MOTO GUZZI V-7 700 User manual

700
CC
OPERATING HANDBOOK
FOR
STRIPPING, CHECKING AND
ASSEMBLING OPERATIONS

SEIMM
SOCIETA ESERC1ZIO INDUSTRIE MOTO MECCANICHE S.p_A. _ ... =~ ~ ... __
Clpilale 1OOe, 1 1. solloocr iUo' l. &'5 .000.00II ~. _
Sode IIO" Ie ' Milano
Galle rl. d. Cri.tclo, I. , J • To l<l lo"o _5
Oirezlone e Stablllman\l; 22054 Mandello d~1 lario (Co)
Telelono: 71112 (4 linee ur bane )
Telegrammi: SEIMM MANOELLOLAAIO
V-7 700
MOTO GUZZI
cc.
OPERATING HANDBOOK
FOR STRIPPING , CHECKING AND
ASSEMBLING OPERATIONS
1 sl EOITION

I NTROOUCTION
The purpose of this handbovk is to supply the necessary instructions '0\
carrying out overhauls and repairs in a rational way.
The data provided here are meant to give a general knowledge about the
maln checking operations to be carried out when overhauling the different
groups.
The handbook is provided with illustrations, drawings and diagrams neces-
sary to carry out stripping, checking and assembling operations.
This handbook will also be a
guidance for those who wish to know the
manufacturi ng characterist i cs of the parts in concern. The knowledge of
such ch aracteristics by repairing personnel will be an essential factor for
performing a good job.
NOTE · The terms .. RIGHT HAND ., and (( LEFT HAND " used In the text
are
to be considered as seen from the rider astri de the saddle.

I II DE X
Pog.
MAIN FEATURES. 5
TOOLS FOR OVERHAULING 9
DESCRIPTION OF ENGINE 10
REMOVAL OF ... ENGINE-GEARBOX .. GROUP
FROM FRAME .
11
ENGINE OVERHAUL 12
Stripping of engine 12
ROCKER BOX COVERS CYLINDER HEADS
VALVES -GUIDES -SPRINGS. 16
Stripping 16
Removal of springs and valves. 16
Inspection and overhaul of cylinder heads. 16
Inspection and overhaul of valve guides 16
Valves-valve guides coupling data . 17
Inspection and overhaul of valve seats in cy-
linder heads 17
Inspection of valves 18
Inspection of valve springs. 18
Valves sealing
lest. 18
Assembling
of cylinder heads on cylinders 19
CYLINDERS -PISTONS -PISTON RINGS AND
Oil SCRAPERS 20
Cylinders wear check 20
Selection of
cylinders diameter 20
Pistons 21
Selection of piston diameter 22
Piston rings and 011 scrapers 22
Piston rings and scrapers-piston slots height
clearance 22
Piston ring and oil scrapers clearance . 22
Fitting of piston pins 22
CON -RODS -CRANKSHAFT -MAIN BEARING, 23
Flywheel side -MAIN BEARING, Timing side
Con-rods 23
Thickness 01 big end bearings . 23
Diameter of crankshaft pin 23
Small end bushing . 24
Checking weights for engine balancing 24
Checking paraUelism of end axis. 25
Fitting up con-rods on crankshaft . 25
Crankshaft . 27
Diameter of main journal, flywheel side 28
Diameter of main journal, timing side . 28
I/O of main bearing, flywheel side . 28
I/O of main bearing. timing side 28
Flywheel side flange complete with main bea-
ring , 29
Seal ring
for flywheel side flange . ']9
Timing side flange c/w main bearing 29
Timing cover 29
Timing cover seal ring 29
Crankcase . 29
Inspection and overhaul of crankcase. 30
Wear check of tappet guides In crankcase 30
SUMMING UP OF DATA PERTAINING TO CRANK
MECHANISM PARTS 31
TIMING DATA 32
Camshaft 32
Diameter of crankshaft bearings and their hou-
sings on crankcase 32
Checks 32
Tappets 33
Coupling data of tappets and tappet guides in
Pa u·
crankcase 33
Push rods 33
Rockers 34
Coupling data of rocker arms and splindles 34
Tappet clearance adjustment . 34
Valve timing 34
SUMMING UP OF DATA PERTAINING TO
TIMING PARTS 37
ENGINE LUBRICATION 38
Description 38
Oit pump 38
Inspection and checks 38
Oit cleaner 39
Oit piping 40
011 pressure solenoid 40
Oit breather 40
Oit pressure gauge 40
ENGINE ASSEMBLING 41
ENGINE FEEDING 43
Fuel tank 43
Air cleaner on carburetors 44
Carburetors 44
Standard carburetor settings 45
Idling speed adjustment 45
Top speed adjustment and main jet selection
Stripping of carburetor 046
Servicing of carburetor 46
ENGINE BRAKE TEST 48
CLUTCH 49
Removal of clutch assembly 49
Checking clutch springs 49
Checking pressure plate 50
Checking driven plates 50
Checking intermediate plate 50
Checking s1arting ring gear 50
Clutch assembling operation 50
Clutch control 50
Checking clutch control 50
Checking clutch operating lever on gearbox 50
Outer body 50
Cage c/w balls 50
Inner body 50
Pressure rod 50
Pressure rod cap 51
Outer body seal ring 51
Clutch adjustment . 51
GEAR BOX 52
Gear box description 52
Gear box control 52
Gear box stripping 53
Gear box 55
Gear box cover 55
Check and overhaul of the gear box unit parts 56
Gear box and cover 5&
Seal rings 55
Ball bearings and roller bearings .55
Mainshaft 56
Layshaft 5~
Fitting clearance between gear bushings and
layshafl 56
Layshaft gears .
.50
Fitting clearance between bushings and gears
on layshaft
5~
Sliding muff 57
Clutch shaft 57
3

Pog_
Clutch shelt seal ring 51
Inner body 57
Cush drive Shaft semi-collar 51
Cush drive plate 57
Cush drive spring 57
Sl iding sleeve 57
Idle geer 57
Gear selector drum 57
Preselector shalt , with sector gear 57
Preselector shall return spring 57
Gearshllt operating lever _ 57
Gear selector forks and fork shalls 57
Assembling 01 gear box 58
REAR WHEEL DR IV E _ 59
DescrlpUon _ _ y;
Stripping 01 rear wheet drive 59
Check and overhaul of rear wheel drive as-
sembly
&J
Rear wheel drive box 60
Drive box Ilange 60
Distance shims _ _ 60
Internal toothed sleeve for rear wheel coupling
Bevel gear set 60
Cage retaIning ring 60
Rear wneel - drive box distance piece 60
Bear ing housing 60
Adjusllng washers 61
Sh ims 61
Bevel gear distance piece 61
Lockring safety washer 61
Lockring 61
Seal rings _ 61
Drive shalt-bevel pinion sleeve 61
Dri ve shalt 61
Double Joint 61
M_ ~
Rubber gaiters 61
8ali bearings and taper roller bearings 61
Assembling 01 rear wheel drive _ _ 61
Assembling rear wheel drive 10 RlH arm of rear
fork _ _ _ _ _ _
62
Contact check and adjustment 01 bevel gear
teeth
63
REAR SUSPENSION 65
Stripping from Irame 65
Check and overhaul 65
Flexible bushings 65
Fitting up on frame 65
FRONT SUSPENSION AND STEERING 66
Str ipping Of tetescopic front fork and steering 60
Overhaul 01 tetescoplc front fork and steering 67
Fork rods 67
Top bushings _ 67
Bottom bushings 67
Fork bottom covers 67
Fork springs 68
Spnng housings 68
Top plug rubber r ings 68
Top plug seals 68
Steering taper roller bearings 68
Steering adjusting lockrings 68
Steering tube _ 68
Assembling fork and steering on Irame lug 68
STRIPPING OF REAR SWINGtNG FORK
Overhaul of re ar fork
70
70
70
70
70
71
71
Nuls and locknuts
Support spindles
Seals
8all bear ings and taper roller beerings
Fi
tting up rear lark
WHEELS AND BRAKES
Front wheet
•
Rear wheel
Wheels and brakes check
Wheels
Rims
Spokes
Brake linings
72
72
72
73
73
7.
7.
7'
Brake springs
Brake cam_
Brake pins
Brake drums
Rear wheel central
body
Hub seals
Tapper
roller bearing housings
Tapper roller bearings
AdJusling weshers
Brake cam lever
Front brake cable
Front brake adjustment
Rear brake adjustment
Assembling 01 wheels
Assembling of fronl wheel hub
Fitting front
wheelan lark
Assembling rear wheel hub
Fitting rear wheel on fork and drive
box
TAPER ROLLER 8EARINGS AND BALL
BEARINGS
FRAME
Check and overhaul
Rear fender and 1001 boxes
Center and side stand return springs
Crashbar
Rear brake
conlrol lever, spindle and rod
Alder and pillion fcotrests
Assemb!ing
ELECTRICAL EQUIPMENT
BATTERY
Features
Inspection and maintenance
Cleaning
Check and smearing
01 terminal blocks
Electrolyte level
Charge
ch eck
Common battery faults
GENERATOR
Descr iption
Operati on
Regulator unit
Testing data _ _ _
Adlustmenl of generator belt tension
Generator faults
STARTER MOTOR
Description _
Operatlcn
Testing data
Slarler molar faults
IGNITION SYSTEM
General inlormation
Coil
Distributor
Automatic spark advance device
Contact breaker
Condensor
Distributor
cap and rotor
Spark plugs
Ignition timing
Ignition faults
Pall_
74
7.
7.
74
"
"
74
74
74
"
75
75
75
75
75
76
76
76
n
78
78
78
78
78
78
78
78
79
79
79
79
79
79
79
'"
81
83
83
B3
83
86
87
88
94
9'
95
W
99
103
103
103
10<
10<
105
105
105
105
106
100
ELECTRIC HORN 113
Overhaul and repair In struction 113
Tesllng data II ..
Electric horn laults _ 115
LIGHTING 117
Head light 117
instruments panel 117
Tal! light and stop
light 117
Fuses 117
INSTRUMENTS AND CONTROLS 118
Wiring diagram legend 119
LUBRICATION AND GENERAL MAINTENANCE
CHAAT 121

MAIN FEATURES
ENGINE
Cycle
Number of cylinders
Cylinder disposition
80"
Stroke
Displacement
Compression ratio
Revs
at max engine speed
Output at max engine
speed
Crankcase
Cylinders
Cylinder heads
Crankshaft
Crankshaft
supports
Connecting rods
Pistons
Va lve gear
4 strokes
2
.. V ~ _90 o
80 mm . (3 .149 ")
: 70 mm . (2 .755")
703.717 cc. (42.93 cu . in.)
9 to 1
6000 r.p.m.
50 HP SAE
in 1i9ht alloy
light alloy barrels with hard
chrome
linings
: in light allo y, hemispherical,
with
specia l cast iron inserted
valve
seals
: steel construction
: of anti-friction material pressed
in suitable housing (as used in
all F1 Race car s)
steel construction with AL-TIN
alloy thin
wall bearings
: in light alloy
O.H.V., push rod operated via the camshaft
In the crankcase
and
gear driven by the crankshaft.
Inlet:
-opens 24 ° before TOC
- c:oses sa n aller BOC
Exhaust:
-opens
sa o alter BOC
-closes 22 " after TOe
Rccker clearance for valve liming :
-0,5 mm. (.0196")
Normal rocker clearance (cold engine):
-inlet
0.1 mm. (. OO393 ")
-exhaust 0.2 mm. (.00787")
Carb uratlon
Both ca rb uretors are gravity fed from the tank.
Carburetor Make:
type Oell'Orto 5.
5.1. (right and lell)
La;brificatlon
Pressure, by
gear pump driven by the crankshaft.
Oil strainer in crankcase .
Ncrmal lubricating pressure 2.5 - 3 kgs.lsq. cm. (35.6 _ 42. 7
Ibs/sq.ln.)
(Controlled by relief valve)
Electrfcally controlled oil pressure gauge.
Cooling
By ai
r. Cylinder and cylinder heads deeply finned.
Ignition
By battery with automatic advance Marelll distri
butor type
5 123 A.
Initial advance: 10 °.
Automatic advance: 2So .
Ignition
liming 38° full advance.
Contact breaker gap: 0.42.0.48 mm. (.016-.018").
Spark plug: n. 225 in Bosch-Marelll scale or eQuivalent.
Plugs point gap : 0,6 mm. (.023").
Ignition coil : Marelli BE 220 D.
Starter molar
Marelli slarter MT 40 H (12 V - .7 HP) with electromagneti c
ratchet control. Ring
gear boiled on flywheel.
Exhaust system
Dual exhaust pipes and mufflers.
TRANSMISSION
C: ut ch
Twin driven plates, dry type. located on the lIywheel. Con-
trolled by lever on left
handlebar .
Gear box
Four speeds,
fr onta l engagement. Constant mesh gears
Cush drive spring i ncorpora ted.
Separate case bolted on crankcase, operated by rocker
pedal on the right hand side of the machine.
Engine-gearbox ratio: 1 to 1.373 (16-22)
Internal gear ratios:
-
Low gear
-Second
gear
-Third gear
-High gear
Secondary dri ve at rear wheel
to 1.933
to 1.
263
to 0.954
to 0. 754
(15-29)
(19-24)
(22-21 )
(24-18)
By constant speed
homokinet ic double
Bevel layshalt gear-wheel ratio; l
oint cardan shal l
4.625 (8-37)
Overall gear ratios:
Low gear
Second gear
Third gear
High gear
1 to 12292
1 to 8.031
1 to 6.066
1 to 4]94
FR.f,ME
Duplex cradle, tUbular struclure.
~us pen slon
Rear swinging fork with external adjustable springs .
Telescopic front fork incorporating hydraulic dampers.
Telescopic front fork with external adjustable spring .
Wheels: 18x3 spoked steel rims, front and re ar .
Wheels: 18x3 spoked steel rims.
front and rear.
Tires
4. 00 x 18 front and rear, block type .. high speed _.
Front tire pressure
Solo rider
1,5 kgms/SQ.
With pillion
om . 21 P. S.1.
5

Rear tire
Solo rider 1.8 kgmslsq. cm . = 25 P.S.I.
Wilh pillon 2.0 kgms /sq. cm . = 28 P.S.!.
Note -The above reeommendation is lor normal riding (crui·
sing speed). !I using Ihe maehlne al eonslanl high speed or
on motorway s !he above pressures should be Increased by
0.2 kgms/sq . cm. (2,8 P.S.I.).
Bntkes
Twin lead ing shoes exp anding type Ironl brake . operate d by
hand lever on the r ight handlebar.
Large rear brake operated by pedal on lell hand sioe of
mac hine .
Overall dlmen tlons and weight
- Wheelba~e
- Lenglh
- W idth
- Height (dry)
- M
in imum ground clearance
- Curb weigh!
6
1.445 mls . (ab t. 56.9 ")
2.230 mls. (abl. 87.5" )
0.
795 miS. (abt. 31.2")
1. 0SO miS. (abt. 41.2"')
O.
ISO mets. (abl. 5. 9")
243 kgs 536 Lbs
Performance
Maximum permissi ble speed and gradients climbab le in
each gear. solo ri ding.
L ew gear 66 Kms/h (41 m.p.h.) Clmblng ability 60%
Seco nd gear 96 kms/h (59.6 m.p.h.) Cli mbing abili-
ty 34%
Tl> ird gear 120 kms/ h (74.5 m.p.h.) Climbing abil i-
ty '<:3 '/0
High gear 170 kms/ h (106 m.p.h.) Climbing ability 14l/a
Capacities
Fuel tank: 20 liters (5.28 US gla.) inc lud ing aboul 4 liters
reserve (about 1 USA gl) -Petrol 98 /100 No (Regular oclane)
Sump 3 1I1ers (3 '1 . Quarts) Shen Multigrade 20/40 _ Trans-
mission 0.750 liters (1 ~/. Pln!s) Shell Spirex 90 E. P. -Rear
wheel drive 0.300 liters (5/8 Pints) Shell Splrax 90 E. P. -
Front lor k dampers 0.160 liters = 5,4 oz USA ~ Shell Tel-
lux 33 -.

Fig. 1 - lelt view
Fig. 2 -RighI view
7

TOOLS REQUIRED FOR STRIPPING, CHECKING AND REASSEMBLING
(see Fig. 3)
Fig. No. Order No.
1 12904700
2 12906900
3 60910500
4 12909500
5 12905400
6 12912700
7 60907200
8 12913700
9 12913100
10 12907000
11 12912600
12 12912000
13 12903000
14
12910700
15 32906302
16 12911801
17 26907800
18 12907100
19 12913600
20 12912900
21 12906500
22 12908300
23 12905900
24 12905300
25 12913600
1-IJ 2~ 3~4
8~ 9~ 10~
5
14
12
~
Description
Puller for taper bearing races on rear fork .
Pu l ler for roller bearing race in drive box.
Steering top linking plate puller.
Front fork rods assembling tool.
Wrench for removal of Jayshaft lockring .
L ockring adjusting tool for rear dampers.
Valve dismantling and assembling tool.
Puller for layshaft ball bearing in transmission box .
Puller for mainshaft roller bearing in transmission box.
Puller for mainshaft and clutch shaft bearings in transmission box
cover.
Special wrench for front fork lockring.
Flange assembling and oil seal locating tool on crankshaft, flywheel
side.
Tool for resr fork taper roller bearing adjustment.
Bush
for oil seal fitting on mainshaft.
Oil pump gear puller .
Flywheel and clut ch unit holding tool.
Piston pin puller .
layshaft and rear drive bevel holding tool.
Tool for removing the flange c/w bearing. flywheel side.
Special tool to check positioning marks on timing gears.
Clutch dismantling and assembling tool.
Tool for timing cover assembling and oil seal locating on crankshaft.
timing side.
Tool
for removal of clutch shaft.
Tool for holding crankshaft when removing bevel nut.
Tool for transfer of pOSitioning marks on timing gear .
Y
~+
~
19
6 7
~22
~ 25
24
~
@
~15
17
~'6
.21
18
rJ23
1
Fig. 3
.
l'
I
9

DESCRIPTION OF ENGINE
(see Fig. 4 & 5)
The" V7» model is equipped with a twin-cylin-
der 90 ' V engine. Cylinders have light alloy bar-
rels with hard crame lining s and are deeply
finned for cooling .
Cylinder bottoms fit into suitab le housings in
crankcase.
Crankcase in ligllt alloy, provided with six bolts
(four long, two short) to secure cylinders and
cylinder heads.
Cylinder heads are in light alloy, with special
cast iron inserted valve seats.
Rocker box covers in light alloy. Steel construc-
t io n crankshaft on two special tin-aluminium alloy
main bearings, pressed in suitable housings.
Steel construction con-rods with thin wall bear-
ings at big ends and bronze bushes at small
ends.
Piston in light alloy. with 4 rings: 3 over pin (t wo
piston rings and one oil scraper) and 1 belo w
pin (oil scraper),
O.H.V. valve gear, operated through camshaft,
tappets, push rods and rockers. Camshaft gear
driven by crankshaft . Carburetors are gravity fed.
Pressure lubrication from oil sump through gear
Fig. 5
10
.:.
, '\'(r~'
";'~
:Y·!~
-
. '.
.. ' ,',
, .. , ~
.. ' .. ,
'j: ••••••
~~ .. ~ .... ~
, \. '".
""': '.
..
Fig. "
pump driven by crankshaft. Oit recovery by gra-
vity. Wire gauze type oil cleaner in crankcase .
Lubr ic ation pressure co ntrol led by relief valve.
Breather tube conveys oil vapors Into breather
box from which, after condensation. oil returns
into sump.
Pressure
is di scharged outside through vent
tube . Engine is air cooled . Cylinders and cylinder
heads are suitably finned.
Ignition by battery, coil and distributor operated
by crankshaft through built-in gear .
Ele
ctric starting, electrically controlled.

REMOVAL OF "ENGINE·GEARBOX» GROUP FROM FRAME
(see Fig.
6)
For the removal of the .. engine·gearbox,. group
from frame" remove the following:
battery covers (U H & RlH) and disconne ct
cab les from battery .
speedo control cable from transmission in
gearbox.
saddle, fuel tank and battery, after removal of
holder bracket.
throttle and air cables two-ways adapter,
without disconnecting cables.
battery support plate, clutch control cable
from lever on gearbox, starter control electric
cables and neutral indicator cable from gear-
box.
coil, after disconnnecting electric cables; dis-
tributor cap, after disconnecting spark plugs
cables; distributor rotor.
generator covers; generator belt guard and
generator unit.
mufflers,
large band on rubber gaiters.
Put engine on a support and after unscrewing
nuts extract bolts securing «engine·gearbox»
group to frame; move the group forward (towards
front wheel) tilting it to the right then extracting
it from frame.
N.B.: The above
operation is suggested to be
carried out by two mechanicians.
After removal of group from frame, wash same
with petrol and dry by compressed air. Then
strip engine assy from gearbox assy.
11

ENGINE OVERHAUL
ENGINE STRIPPING
To strip remove the following:
12
drain oil from sump by unscrewing oil drain
plug (see B on Fig. 7).
remove spark plugs.
ignition distributor unit c/w support, after
unscrewing bolts securing same to crankcase
and removing gasket.
generator securing band, after removal 01
cotter pins and pins.
generator support bracket , after unscrewing
bolts securing same to crankcase.
clutch unit , unscrewing bolts securing starter
ring gear by means of ring wrench and tool
No. 12911801 (see 16 on Fig. 8). Bear in mind
that such bolts must be unscrewed in crossed
sequence. After removal of ring
gear remove
Jj ..
Fig . 7
Fig. a
n. S. clutch plate, intermediate plate, 1.5. clutch
plate, pressure plate, washer and springs .
-
generator driving pulley, after unscrewing nut
on crankshaft by means of ring wrench and
tool No. 12911801.
-
timing cover, after unscrewing bolts securing
same
to crankcase.

seal ring from timing cover.
cam wheel, removing nut securing same to
camshaft, by means
of ring wrench and tool
No. 12911801 (see 16 on Fig. 9) .
oil pump gear , by means of 1001 No. 12911801
(see 16 on Fig. 10) and oil pump gear puller
No. 32906302 (see 15 on Fig. 10).
distribution gear.
flywheel. After flattening the lock plates, un-
screw bolts securing flywheel to crankshaft,
by means of
box wrench and tool No.
12911801 (see 16 on Fig. 11).
cylinder head lubrication oil pipe.
"
rocker cover screws, then remove covers and :;
gaskets.
-
rocker spindle bolts and washers.
--16
Fig. 11
Fig. 10
..
13

rocker arm spindles, rocker arms, rocker arm
springs and washers (see Fig. 12). Remove
tappet adjusting screws
after loosening nuts.
push rods.
rocker arms support, after unscrewing the four
long bolts and the two short bolts (each head)
which secure cylinder and cylinder head to
crankcase .
cylinder heads c/w valves and remove gasket.
Using tool No. 60907200 (see 7 on Fig.
13) re-
move from
cylinder head the semlcones, top
collars, springs, bottom collars and then ex-
tract valves from inside.
cylinders and relative gasket.
tappets from housing on crankcase .
piston pin, by means
of puller No. 26907800
(see 17 on Fig. 14),
after removal of circlips.
the piston and from same remove piston rings.
oil sump, after unscrewing screws securing
same to crankcase . Also remove oil sump
gasket.
oil pump, after removing screws securing sa-
me to crankcase. From pump remove key,
driven
gear and driving shaft.
Fig. 12
Fig. 13
complete oil cleaner and gasket (see B on
Fig.
15) . Cleaner consists of : 2 retaining bolts,
bottom plate, wire gauze and cleaner body.
oil pipe (see A on Fig. 15), after flattening
lo ck plates and unscrewing securing bolts
and washers. Remove from pipe the pressure
r ",! ief valve, consisting of : pl unger , spring ,
b
ott om plate and plug.
con-rod caps,
after flattening lock plates and
unscrewing nuts. Then extract con-rods from
Fig. 14

top of crankcase. Remove half bearings from
con-rods.
camshaft,
after unscrewing bolts securing
flange
to crankcase.
flange c/w
crankshaft bushing, timing side,
after flattening lo ck plates and unscrewing
bo lts securing flange to crankcase.
flange c/w main bearing, flywheel side, after
flattening
lock plates and unscrewing bolts
securing flange
to crankcase. Then, by means
of tool No. 12913600 (see 19 on Fig. 16) remo-
ve flange c/w main bearing from crankcase.
crankshaft.
oil pressure solenoid.
oil
filler plug (see A on Fig. 7).
After the above operations the crankcase is
com-
pletely stripped, except for the long and short
bolts.
N.B.:
Du ri ng stripping it is strongly recommend-
ed
to keep well apart the two .. cylinder-
rod-piston .. groups.
To remove timing cover
without removing engine
from frame, it is necessary to proceed as
follows :
-after removing belt cover and generator belt.
unscrew
the three bolts securing pulley as-
sembly. Extract pulley
outer flange and
washers.
using the three bolts previously securing pul-
ley, fit tool No. 12905300 on pulley hub (see
24 on Fig. 17) and thus holding crankshaft ,
unscrew crankshaft nut
by means of a ring
wrench.
unscrew the three bolts and remove special
tool,
inner body of pulley and pulley hub .
block or support engine.
remove bottom frame/engine stud.
remove screws securing timing
cover Ie
crankcase.
Fig. 15
Fig. 16
Fig. 17
15

ROCKER BOX COVERS -CYLIN-
DER HEADS -VALVES -GUIDES
-SPRINGS
Cylinder heads, in light alloy,are finned to increa-
se coo ling surface. Long bolts, short bolts and
nuts secure cylinder heads to crankcase.
STRIPPING
Removal and stripping of cylinder heads are re-
quired when loss of compression is noticed, such
loss being imputable to defective valve sealing,
and also after a certain period of operation, in
order to remove carbon deposits in combustion
c hamber.
When engine is on frame, cylinder heads strip-
ping Is carried Qut as follows:
Disconnect:
-sparks cables.
- air inlet tubes and carburetors .
-exhaust pipes and muffler s.
- distributor cap.
-
rocker box covers.
- rocker arms and rocker arms supports.
Then remove cy linder head s.
No difficulties are involved in strippi ng down cy·
linde r heads into parts. In any case all stripping,
overhaulfng and assembling operations, and re·
quired tools, are lIsted in the following para·
graphs:
REMOVAL OF SPRINGS AND VALVES
PositIon cylinder head on tool No. 60907200 (see
7 on Fig.
13) and with the arm of same press on
the valve top collar so to remove semicones,
top
co llar , spring, bottom plate and, from inside cy-
linder head, the valve.
INSPECTION AND OVERHAUL
OF CYLINDER HEADS
Using a chamfered scraper and a wire brush re-
move carbon deposits and Inspect valve seats.
INSPECTION AND OVERHAUL
OF VALVE GUIDES
Valve guides are pressed in their housings in
cylinder heads. Removal and refitting are car-
ried out by means of a round punch (see Fig. 18
& 19). Valve guide must be replaced in case of
excessive lash between its hole and the valve
stem, whenever such lash
is not eliminable by
simply replacing valve.
After pressing guide in housing, hole must be
reamed
wit h a straight reamer in order to bring
same
to size as shown In coupling data chart.
Negative
allowance in pressing guides in their
housings on cylinder heads, for both inlet and
exhaust valves. is
to be comprised between
mm. 0.046 and 0.075 (.0018 - .(0295).
16
•
f
r
fi t
•
Fig. 18
Fig. 19
Fig. 1 9/ 1

VALVES-VALVE GUIDES COUPLING DATA
Valve guide
I.D.
Inlel valve
8.000 + 8.022 mm.
Exhaust valve {.3149 - .3158"}
INSPECTION AND OVERHAUL OF VALVE
SEATS IN CYLINDER HEADS
In order to obtain a perfect match with valves,
valve seats must be regrinded. Angles of inclina-
tion of the seats are as fo llows:
inlet valve:
60
0
25 '
-exhaust valve: 45 ° 25'
38
38 .6
38.4
7.987
7. 972
Valve sl em
Clearances
di
ameter
7.972 + 7.987
rnm. 0.013 -+ 0.050 mm .
(.3138 -.3144") (.0005 -.0019")
7.965 -+ 7.980 mm.
0.020 ~ 0.057 mm.
(.3136 - .3142") (.0008 -.0022 ")
Regrinding is carried out by means of a milling
cutter, guided by a stem inserted in valve guide .
After milling, in order to obtain a perfect match ,
it is necessary to grind the valve in its seat with
emery paste. Should valve seats be so deterio-
rated that normal milling will not be sufficient,
replacement of same will then be required.
Fig. 20
7.980
7965
8. 000
.022
14 . 064
14 . 075
34.6
34.4
34
17

INSPECTION OF VALVES
Check valves integrity and existing lash between
stem and guide (for clearance refer to coupling
data chart and Fig. 20) . To regrind valves, insert
valve stem In self-centering chuck of Universal
Grinder (see Fig. 21) and adjust chuck swivel
table so that valve will have an angle of inclina-
tion as follows:
-exhaust valve: 4S
e
25 ' + 1~'
- inlet valve:
SO U 25 ' o
+ 15'
After grinding check thickness of valve head at
max. dia. to be not Jess than 0.8 mm. (.0315").
Sho uld surface at stem end show any defor-
mation. regrind same on grinding wheel (see
Fig. 22).
18
Whenever regrinding valve seats, it is advisable
to check that valve springs are compressed bet-
ween 37 mm. and 38 mm. (1.456 -1.496"). Adjust
by adopting suitable washers at bottom collar ,
between spring and cylin de r head.
INSPECTION OF VALVE SPRINGS
Check that valve springs are not c racked and
have not lost their elasticity.
Spring, compressed at 37 mm. (1.456"), must
o
show a load of Kg. 33 + 2 (72 Ibs -12 ozsl
(closed valve position).
Spring, compressed at 28 mm. (1 .024"), must
o
show a load of Kg. 60 + 2 (132 Ibs - 4 ozs)
(open valve position).
Springs flexibility can be checked by suitable
apparatus (see Fig. 23). As to load and deforma-
tion data refer to Fig. 24 .
VALVE SEALING TEST
After reassembling valves on cylinder head, fill
up inlet and exhaust ducts with gasoline. Losse s.
if any, will be detected by liquid leaking in com-
bustion chamber.
Fi g. 23