MOTO GUZZI 850 Le Mans III Instruction manual

~)(LeMans)
(HEE)
WORKSHOP MANUAL
COD. 289201 51
Additions to the Workshop manual for the models V1000 G50 and 1000 SP -Code 17920161

The illustrations and descriptions in this booklet are indicative only and the manufacturer reserves Itself
the right to introduce any modification it may deem necessary for better performance or for constructive
or commercial reasons without prior notice.
SEIMM MOTO GUZZI- TECHNICAL PUBLICATIONS
CODE 28 92 01 51
1000K - 1-82 -Printed in Italy - Tecnopress/Bergamo

~ __________________________________________________________________ ~ 22 8
HINTS ON THE PROPER USE OF THIS MOTORCYCLE
Due to its exceptionally high feature, this motor-
cycle can be considered as in the racing ma-
chine class and as such has to be ridden in a
sportsmanlike way. For this very reason, it has
met the favour of many motorcycle fans but,
same asforall racing bikes,it hasto be used ac-
cordingly .
Forinstance,
forfuel feed this model isfitted with
carburettors with pumps and if the twist grip is
not used correctly in accordance with the en-
gine revolutions, there might be
an excess of
fuel which is ejected bythe carburettors, ending
in the air filter box of the carburettors same.
When travelling at lowspeed
or in otherwordsat
low revs,
it is necessaryforthe throttle gripto be
used with care since the immission of a greater
quantity of fuel mi
ght not be fully absorbed by
the engine.
At high speed, also in case
of abrupt accelera-
tions, the fuel is entirely absorbed and used up
bythe engine,thuseliminatingthis riskand
con-
ferring to this model the brilliant « kicking up»
qualities that make it one
of its outstanding fea-
tures.
175

INDEX
Cylinders
Pistons
Con-rods
Crankshaft
Carburettors
Float levelling
Replacing the air filter
Front fork lubrication
Oil pneumatic shock absorbers

II MAIN FEATURES
ENGINE
-cylinder disposition
-bore
-stroke
-displacement
-compression ratio
-max torque
VALVE GEARING
CARBURATION
LUBRICATION
GENERATOR ALTERNATOR
IGNITION
-ignition data
-contact breaker points gap
-spark plugs
-plug points gap
-ignition coils
STARTING
TRANSMISSIONS
CLUTCH
PRIMARY DRIVE
GEARBOX
-gear ratios:
Low gear
2nd gear
3rd gear
4th gear
5th gear
SECONDARY DRIVE
-ratio
-overall gear ratios
(engine-wheel)
Low gear
2nd gear
3rd gear
4th gear
5th gear
twin cylinder -4-stroke
«V,. 90°
83 mm
78 mm
844 cc
9.8 to 1
7.6 kgm at 6200 rpm
O. H.V., push rod operated
n. 2 carburettors <c Dell'Orto,. type PHF 36 B (D) (right)
PHF 36 B (S) (left)
pressure, by gear pump
wire gauze and cartridge filters in oil sump
normal lubrication pressure 3.8 to 4.2 kg/sq cm
(pressure relief control valve in the sump)
oil pressure sender unit in the crankcase
fitted in the front part of the crankshaft (14 V - 20 A)
coil-battery ignition with double contact breaker
and automatic advance with centrifugal masses
ignition advance (fixed) 8°
automatic advance 26°
full advance (f. + a.) 34°
0.37...;... 0.43 mm
Bosch W 5 D
Lodge 2 HLNY
0.6 mm
n. 2 fitted on the frame
electric starter (12V - 0.7 KW) with electromagnetic
ratchet control ring gear bolted on the flywheel
starter button (START) fitted on the R/H side of handlebar
twin driven plates, dry type
fitted on the flywheel side
hand controlled by lever on left handlebar
by gears, ratio 1 to 1.235 (2 = 17/21)
5 speeds, frontal engagement, constant mesh gears.
Cush drive incorporated
pedal operated on the UH side of the bike
1 to 2 (2 = 14/28)
1 to 1.388 (2 = 18/25)
1 to 1.047 (2=21/22)
1 to 0.869 (2 = 23/20)
1 to 0.750 (2 = 28/21)
by cardan shaft, bevel gear set
1 to 4. 714 (2 = 7/33)
1 to 11.643
1 to 8.080
1 to 6.095
1 to 5.059
1 to 4.366
177

FRAME
SUSPENSIONS
-front
-rear
WHEELS
-front
-rear
TIRES
-front
-rear
BRAKES
-front
-rear
DIMENSIONS AND WEIGHTS
-wheel base (loaded)
-max length
-max width
-max height
-min. ground clearance
-dry weight abt
PERFORMANCES
-top speed
-fuel consumption
FUEL AND OIL CAPACITIES
duplex cradle, tubular structure
telescopic fork «MOTO GUZZI patent»
with oil pneumatic shock absorbers
swinging fork and rear dampers with adjustable external
springs concentric to the oil pneumatic shock absorbers
light alloy castings with rims:
WM 3/2.15 x 18" CP2
WM 3/2.15 x 18" CP2
100/90 V 18
110/90 V 18
disc type with caliper having 2 cylinders, controlled
by hand lever on the RIH side of the handlebar
hydraulic transmission independent from the rear brake:
disc dia. 300
mm
braking cylinder dia. 38 mm
master cylinder dia 12.7 mm
disc type with fixed caliper with two cylinders
foot controlled with pedal on the RIH side of the bike:
disc dia. 242 mm
braking cylinder dia. 38 mm
master cylinder dia. 15.875 mm
the rear brake is connected by an hydraulic
transmission to a second brake on the front wheel
having the same features and size as the hand
controlled front brake
1.505 m
2.190 m
0.640 m
1.160 m
0.175 m
206 kg
230 km/h (144 mph), solo
5.7 I x 100 km
-fuel tank 25 I (6.15
US gls) supergrade petrol (98/100 NO-RM)
(reserve 3 I about) (3.1/4 quarts)
-oil sump 3 I (3.1/4 quarts) oil
"Agip SINT 2000 SAE 10 W/50 ..
-gear box 0.750 I (1.3/4 pints) oil "Agip F.1 Rotra MP SAE 90»
-rear drive box
(bevel gear set lubrication)
-front fork (each leg)
-braking circuits
(front and rear)
178
0.250 I (9 oz abt) oil of which: 0.230 I (8.1/4 oz abt)
«Agip F.1 Rotra MP SAE 90» and 0.020 I (3/4 oz)
«Agip Rocol ASO/R» or Molikote "A» type
0.060 I (2 oz abt) fluid "Agip F.1 ATF Dexron»
fluid «Agip F.1 Brake fluid -SAE J 1703 B"

......
-....j
CO
• SERVICE SCHEDULE
ITEMS
MILEAGE 900 mi. 1800 mi. 3700 mi. 5600 mi. 7500 mi. 9400
mi .
COVERED ~
1500 km 3000 km 6000 km 9000 km
12,000 km 15,000 km
T
• Engine oil R R R R R R
1-- ._ -
._-- --
----
-_. _ --
---- -- -- -
• Oil filter cartridge R R
1- ..
- _._ .. _-
_._- - ----
-.
• Wire gauze oil filter C C
• Air filter C R C
--
- .. •. ----
--- - --
. _----
-.--
• Ignition timing A A A A A A
--
-_ .. _-
• Spark plugs A A A R A A
• Rocker clearance A A A A A A
-
• Carburetion A A A A A A
-- ---- -.
_- _. _-- --_ ._-
----
-- - --
• Nuts and bolts A A
• Fuel tank, filters and pipes C C
---- --_. ----.---
-----
----_.
Gear box oil A A A R A A
- --
---- ---- ----
Rear drive box oil A A A R A A
1-----
-- - -- ----
------
--
Wheel and steering bearings .
--. -- ---.-
Fork legs oil
Starter motor and generator
-A A A A A R
Brake systems fluid --
--
. __ ._-
----
I--- .
Brake pads A A A
A = Inpections -Adjustments -Possible replacements -Servicing I C = Cleanings I R = Replacements.
• Operation required for maintaining the vehicle according to emission regulations (USA).
A A
Occasionally. check the electrolyte level In ballery , lubricate joint. and cables; every 500 km (300 mile.) check the engine oil level.
In any case, renew this oil at least once a year .
A -
11,300 mi. 13,200 mi. 15,100 mi. 17,000 mi. 18,900 mi.
18,000 km
21 ,000 km
24,000 km 27,000 km
30,000 km
R R R R R
---- -----
-- ---
I---
R
C
R R
-- --
A A A A A
R A A R A
A A A A A
A A A A A
----- 1-----
A
C
R A A R A
-_ .
R A A R A
A
R
A
A A A A R
-- --
A A A A A
-
-"-
-
-_ .. _- -- ---
----

lEI ENGINE OVERHAULING AND CHECKING
229~ ____________________________________________ ~
180

CYLINDERS
SELECTION OF CYLINDER DIAMETER
GRADING A GRADING B GRADING C
83.000 + 83.006 mm
83.006..;- 83.012 mm
83.012";-83.018 mm
3.2677 +3.2679"
3.2679..;-3.2681 " 3.2681
+3 . 2684"
PISTONS
SELECTION OF PISTON DIAMETER
GRADING A GRADING B GRADING C
82.968 + 82.974 mm 82.974+ 82.980 mm 82.980";-82. 986 mm
3.2664 + 3.2666" 3.2666..;- 3.2669" 3.2669
+3.2671"
The pistons of an engine must be balanced; a
weight difference between them of 1.5
gr is al-
lowed.
N.B. -The above selection values are valid for
the model 850 Le Mans" starting from
engine
n. 80390.
When fitting a piston check that the class mark
stamped on the piston and the word
"seA»
(exhaust) are facing the exhaust hole in the cy-
linder.
4.02 .;.- 4. 04
o 22.000.;.- 22.006
Values in mm
3.990.;.-3.978
~:J'~2+'.54 ~
o 22.000.;.-22.004
o 83
0.30 .;.- 0.45 1.490
.;.- 1.478
n
II
1.490 .;.- 1.478
-JL
0.25.;.-0.40
59.984'.;.-59.970
~ ______________________________________________________________ ~230
181

CON-RODS
22 025 -'- 22.045
139.975
-;-. 140.025
Max parallelism and complanarity
difference between both axis measured
at a distance of 200 mm ± 0.10
-
~ l0.'\.'-'
_I I
o?4
.......
rx
~
,..
:_", L...
I
I~ -_-- __ -------'~\
~
4.6 -+ 4.8 Kgm
Values in mm
231~ ____________________________ ~
CRANKSHAFT
Crankpin diameter:
STANDARD PRODUCTION PIN
44 .008 ..;... 44.020 mm
1.7326 ..;... 1.7331"
0.254 mm / .010"
43.754";'" 43.766 mm
1.7225..;... 1.7230"
Mainshaft diameter, timing side:
STANDARD PRODUCTION PIN
0.2 mm / .007S"
37.975 ..;... 37.959 mm
37.775..;... 37.759 mm
1.4951 ..;...1.4944" 1.4872
..;... 1.4866"
182
23 . 800 -+ 23 . 850
+
t!
...
r-~
+
e
C")
...
n u
too:
~L-_~~~
~ "\: 0-.'\. "
Y
2.3.800 -;-. 23.600
25.064
-;-. 25.097
¢ 22.020 -+ 22.041
AFTER PRESSING IN COD·RoD
BRING IT TO A DIA. OF
22.025 ..... 22.045
IToTAL THICKNESS I
IISTEEL ..... ANTI FR. I 1.535 ..... 1.544J
1 '--'
23 . 800 -+ 23 . 850
CLASSES
CLASS "A ..
BLUE DOT
ON STEM
47.130 -+- 47.136
Values in mm
CLASS " B ..
WHITE DOT
ON STEM
47 . 136 -+- 47 . 142
~ ____________________________ ~232
UNDERSIZED OF
0.50S mm / . 020 " 0.762 mm / . 030 "
43.500..;... 43.512 mm
43.246 ..;... 43.258 mm
1.7120 ";"'1.7130" 1.7025
..;... 1.7030"
UNDERSIZED OF
0.4 mm / .01574" 0.6 mm / .02362"
37.575 ..;... 37.559 mm
37 . 375 ..;... 37 . 359 mm
1.4793 ..;... 1.4787" 1.4715 ";"'1.4707"

Mainshaft diameter, drive side:
STANDARD PRODUCTION PIN
0.2 mm I .0078"
53.970 ...... 53.951 mm
53.770 ...... 53 . 751 mm
2.1248 ...... 2.1240" 2.1169
...... 2.1162"
CHECKING CRANKSHAFT BALANCING
To balance statically the crankshaft it is neces-
sary
to add a weight of 1.650 ...... 1.652 kg.
-~
! f ~
...
Values in mm
SHIM CLEARANCE
0.150+0.300
37.975.;.-37.959
ClASS -A- Cl!SS -B-
BLUE MARK MUTE MARK
ON SHOULDER ON SHOULDER
FLYWHEEL SIDE FLYWHEEL SIDE
44.008+«.014 «.014+«.020
UNDERSIZED OF
0.4 mm I .01574" 0.6 mm I .02362"
53.570 ...... 53.551 mm 53.370 ...... 53.351 mm
2.1090 ...... 2.1083" 2.1011 ...... 2.1004"
44.008.;.- 44 . 020
53.970.;.-53.951
~ ____________________________________________________________ ~233
183

234
18,5
17,5
235~ ____________________________ ~
184
II CARBURATION
CARBURETTORS
N, 2 Oell'Orto type carburettors « PHF 36 8 (0))
(right) « PHF 36 8 (S)" (left)
Controls
• throttle control grip on the R/H side of the
handlebar;
• easy starter lever for cold engine starts on the
UH side of crankcase.
«A" starting position for cold engine.
«8» riding position.
Standard
carburettor settings:
Choke ¢ 36 mm
Throttle valve 60/3
Atomizer 265 A 8
Main
jet 115
Idling jet 50
Starter jet 70
Pump
jet 33
Needle K 18 (3'd notch)
Float 10 gr
Idling screw adjustment: opens 1 1/2 turns
FLOAT LEVELLING
To level the floats place the carburettor in verti-
cal position as shown in fig. 235.
N.B. -Contrary to what said in the workshop
manual code 149201 56 the above values are
valid also for model 850 Le Mans II.

\ \ \
--====-- ~~
________ -238
185

237
REPLACING THE AIR FILTER
Every 6000 km (3700 miles) checkconditions of
airfilter, if necessary clean it using compressed
air; it is advisable to replace it every 9000 km
(5600 miles).
To replace the air filter lift the saddle, remove
fuel tank and side covers. Take out R/H
carbu-
rettor and undothe screwsfixing the airintake to
the bike frame:remove the two side screws and
take out from the
R/H side the container "A"
complete with the air filter.
238L- __________________________________________________________ ~
186

mEl SUSPENSIONS
FRONT FORK LUBRICATION
To replace the oil in the front fork legs, proceed
as follows:
• with the bike on the central stand, loosen the
side screw
"en locking the steering head to the
fork arm; disconnect compensating pipe and
completely unscrew the hexagonal screw plug
«8,,; then undo drain plug
"A ,, ;
• slightly press the front part of the bike to
force out the plug « 8 " which is solidal to the
shock absorber. Do this paying attention not to
damage the instruments panel;
• refit plug "
A" and introduce the quantity of
fluid necessary (60 cc Agip F. 1 ATF Dexron)
through the space existing between the inner
diameter of the fork and the shock absorber
body ;
• release the front part of the bike refit pl ug
«8" and lock the side screw. Repeat the same
operation for the other fork leg;
• reconnect compensating pipe and check
the pressures keeping to the given values.
OIL PNEUMATIC SHOCK ABSORBERS
The operating load pressures of these shock
ab~orbers are the following;
• front: 2
...;... 3 kg/sqcm
• rear: 3 ...;... 5 kg/sqcm
To check the pressure it is advisable to use a
pressure gauge having a very short pipe (better
ifany),as the capacity ofthe pipe may affectthe
pressure existing inside the shock absorbers.
To ascertain to which extent
your pressure
gauge reduces, when taking the measurement,
the pressure insidethe
shock absorber itis suf-
ficient to carry out two consecutive measure-
ments: the difference between the two readings
gives approximately the pressure reduction
oc-
curing whenever a measurement is taken.
The measurement must be taken with the bike
on the central stand and with cold shock
ab-
sorbers; to charge the shock absorbers only
use moistureless air.
N.B. -Pressures gauges as above, are found on
the market: however it can be necessaryto place
a supplementarygasketin the gaugehead, in or-
der thatthe valve stem inside the shock absorber
will be pressedonlywhen the gaskethas made a
perfect tightening.
239
Before modification
rModificati on
~ ____________________________ ~ 240
187

'"
,..:
0
V
t:
Q)
C.
0
ON I
1+
OJ
~ I
t:
'0.
E
:::J
.0
~ I
E
~ I
E
EO
'"
+
~ f
Q)
>
~
E
I-
E
'"
eci
0'>
;!
~
a;
>
~
I-
241 _________ .,---_J
L..- __________ J 242
188

mSWINGING FORK
2~m
Vo'
tt--
jh'
I I ~
!7
"
----I
~
l ~ 1I.r-
___ J
G--
~
~
<=
~
~
~t
~
--
E 136.
0007136.100 mm
23
E mm
10
~
~
E
E
0
111
(J')
..r
co
-I-
0
111
0
111
co
~
~
135.2007135.100 mm
KITS SUPPLIED ON REQUEST
The following kits remain valid:
• GEARBOX SET OF STRAIGHT TOOTHED
GEARS
foreseen
in the workshop for the model 850 Le
Mans II -code 149201 56.
410mm
If ~
~
bI
40,5 mm
39. 992739 .967 mm
E
I E
g l ~
0
co
0
cxi10
....
........
oi N
....
(')
-1- '-
+ 0
0 0
0 N
<0 oi
I ~
65.C00765 . ~00 mm
gj\
....
EN
61 .991 + 61 .961 mm \ \
E'-
r~
0 N
VI\
10
I,-----v-
(J')
..r
co
-I-
..)
~
0
. ~
10
f \
i\~
""
I~
L \
I~
"1
I
18.150718 .050. mm 39.9927 9 .9~7 n:lm
60 .000~p~. 100 mm 140.5 m 243
189

190
• ELECTRICAL WIRING DIAGRAM
1 Parking light, front (4 W)
2 Hight beam bulb (45 W)
3 Low beam bulb (40 W)
4
3-way connector for headlight (AMP)
54-way connector Molex
6
15-way connector
7
12-way connector
8 Ignition key
(3 positions)
9 Voltmeter
(3 W)
10 Tachometer (3 W)
11 Rev-counter (3 W)
12 Warning ligh t, right turn signal (j.2 W)
15 Warning light, parking (1 .2 W)
16 Warning light, high beam (1.2 W)
17 Warning light, brake fluid level (1 .2 W)
18 Warning li ght, oil pressure (1.2 W)
19 Warning light, generator (1.2 W)
20 Warning light, neutral position (1 .2 W)
21 Warning light, left turn signal (1 .2 W)
22 Switch for simultaneous turning on of all flashers
23 Turn flasher, front, right (21 W)
24 Turn flasher, front, left (21 W)
25 Turn flasher, rear, right (21 W)
26 Turn flasher, rear, left (21 W)
27 Engine starting and stop button
28 Flashing light, turn signals, and horn switch
29 Horn
30 Front brake switch (STOP)
31 Rear brake switch (STOP)
32 Flashing light relay (FLASH)
33 Rectifier
35 Alternator (14 V - 20 A 21)
35 Regulator
36 Battery
37 Starter motor relay
38 Starter motor
39 Terminal block with fuses (16 A)
40 Taillight
41 Rear stop light (21 W)
42 Number plate and rear parking light (5 W)
43 3-way connector
44 Flasher box
45 Oil brake level solenoid
46 Neutral position solenoid
47 Oil pressure solenoid
48 Coils
49 Spark plugs
50 Contact breaker