Yamaha XS650 1974-1980 Service Manual 03 motor
CHAPTER 3. ENGINE OVERHAUL
3-1.
3-2.
3-3.
ENGINE REMOVAL
A. Preparation for removal
B.
Fuel tank removal
C.
Removal of other parts.
D. Engine mounting bolts and engine removal
ENGINE DISASSEMBLY
Governor and breaker assembly removal
A.
Cylinder head and cylinder removal
B.
Rocker arm removal
C.
Valve removal
D.
Piston removal
E.
Generator removal
F.
Primary drive gear and clutch assembly removal
G.
Kick axle and change shaft removal
H.
Electric starter unit removal
I.
Oil pump removal.
J.
Crankcase disassembly
K.
Transmission illustration
L.
Shift drum removal
M.
Crank shaft removal
N.
INSPECTION AND REPAIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Cyinder head cover.
A.
Cylinderhead.....................................................2
B.
Valve, valve guide and valve seat.
C.
Valvespring....................................................
D.
Rocker arm and rocker shaft
E.
Cam shaft wear
F.
Cam chain, sprocket and dampers
G.
Cylinder.........................................................2
H.
Piston and rings
I.
Pistonpin........................................................2
J.
Crankshaft
K.
Oil pumpp
L.
Clutch
M.
Transmission
N.
Electric starter gears and clip spring
0.
Kickstarter....................................................
P.
Crankcase and oil passages
Q.
Bearings and oil seals
R.
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3-4.
ENGINE ASSEMBLY AND ADJUSTMENT
............................
A. Shift.........................................................
B. Transmission and crankshaft
C.
Shifter assembly
D.
Kick starter assembly
E.
Electric-starter gear assembly
F.
Clutch
.......................................................
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G. Generator.....................................................
H.
Oil pumpp
I. Right-hand crankcase cover
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J. Piston........................................................
K. Cylinder and cylinder head.
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L. Camshaft.....................................................
M. Cylinder head cover
N. Governor and breaker assembly
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0. Engine.......................................................
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CHAPTER 3.
ENGINE OVERHAUL
31. ENGINE REMOVAL
A. Preparation for removal
1. All dirt, mud, dust and foreign material
should be thoroughly removed from the
exterior of the engine before removal and
disassembly.
2. Place machine on center stand. Star-f
engine and allow it to warm up. Stop
engine and drain engine/transmission oil.
8. Carburetor (to the left), and throttle cable
9. Brake pedal
10. All wires and cables connecting engine
and chassis
11. Top center engine mounting brackets
(Remove only four bolts for easier re-
assembly)
B. Fuel tank removal
1. Turn fuel
“off” position
petcock on the “on” position unless the
engine is operating). Disconnect fuel pipes
and vacuum pipes from petcock.
2. Lift seat and remove fuel tank holding
bolt. Remove fuel tank.
C. Removal of other parts
Remove the following parts in the order given.
1.
Exhaust pipes
2. Horn (as a unit)
3. Both side footrests
4. Change pedal and drive chain guide
5. Left-hand crank case cover and clutch
cable.
6. Side covers
7. Air cleaner assembly and ventilation
hoses.
petcocks
to “on” (there is no
-
fuel will not flow from a
T
12. Drive chain (with special tool)
D. Engine mounting bolts and engine removal
1. Remove mounting bolts in the order as
..--
2. Remove the engine to the right.
3-2 ENGINE DISASSEMBLY
A. Governor and breaker assembly removal
Remove the following parts in the order
given.
1.
Breaker cover
Breaker backing plate
2.
3. Breaker housing
4. Governor cover
Notched plate
5.
Lock nut (using punch and hammer)
6.
7.
Governor assembly
8.
Breaker shaft (to the point side)
9. Dowel pin
10. Advance unit housing
B. Cylinder head and cylinder removal
Remove the oil delivery and pipe fitting
1.
attached to the crankcase. Note place
ment of copper gaskets.
Remove all tappet covers.
2.
Remove spark plugs.
3.
Remove four cylinder head cover holding
4.
bolts, three cylinder head holding bolts
and eight cylinder head holding nuts.
Remove the head cover. It may be nec-
5.
essary to tap each lightly with a soft
hammer.
Remove the camshaft as follows.
6.
Remove tensioner adjusting bolt to make
a.
the chain tension loose.
b. Push out the master link pins with the
cam chain cutter.
c. Tie each end of the
camchain
with a wire
to prevent it from falling into the crankcase.
7.
Remove the cylinder head and cylinder.
NOTE:
It is advisable to remove the
stator
and
rotor after finding the place of the master
link pins. Refer to item “F. Generator
removal.”
C. Rocker arm removal
Remove rocker shaft covers.
1.
Remove shouldered sleeves and O-rings.
2.
3. Withdraw rocker shafts with the special
tool or 6 mm bolt.
D. Valve removal
Compress the valve spring and then
1.
re-
move both retainer locks.
Remove the compressor and lift off the
retainer and springs.
Remove valve stem seals.
2.
Remove valves.
3.
NOTE:
Deburr any deformed valve stem end. Use
an oil stone to smooth the stem end. This
will help prevent damage to the valve
guide during valve removal.
E. Piston removal
Remove piston pin clips, piston pins and
pistons.
F. Generator removal
1. Remove the
Remove the securing nut and lock washer.
2.
stator.
3.Mount the rotor puller (special tool) onto
the rotor and pull the rotor off.
i
.’
G. Primary
~eca9coio7oj
drive gear and clutch assembly re-
moval
Remove the crankcase cover (right).
1.
Loosen the drive gear securing nut by first
2.
placing a rag folded into many layers between the teeth of gears to lock them.
Remove six clutch spring screws and pre-
3.
ssure plate.
Remove clutch plates, friction plates,
4.
push crown, two push rods and two balls.
-19-
1.
Push rod
2.
Ball
Push rod
3.
4.
Push
5.
(Aluminuml
crown
Hold the clutch unit with the holding tool
(special tool), and unscrew the clutch boss
lock nut.
H. Kick axle and change shaft removal
1. Slip the bent spring off and pull the kick
axle assembly out.
2. Remove circlip from left side of change
shaft and pull the shaft out.
I. Electric starter unit removal
Remove the gear train cover, and idle gear
1.
1 and 2.
1. Kick axle 4. Kick gear 7. Spacer
Holder 5.
2.
Clip 6.Shim
3.
Kickclip
8.Kickspring
9.Spring
10. Washer
11.Circlip
wide
2. Remove the four mounting bolts and
motor.
3. Remove the
(6). shaft 2
4. Remove the circlip
sembly
panhead
(5),
and gear 1 (4).
(7) (8)
(9).
screw
(11),
and gear
(10),
gear 2
as-
5. Starter gears illustration
D
T
g
Y
3
J. Oil pump removal
1. Remove the tachometer drive gear, oil
pump driven gear, and key.
2. Remove the three Phillips screws.
3. Remove the pump unit.
-
20
2. 1.
Absorber Idlegear
3.
ldlegear
4.Gear 1
5.Shaft 2
6.Gear 2
1
2
6. 7.
Gear Starter 3 wheel
9.Gear 4
Panhead
10.
11.TCirclip
screw
K.Crankcase disassembly
1. Loosen all case securing bolts and nuts
l/4 turn at a time to avoid case
warpage,
and remove them.
2. Use a soft rubber hammer to carefully
separate the crankcases.
-
L. Transmission illustration
1.
Main
axle
2. 2nd pinion gear (17T)
3. 3rd pinion gear
4. 4th pinion gear (21T)
5. 5th pinion gear
6. Drive sprocket (17T)
(13T)
(20T)
(23T)
1’ 1st wheel gear
2’ 2nd wheel gear
3’ 3rd wheel gear
4’ 4th wheel gear
5’ 5th wheel gear
(32T)
(27T)
(26T)
(23T)
(22T)
Transmission
M. Shift drum removal
1.
Bolt
2. Lock plate
3. stopper
4. Shaft bolt
5. stopper
Stopper spring
6.
7. Shift
8.
9. Shift fork
10. Shift fork
cam
Bearing
Plate
(3)
(2)
11. Shiftfork (1)
Pin
12.
13. Cotter pin
14. Guide bar
15. Cam stopper
16. Stopper spring
17.
Gasket
18. Stopper bolt
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