the old piston rings removed.

6 Using a piston ring installation tool, carefully remove the rings

from the pistons (see illustration). Do not nick or gouge the pistons in

the process.

7 Scrape all traces of carbon from the tops of the pistons. A hand-

held wire brush or a piece of fine emery cloth can be used once most

of the deposits have been scraped away. Do not, under any circum-

stances, use a wire brush mounted in a drill motor to remove deposits

from the pistons; the piston material is soft and will be eroded away by

the wire brush.

8 Use a piston ring groove cleaning tool to remove any carbon

deposits from the ring grooves. If a tool is not available, a piece broken

off the old ring will do the job. Be very careful to remove only the

carbon deposits. Do not remove any metal and do not nick or gouge

the sides of the ring grooves.

9 Once the deposits have been removed, clean the pistons with

solvent and dry them thoroughly. Make sure the oil return holes below

the oil ring grooves are clear.

10 If the pistons are not damaged or worn excessively and if the

cylinders are not rebored, new pistons will not be necessary. Normal

piston wear appears as even, vertical wear on the thrust surfaces of

the piston and slight looseness of the top ring in its groove. New piston 
rings, on the other hand, should always be used when an engine is

rebuilt.

11 Carefully inspect each piston for cracks around the skirt, at the

pin bosses and at the ring lands (see illustration).

12 Look for scoring and scuffing on the thrust faces of the skirt,

holes in the piston crown and burned areas at the edge of the crown. If

the skirt is scored or scuffed, the engine may have been suffering from

overheating and/or abnormal combustion, which caused excessively

high operating temperatures. The oil pump should be checked

thoroughly. A hole in the piston crown, an extreme to be sure, is an

indication that abnormal combustion (pre-ignition) was occurring.

Burned areas at the edge of the piston crown are usually evidence of

spark knock (detonation). If any of the above problems exist, the

causes must be corrected or the damage will occur again.

13 Measure the piston ring-to-groove clearance by laying a new

piston ring in the ring groove and slipping a feeler gauge in beside it

(see illustration). Check the clearance at three or four locations

around the groove. Be sure to use the correct ring for each groove;

they are different. If the clearance is greater than specified, new

pistons will have to be used when the engine is reassembled.

14 Check the piston-to-bore clearance by measuring the bore (see

Section 13) and the piston diameter. Make sure that the pistons and

cylinders are correctly matched. Measure the piston across the skirt on

the thrust faces at a 90-degree angle to the piston pin, at the distance

from the bottom of the skirt listed in this Chapters Specifications (see

illustration). Subtract the piston diameter from the bore diameter to 
						

							
Chapter 2 Part A Engine, clutch and transmission (XV535 models)

2A-27

12.14 Measure the piston diameter with a micrometer

A Specified distance from bottom of piston

B Piston diameter 
12.15 Slip the pin into the piston and try to wiggle it back-and-

forth; if its loose, replace the piston and pin

12.17a Slip the circlip into its bore with its

gap away from the removal notch in

the piston ... 
12.17b ... and push the circlip all the way

into its groove; make sure its

securely seated 
13.3 Measure ring end gap with a

feeler gauge

obtain the clearance, if it is greater than specified, the cylinders will

have to be rebored and new oversized pistons and rings installed. If

the appropriate precision measuring tools are not available, the piston-

to-cylinder clearances can be obtained, though not quite as

accurately, using feeler gauge stock. Feeler gauge stock comes in 12-

inch lengths and various thicknesses and is generally available at auto

parts stores. To check the clearance, select a feeler gauge of the same

thickness as the piston clearance listed in this Chapters Specifications

and slip it into the cylinder along with the appropriate piston. The

cylinder should be upside down and the piston must be positioned

exactly as it normally would be. Place the feeler gauge between the

piston and cylinder on one of the thrust faces (90-degrees to the piston

pin bore). The piston should slip through the cylinder (with the feeler

gauge in place) with moderate pressure. If it falls through, or slides

through easily, the clearance is excessive and a new piston will be

required. If the piston binds at the lower end of the cylinder and is

loose toward the top, the cylinder is tapered, and if tight spots are

encountered as the feeler gauge is placed at different points around

the cylinder, the cylinder is out-of-round. Repeat the procedure for the

remaining pistons and cylinders. Be sure to have the cylinders and

pistons checked by a dealer service department or a motorcycle repair

shop to confirm your findings before purchasing new parts.

15 Apply clean engine oil to the pin, insert it into the piston and

check for freeplay by rocking the pin back-and-forth (see illustration).

If the pin is loose, new pistons and pins must be installed.

16 Refer to Section 13 and install the rings on the pistons.

Installation

Refer to illustrations 12.17a and 12.17b

17 Install the pistons in their original locations with the EX marks

toward the exhaust sides. Lubricate the pins and the rod bores with 
clean engine oil. Install new circlips in the grooves in the inner sides of

the pistons (dont reuse the old circlips). Push the pins into position

from the opposite side and install new circlips. Compress the circlips

only enough for them to fit in the piston. Make sure the clips are

properly seated in the grooves (see illustrations).

13 Piston rings - installation

Refer to illustrations 13.3, 13.5, 13.9a, 13.9b, 13.11a, 13.11b, 13.12

and 13.15

1 Before installing the new piston rings, the ring end gaps must be

checked.

2 Lay out the pistons and the new ring sets so the rings will be

matched with the same piston and cylinder during the end gap

measurement procedure and engine assembly.

3 Insert the top (No. 1) ring into the bottom of the first cylinder and

square it up with the cylinder walls by pushing it in with the top c

piston (see illustration). The ring should be about one inch above the

bottom edge of the cylinder. To measure the end gap, slip a fee -

gauge between the ends of the ring and compare the measurement to

this Chapters Specifications.

4 If the gap is larger or smaller than specified, double check to

make sure that you have the correct rings before proceeding.

5 If the gap is too small, it must be enlarged or the ring ends may

come in contact with each other during engine operation, which can

cause serious damage. The end gap can be incr-

ends very carefully with a fine file (see illustration) ,.~e- z^~: :

this operation, file only from the outside in.

6 Excess end gap is not critical unless it is greater than 0.040 in. 
						

							
2A-28 
Chapter 2 Part A Engine, clutch and transmission (XV535 models)

13.5 If the end gap is too small, clamp a

file in a vise and file the ring ends (from

the outside in only) to enlarge the

gap slightly 
13.9a Install the oil ring expander first 
13.9b Installing an oil ring side rail - dont

use a ring installation tool to do this

13.11a Install the middle ring with its

identification mark up 
13.11b The top and middle rings can be

identified by their profiles

Top ring Middle ring 
13.12 The top and middle rings have

identification marks (arrows); these must

be up when the rings are installed

13.15 Arrange the ring gaps like this

1) Top compression ring 3) Oil ring upper rail

2) Oil ring lower rail . 4) Second compression ring

(1 mm). Again, double check to make sure you have the correct rings

for your engine.

7 Repeat the procedure for each ring that will be installed in the first

cylinder and for each ring in the remaining cylinder. Remember to keep

the rings, pistons and cylinders matched up.p

8 Once the ring end gaps have been checked/corrected, the rings

can be installed on the pistons. 
9 The oil control ring (lowest on the piston) is installed first. It is

composed of three separate components. Slip the expander into the

groove, then install the upper side rail (see illustrations). Do not use a

piston ring installation tool on the oil ring side rails as they may be

damaged. Instead, place one end of the side rail into the groove

between the spacer expander and the ring land. Hold it firmly in place

and slide a finger around the piston while pushing the rail into the

groove. Next, install the lower side rail in the same manner.

10 After the three oil ring components have been installed, check to

make sure that both the upper and lower side rails can be turned

smoothly in the ring groove.

11 Install the second (middle) ring next (see illustration). Do not mix

the top and middle rings. They can be identified by their profiles (see

illustration), as well as the fact that the top ring is thinner than the

middle ring.

12 To avoid breaking the ring, use a piston ring installation tool and

make sure that the identification mark is facing up (see illustration). Fit

the ring into the middle groove on the piston. Do not expand the ring

any more than is necessary to slide it into place.

13 Finally, install the top ring in the same manner. Make sure the

identifying mark is facing up.

14 Repeat the procedure for the remaining piston and rings. Be very

careful not to confuse the top and second rings.

15 Once the rings have been properly installed, stagger the end

gaps, including those of the oil ring side rails (see illustration). 
						

							
Chapter 2 Part A Engine, clutch and transmission (XV535 models) 
2A-29

14.2 Pull off the shaft and no. 1 idler gear 
14.3a Pull out the Woodruff key... 
14.3b .. .take the no. 2 idler gear off the

crankshaft...

14.3c ... and locate the washer (it may

have stuck to the back of the no. 2

idler gear) 
15.1 Remove the cotter pin, disconnect

the cable from the release lever and

loosen the locknuts 
15.2a Loosen the free-play adjuster all

the way, align its slot with the cable and

pull the cable out of the adjuster .

15.2b ... then pivot the cable out of the lever slot and lower its

end out of the lever

14 Idler gears - removal, inspection and installation

Refer to illustrations 14.2, 14.3a, 14.3b and 14.3c

1 Remove the alternator rotor and starter clutch (see Chapter 8).

2 Remove the no. 1 idler gear and its shaft (see illustration).

3 Remove the Woodruff key from the crankshaft and pull off the no.

2 idler gear (see illustrations). The washer behind the gear will fall as

its removed, so be careful not to lose it (see illustration). 
4 Check the gears for cracks, chips, or damaged teeth. Replace

them as a set if problems are found.

5 Installation is the reverse of the removal steps. Make sure the

Woodruff key is in its slot (see illustration 14.3a).

15 Clutch cable - replacement

Refer to illustrations 15.1, 15.2a and 15.2b

1 Pull out the cotter pin and remove the clevis pin from the lower

end of the clutch cable (see illustration). Loosen the locknuts and

detach the cable from the bracket on the engine.

2 Loosen the cable locknut and adjuster at the handlebar (see

illustration). Disconnect the cable from the clutch lever (see

illustration).

3 Installation is the reverse of the removal steps. Adjust the clutch

free-play (see Chapter 1).

16 Clutch and primary gears - removal, inspection and

installation

Removal

Refer to illustrations 16.2a, 16.2b, 16.2c, 16.2d, 16.3, 16.4a, 16.4b.

16.5a, 16.5b, 16.5c, 16.6a, 16.6b, 16.7a through 16.7e, 16.8, 16.9a.

16.9b, 16.10a, 16.10b, 16.11a, 16.11b, 16.11c, 16.12a and 16.12b

1 Drain the engine oil and remove the oil filter (see Chapter 1). 
						

							
2A-30 
Chapter 2 Part A Engine, clutch and transmission (XV535 models)

16.2a Loosen the cover bolts 1/4 turn at a time in a

criss-cross pattern; note that some of the bolts secure

wiring harness retainers

16.2b Separate the clutch cover from the crankcase .

16.2c ... if its difficult to remove, use the pry points at

the front... 
16.2d ... and at the rear

16.3 Remove the snap-ring (arrow) and take off the oil pump

driven gear 
16.4a Loosen the clutch spring bolts evenly

2 Loosen the right-hand crankcase cover bolts in a criss-cross

pattern, 1/4 turn at a time (see illustration). Once theyre all loose,

remove the bolts and take the cover off (see illustration). If its stuck,

pry gently at the two pry points (see illustrations). Dont pry anywhere 
else or the gasket surface may be damaged.

3 Remove the snap-ring and take off the oil pump driven gear (see

illustration).

4 Loosen the pressure plate screws evenly in a criss-cross pattern,

then remove the screws and springs (see illustrations). 
						

							
Chapter 2 Part A Engine, clutch and transmission (XV535 models)

2A-31

16.4b Clutch (XV535 models) exploded view

1) Pressure plate

2) Push plate

3) O-ring

4) Short pushrod

5) Steel ball

6) Metal plates

7) Friction plates

8) Wire circlip

9) Clutch damper plate 
10) Seat spring

11) Seat plate

12) Clutch boss

13) Retaining plate

14) Clutch housing

15) Long pushrod

16) Push lever assembly

17) Primary drive gear 
						

							
2A-32 
Chapter 2 Part A Engine, clutch and transmission (XV535 models)

16.5a Take off the pressure plate ... 
16.5b ... together with the push piece (A)

and short pushrod (B) 
16.5c The friction plates and metal plates

can be removed as a set

16.6a Pull out the steel ball with

a magnet... 
16.6b ... then pull out the long pushrod 
16.7a Bend back the lockwasher

16.7b Youll need a tool to keep the clutch hub from turning; this

is the Yamaha special tool...

1) Clutch boss nut 2) Holding tool

16.7c ... or you can make your own tool from steel strap
5 Remove the pressure plate, then take off the friction plates and

metal plates as a set (see illustrations).

6 Remove the steel ball and the long pushrod (see illustration).

7 Bend back the lockwasher on the clutch boss nut (see

illustration). Loosen the nut, using a special holding tool (Yamaha tool

no. YM-91402, part no. 90890-04086 or equivalent) to prevent the

clutch housing from turning (see illustration). An alternative to this tool

can be fabricated from some steel strap, bent at the ends and bolted

together in the middle (see illustration). You can also make a holding

tool by drilling through a steel plate and friction plate and bolting them 
together (see illustration). Slip the bolted plates into their normal

installed position to lock the clutch housing artd clutch boss together.

To keep the engine from turning, wedge a rag between the teeth of the

primary drive gear and the driven gear on the clutch housing. Once the

nut is loose, remove it (see illustration). 
						

							
Chapter 2 Part A Engine, clutch and transmission (XV535 models)

2A-33

16.7d A holding tool can also be made by

bolting an old metal plate and friction

plate together 
16.7e Remove the nut... 
16.8 ... and the lockwasher

16.9a Pull the clutch boss off... 
16.9b ... and remove the holding plate 
16.10a Bend back the

lockwasher (arrow)...

16.10b ... then wedge a rag between the

drive and driven gears to keep them from

turning and loosen the nut 
16.11a Remove the lockwasher ... 
16.11b ... the retaining plate ...

8 Remove the lockwasher and discard it (see illustration). Use a

new one during installation.

9 Remove the clutch boss and holding plate (see illustrations).

10 Bend back the lockwasher from the nut that secures the primary

drive gear (see illustration). Wedge a rag between the driven gear and 
drive gear teeth to keep the gears from turning, then loosen the nut

(see illustration). Once the nut is loose, slide the clutch

housing/driven gear off and remove the nut.

11 Remove the lockwasher, retaining plate and oil pump drive gear

(see illustrations). 
						

							
2A-34

Chapter 2 Part A Engine, clutch and transmission (XV535 models)

16.11c . . . the oil pump drive gear. .

16.12a ... the primary drive gear ...

16.12b ... and the Woodruff key

16.13a Pull one end of the wire circlip out

of its hole in the clutch boss ... 
16.13b ... and work the circlip out of

its groove 
16.13c Pull off the clutch damper plate ...

16.13d .... the seat spring ...

16.13e ... and the seat plate

16.15 Measure the clutch spring

free length

12 Remove the primary drive gear and Woodruff key (see

illustrations).

Inspection

Refer to illustrations 16.13a through 16.13e, 16.15, 16.16 and 16.17

13 If the clutch has been chattering (juddering), remove the wire ring

and the steel plate, seat spring and seat plate that make up the clutch 
damper (see illustrations). These parts need not be removed if the

clutch hasnt been chattering.

14 Examine the splines on both the inside and the outside of the

clutch boss. If any wear is evident, replace the clutch boss with a new

one.

15 Measure the free length of the clutch springs (see illustration).

Replace the springs as a set if any one of them is not within the values

listed in this Chapters Specifications. 
						

							
Chapter 2 Part A Engine, clutch and transmission (XV535 models)

2A-35

16.16 Measure the thickness of the

friction plates 
16.17 Check the metal plates for warpage 
16.28 With the nut tightened to the

specified torque, bend the lockwasher

against one of the flats

6.29 Install the oil pump driven gear and

secure it with a new snap-ring 
16.30 Install the clutch boss lockwasher

16.31 Once the nut is tightened to the

specified torque, bend the lockwasher

against the nut

16 If the lining material of the friction plates smells burnt or if its

glazed, new parts are required. If the metal clutch plates are scored or

discolored, they must be replaced with new ones. Measure the

thickness of each friction plate (see illustration) and compare the

results to this,Chapters Specifications. Replace the friction plates as a

set if any are near the wear limit.

17 Lay the metal plates, one at a time, on a perfectly flat surface

such as a piece of plate glass) and check for warpage by trying to slip

a gauge between the flat surface and the plate (see illustration). The

feeler gauge should be the same thickness as the warpage limit listed

in this Chapters Specifications. Do this at several places around the

plates circumference. If the feeler gauge can be slipped under the

plate, it is warped and should be replaced with a new one.

18 Check the tabs on the friction plates for excessive wear and

mushroomed edges. They can be cleaned up with a file if the

deformation is not severe.

19 Check the edges of the slots in the clutch housing for

indentations made by the friction plate tabs. If the indentations are

deep they can prevent clutch release, so the housing should be

replaced with a new one. If the indentations can be removed easily

with a file, the life of the housing can be prolonged to an extent.

20 Check the teeth on the primary drive gear and driven gear for

wear or damage and replace them if defects are found. The driven gear

is replaced together with the clutch housing.

21 Check the pressure plate and push plate for wear and damage.

Replace any worn or damaged parts.

22 Check the pushrods and the steel ball for wear or damage and

replace them if defects are visible. Install a new O-ring on the short

pushrod (see illustration 16.5b).

23 Check the bearing surface in the center of the clutch housing and 
replace the clutch housing if its worn or damaged.

24 Clean all traces of old gasket material from the clutch cover and

its mating surface on the crankcase.

Installation

Refer to illustrations 16.28, 16.29, 16.30, 16.31, 16.34, 16.35, 16.37a,

16.37b, 16,38a, 16.38b and 16.38c

25 Install the primary drive gear Woodruff key, then install the

primary drive gear, oil pump drive gear and retaining plate (see

illustrations 16.11b, 16.11c, 16.12a and 16.12b).

26 Install a new lockwasher on the retaining plate. Make sure the

lockwasher tabs fit into the notches in the retaining plate, then install

the nut.,

27 Coat the clutch housing bearing surface with clean engine oil,

then slip the clutch housing onto the crankshaft (see illustration

16.10a).

28 Wedge a rag between the primary drive gear and the driven gear

on the clutch housing so they cant turn, then tighten the nut to the

torque listed in this Chapters Specifications. Bend the lockwasher

against the nut to hold it (see illustration).

29 Install the oil pump driven gear and secure it with the snap-ring

(see illustration).

30 Install the clutch holding plate, then the clutch boss (see

illustrations 16.9b and 16.9a). Install a new lockwasher (see

illustration). Install the nut with its recessed side toward the clutch

boss and tighten it slightly (see illustration 16.7e).

31 • Hold the clutch boss and housing from turning with one of the

methods described in Step 7. Tighten the clutch boss nut to the torque

listed in this Chapters Specifications, then bend the lockwasher

against the nut to secure it (see illustration).