Ducati 750 Sport Bevel Heaven User manual

Servicing
~UCATæ
Motor Cycles
750 SPORT/GT
860
Published by TRACTOR & MECHANICAL PUBLICATIONS PTY. L TO.
for !!!u~~ 55-57 Hume SÚeet, Crows Nest, N.S.W.
Telephone: [phone]
and at 405 Pitt Street,'Sydney, N.S.W., Australia
Telephone: [phone]
Telegrams & Cables: "Cycleserv" Sydriey
Publishers of Automotive & Motor Cycle books

Publ ished October, 1975
Copyright (Q TRACTOR & MECHAN ICAL PUB L1CA TIONS PTY. LTD. - 1975
Cecil R. Dodd - Cremorne, N.S.W., Australia.
Registered at the National Library Canberra, A.C. T., Australia.
ISBN No. 0 86889 032 4
All rights reserved. No part of this publications may be reproduced, stored in a reÚieval system, or transmitted in
any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior
written permission of Tractor & Mechanical Publications Pty. Ltd.
No liability can be accepted for any inaccuracies or omissions in this publication, although every reasonable care
has been taken to make it as complete and accurate as possible.
Published by arrangement with and special thanks to
NORM FRASER PTY. L TO., 137 Lambton Road, Broadmeadow, N.S.W.,
Australia,
distributors of Oucati Motorcycles.
Produced by TRACTOR & MECHANICAL PUBLICATIONS PTY. LTD.
for !!~!~ 55-57 Hume Street, Crows Nest, N.S.W.
Telephone: [phone]
and at 405 Pitt Street, Sydney, N.S.W., Australia
Telephone: [phone]
Telegrams & Cables "Cycleserv" Sydney
Publishers of Automotive & Motor Cycle books

DUCA TI
-750 GT/SPORT -860
CONTENTS
Specifications-750 ............................. 1
Electrical Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
i-6wtocheck Ignition Aävance ........ ... ... ... . ..5
Specifications-860 .............................7
Maintenance 750 and 860 . . . . . . . . . . . . . . . . . . . . . . . . .8
Care of Battery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Locating and Remedying Faults.............. ... . .12
Disassembling and Re-assembling Engine. . . . . . . . . .15
Electronic Ignition -860 . . . . . . . . . . . . . . . . . . . . . . . . .57
Wiring Diagram -750 GT . . . . . . . . . . . . . . . . . . . . . . . .63
Wiring Diagram-750Sport..................... .65
Wiring Diagram-860 .......................... .67
Exploded Engine-860 ......................... .69

SPECIFICATIONS-750
Engine
Two cylinder four stroke "L" configuration
Four stroke twin cylinder 90 degree longitudinal "L" configuration, supported in a cradle frame.
Bore: 80mm (3.1496")
Stroke: 74.4mm (2.9291")
Cylinder capacity: 748cc (45.629 cu. in.)
Compression ratio: 8.5:1
Deeply finned cylinders in light alloy with special cast iron liners inserted. Connecting rods in
special steel, with roller cage at the big end and the small end bushed to take the gudgeon
pin;Light alloy pistons, press forged with the skirt in one piece and three piston rings, one of
which is an oil scraper. Cast light alloy cylinder head, closely finned with inserted valve seats.
Timing
The timing system is provided with overhead valves, inclined at 800, timed by an overhead
camshaft. The valves are made of special steel.
SUCTION COMPRESSION WORKINGSTROKE EXHAUST
~ i .
""~'" V
"--._ _ -
With a valve/rocker clearance of 0.10mm (0.0039") for both inlet and exhaust the timing is as
follows: Inlet opens 650 before T.D.C. and closes 84° after B.D.C.; Exhaust opens 74° before
B.O.C. and closes 580 after T.O.C.
The tappets are adjusted by means shims on the end of the valve stems, and the clearance
should be checked after the timing has been set and with the engine cold.
The timing gears in the crankshaft and on the cam shaft are provided with reference marks
and care should be taken to re-align these when assembling the engine after repair or
maintenance.
Fig. 1
TImIng
.', ~?(ô\~ I
., m;,,~.¥~
..1. .~.~..~ ~.
:"i!.:~:~i§.i~~ :r
_ "~l~ " t'4:~~"
." ". ~L. ~~. ;Zlli~ . .tl' ~ ':~~
,.. .... I ....,.' . ,.' ,..d.'="l
-"'ø S/y" -¡~ 6;:'otr. (:\"';0"-
. ~r0~" -co~!f':;~;~~irx.
.~ \'1I"";~ . \.\~1~~'g
~\:~~"J:;;~~Jl.. .
..~t~.. ~_~'~-=Y~.'
""~,.,\_.,,::_~
i. '." '-. r=-
'-.,!".~",
r- '.
_J ,J '.'¡¡. if I
, ./'
~~:~ . Fig. 2

2
IDLING ADJUSTMENT
THROTTLE
ADJUSTM ENT
Fig.3
Fig. 4
ADJUSTMENT DF
MINIMUM AIR INTAKE
Fig. 5
+-
Fuel
Petrol is gravity fed to the engine through two Amal carburettors wiJh air filters. The tank holds
17 Iitres (3.74 gallons) and has two three-position cocks: close-open-reserve. The reserve is
about 1.6 Iitres íO.35 gallons)
Lubrication
The engine is pressure lubricated by means of a gear pump driven by the crankshaft. This pump
takes the oil from the lowest point in the crankcase, through a filter and forces it through a
series of oilways to all parts of the engine requiring lubrication. The oil return is by gravity.
The sump capacity is about 4.5 Kg (1.10 gallons) and an oil filter with dipstick and sealing
gasket allows easy oil level measurement.
The filer plug dipstick is marked with two notches to indicate lowest and highest permissible
levels and the level is checked by resting the plug on the filer.
The system is quite simple and requires no special maintenance other than topping up the oil
every 500 Km (300 miles) and changing the oil and cleaning the filter every 2,000 Km
(1,200 miles).
Cooling
The engine is air cooled by means of fins on both the cylinder barrel and cylinder head.
Ignition
Ignition is by battery and coil with 100 advance when the engine is stopped and 290 automatic
advance at over 1,200 r.p.m., a total of 380.
To time the ignition see the figure on page 6. The clearance between the platinum plated
contacts should be 0.3 to OAmm (0.0118" to 0.0157") and should be checked with a feeler
gauge.
The spark plugs are Lodge 3 H N or a similar model and are located on the left side of the
cylinder head.
When replacing the plugs make sure the plug is aligned correctly in the thread so as to avoid
cross threading. Screw the plug in lightly at first, then tighten it.

3
Running-in Precautions 750
During the first 1000 Km (620 miles) the rev counter should not exceed 4,500-5,00 r.p.m. and
do not maintain the maximum allowed speed through the gears for long periods. '
After the first 500 Km (300 miles) and after the first 1 ,00 Km (600 miles) with the engine stil
warm, change the crankcase oil, adjust the tappets, fitting the appropriate rocker shim and
check the cylinder-head tie-rods as well as nuts and bolts generally. Adjust the platinum
contact breaker points in accordance with the data shown under Specifications, and check the
chain tension and lubriCation.
Fig. 6
Transmission
The transmission components consist of a clutch and gearbox. The clutch is of the multiple
plate type, with steel and phenolic resin discs, turning in an oil bath. It is mounted on the
primary shaft of the gear box. The clutch housing, which is made of .spec.ial hardened steel,
tUrns on two internal bearings and is lubricated with the engine sprocket.
The clutch is operated by a hand lever on the left hand side of the handlebar.
The transmission between the engine and the primary shaft of the gear box is through gears
with a reduction ratio of 2.44:1.
The constant mesh, 5-speed gearbox is mounted in the crankcase and is operated by a foot
pedaL.
Bottom gear - 2.236:1
Second gear - '1.562:1
Third gear - 1.203:1
Fourth gear - 1.000:1
Fifth gear - 0.887:1
Transmission between the gearbox and rear wheel is effected by a chain drive with a ratio of
2.250: 1.
Frame
The frame of the Oucati 750 GT is made of high tensile steel in a stylish modern design and is of
the central girder type.
Suspension
The front suspension consists of Oucati double action, long stroke hydraulic forks.
The rear suspension is effected by a strong hinged fork with double action hydraulic shock

4
absorbers which can be adjusted to three different loads.
In the Ducati 750 GT the fork fulcrum spindle is fixed to the frame while the fork rotates
around it through a bronze bush, giving the machine greater solidity and stability. On the left
hand side bush there is a grease nipple for the spindle.
Wheels
The wheels are of the spoke rim type in light alloy, the front being 19" x2" and the rear, 18'; x 3"
at the rim. Both wheels have a detachable spindle. The rear wheel has a special cushion drive
and can be dismounted without removing the chain.
Brakes
The front brake is a disc brake with a telehydraulic control on the handlebar, while the rear brake
is of the drum type, pedal controlled.
The front disc diameter is 280 mm (11.02") and the diameter of the double cam rear drum in
200mm (7.87"). ELECTRICAL SYSTEM
General specifications
The electrical system consists of the following main parts:
Headlamp - A powerful, two filament 12 Volt, 4O/45W headlamp is fitted, together with a 12
Volt, 3W parking light. Inside the headlamp there is a relay for the emergency lights as well as a
circuit for the fitting of direction indicators.
Dashboard - This is mounted on the handlebars and contains the speedometer and
tachometer as well as three warning lights for ignition key, high beam and parking light. The
instruments are lit by two independent lights.
Coils - The two 12 Volt high tension coils are fitted under the tank and become live only when
the ignition key is inserted. When replacing them be sure not to reverse the connections.
Horn - The 12 Volt horn is mounted under the handlebars.
Stop lamp switch - A new type of switch is mounted on the left and rear of the frame and is
operated by the brake pedaL. IMPORTANT:The two wires must be inserted in such a way as to
avoid contact with the central sheath and they must be properly insulated.
Key switch - This is positioned under the saddle on the left hand side, on models fitted with an
electric starter there is an additional starting position.
Fuse box - There are four fuses located under the saddle, inside the tool box. The fuses are F.1
15A to protect the parking light, F.225A to protect the headlight, F.3 15A to protect the horn
and stop light and FA 15A to protect the emergency light and direction indicator circuit.
i M PO RT ANT When replacing a fuse, flex the contact springs so that they hold the fuse firmly in
position.
Battery - The battery is a Yuasa 12N-12A-4A-12V, with 6 cells and Volt - 12Ah capacity. It
has a transparent case to allow easy checking of the electrolyte level and is cushioned by a
special rubber mounting. When checking the battery level with an ammeter always ensure that
the engine is STOPPED.
Regulator - A standard 12 Volt regulator is fitted. Please note that the negative cable from the
battery must be connected to the regulator frame.
Alternator - The alternator has an output of 150 Watts and is mounted within the engine on
the clutch side. The three wires from the alternator connect directly to the regulator and it is
important not to confuse them. When opening the engine take care not to damage the
alternator windings.

5
Plate holder - The rear number plate is lit by a two filament 5/21 Watt bulb.
Handlebar controls - Left hand side: light switch and horn button.
Right hand side: Switch for emergency lights and indicators.
Fittin~ of Direction Indicators
The four lamps must be mounted on the supports already designed on the motorcycle. Using
cable with a 1 mm square cross section connectthe front indicators to the terminals inside the
headlamp and the rear ones from the fuse box terminals under the saddle, ensuring that 12 Volt,
15 Watt bulbs are used.
.The handlebar control is already connected.
IMPORT ANT
The engine cannot be run without a battery as there would be no current to the rectifier. In fact
the engine can only be started if the battery voltage exceeds 8 volts.
The battery cables must not be detached while the engine is running as this would damage
the rectifier.
Advantages of the Electrical System
The electrical system employed in the Ducati 750 GT offers sevèral advantages over previous
systems. The four fused circuits in particular simplify the tracing of electrical failures, while
allowing the unaffected circuits to continue functioning.
Operation of the Electrical System
1. Key inserted:
The engine can be started and the white ignition light in the centre of the dashboard
remains alight until the engine is stopped. The battery is recharged while the engine is
Running.
Light Switch: Centre position - Lights off
Left position - The rear and front parking lights come on as well as the
green warning light on the dashboard.
Right position - The headlight comes on and can be switched to low or
high beam, the red warning light on the dashboard in-
dicates high beam.
In all positions the battery charge remains balanced. When the headlight is switched on the
small parking light is also on, giving the rider a safety light in the event of the main bulb
burning out.
The horn operates.
The stop light operates.
2. Key not inserted:
The engine cannot be started.
Light Switch: All positions remain as above.
The connection between the battery and the electronic current regulator is cut.
The horn does not operate.
The stop light does not operate.
HOW TO CHECK IGNITION ADVANCE
Periodically check the ignition spark advance (after the first 600 and later every 1,200 miles);
ensure that the automatic advance works properly, that it is lubricated and that the springs are
neither out of shape nor out of place.
The rotary movement of the automatic advance must be 140, equal to 280 on the driving
shaft. If you have any doubt get it checked by a specialist workshop. To check the spark
advance, proceed as follows:

6
1. Remove the threaded plug which is at the driving shaft level and fit a suitable timing chart.
(Fig. 7).
2. Fit an indicator on one of the screws that secure the cover.
3. Bring the piston of the vertical cylinder to T.D.C. of the compression stroke and set the
indicator at "0" on the timing chart.
4. Rotate the driving shaft anti clockwise for about a quarter of a turn.
5. Connect a 12V-3W lamp to the spring of the contact breaker in series with the positive pole
of the battery (Fig. 9). The lamp should light up.
Fig. 9
RETARD
+ OF THE BATTERY
1 VERTICAL CYLINDER
2 HOFlizaNTAL CYLINDER
6. Rotate the driving shaft slowly, clockwise, until the light goes out or its intensity is lowered.
At that precise moment the indicator should show an advance of 100.(Fig. 8),
7. Repeat the above test for the sake of accuracy.
8. Repeat the test for the horizontal cylinder, taking care to set the indicator at "0" on the
timing chart. .
9. If the reading does not tally with the required figure, loosen the two screws (A and B) which
secure the plate, and rotate it, advancing or retarding the ignition until the correct reading of
100 is obtained.
10. Bear in mind that, if the felt which lubricates the cam is allowed to dry out, the fibrous
slipping block, which opens the moving part of the contact breaker arm, wil tend to wear,
reducing the size of the gap.

7
Checking the total advance with a stroboscope
Carry out the following:
1. Mountthe advance checking indicator 88713.0109 on
the driving shaft centre line, flywheel side, after removing
the plug 0400.49.090.
2. Connect the stroboscope light cable to the spark plug
in question.
3. Start the engine and run at about 2,500-3,000 r.p.m.
then shine the stroboscope on the reference mark for the
cylinder being tested, placed on the clutch side cover.
4. The phasing indicator must align with the reference
mark, and the ignition coil should be turned clockwise to
advance and anti clockwise to retard until the two
coincide.
SPECIFICATIONS-8GO
Engine
Four stroke twin cylinder, 900 longitudinal "L" configuration, supported in a cradle frame.
Bore: 86mm (3.387")
Stroke: 74.4mm (2.93")
Total Capacity: 86.9cc. (52.700 cu. in.) .
Compression ratio: 9:1 .
The engine is basically similar in construction to the Ducati 750, with the exception of the
electronic ignition system.
Ignition
The electronic ignition system consists of the following components:
a) Generator - with the magnetic flywheel attached to the axle on the left hand side. Access
to the generator is via the left hand cover and clutch.
To time the ignition: 1. Fit the protractor wheel to the engine axle.
. 2. Bring the vertical cylinder to T.D.C. and setthe protractor wheel at "0"
3. Rotate the engine anti-clockwise and position it at 38° in advance.
4. Turn the magnetic flywheel using a pin inserted into the hole, rotating
it until the pin slips into the corresponding hole on the stator plate.
5. Tighten the three screws which fasten the stator plate.
b) Transducers - mounted under the fuel tank.
c) Spark plugs - Champion L 88 type.
Data 860
With a valve/rocker clearance of 0.05-0.08mm (0.002"-0.0031"), inlet and 0.01-0.12mm
(0.0039" -0.0047"), exhaust, the valve timing is as follows: Inlet opens at 48° before T.D.C. and
closes at 830 after B.O.C. Exhaust cpens at 830 before B.O.C. and closes at 480 after B.D.C.
Clearances should be set with the engine cold and after the timing has been adjusted.
Fuel
Petrol is gravity fed to two Dellorto carburettors, type PH F 32 AD for the front cylinder and type
PHF 32 AS for the rear. The main jet is set at 122, and the idle jet at 60. The taper needle equals
K/6 at the second notch and the diffuser measures 32 mm.

8
The inlet filters are FISPA 062459 reference number 0960.91.715 for the front cylinder, and
0960.91.815 for the rear.
Lubrication
The engine is pressure lubricated (see 750 for details of oil capacity and replacement).
Transmission
The transmission system is essentially similar to that of the Ducati 750 with the following gear
ratios utilised:
Primary reduction 2.187:1
Bottom gear 2.237:1
Second gear 1.562: 1
Third gear 1.204: 1
Fourth gear 1:1 (direct drive)
Secondary ratios 2.467: 1
2.533:1
2.5:1
Suspension
T¡he front suspension consists of Ceriani type forks and the rear suspension of Marzocchi,
hydraulic shock absorbers.
Wheels
The wheels are similar to those fitted to the Ducati 750. Recommended tyres are front -3.50
H18Pirell Supersport, inflated to 31.3Ib/sq. in. rear - 120/90-4.70 H18 Pirell Supersport,
inflated to 35.5Ib/sq. in.
Electrical System -860
The system is essentially similar to that installed in the Ducati 750, with the exception of the
electronic ignition circuitry. Five fuses protect the components: F1,25A, General: F2,8A,
Parking Lights: F3,8A, Lights and emergency lights: F4,8A, Stop light and horn: F5, 8A,
Direction indicators. The headlight is a 50/55 Watt, 12 Volt quartz iodine bulb and the
dashboard warning lights are as follows:
GEN - Red - Key inserted
L - White - Lights on
Hi - Blue - Main beam
N - Green - Gears in neutral
Yellow flash - Turn indicator
The horn has two settings, for town and country.
Battery
Kick start models - YUASA type 12N-12A-4A, 12 Volt and 12Ah.
Electric start models - YUASA type B68, 12 Volt and 32Ah.
The battery is recharged by the alternator through an electronic voltage regulator. The
alternator produces 150 Watts at 12 Volts and is installed on the right hand side of the engine.
Emergency Switch
The emergency earthing switch on the right handlebar is required by American law. It operates
by earthing out the two transducers, thus stopping the engine immediately.
Make sure the switch is returned to the RUN position after the engine has stopped.
MAINTENANCE (750 and 860)
The continuing good condition of the motorcycle depends on proper maintenance. By
following the fundamental procedures below you can avoid most serious trouble and continue
to enjoy excellent performance and reliabilty from your motorcycle. The operations to be
carried out are subdivided according to the mileage covered by the motorcycle, and the

9
recommendations which follow are, of course, only indicative, because lubrication, checking
and adjustment depend also on the nature of the road travelled, seasonal temperatures and the
length of the intervening period.
Every 500 Km (300 miles)
- Top up the oil level in the crankcase.
- Check the tyre pressure.
- Tighten the cylinder head bolts.
- Adjust the brakes.
- Check the clearance between valves and rockers, placing the appropriate shim on the valve
stem or adjusting to restore the specified clearances.
Every 1,000 Km (600 miles)
- Check and adjust the distance between the spark plug electrodes to about 0.8 mm (0.0315")
and clean them with a small wire brush and some petrol.
- Clean the contact breaker platinum plates with a rag damped in petrol and check the
distance between them, the gap should be 0.3 to 0.4mm (750 only).
- Check the valve clearances as mentioned above.
Every 1,500 Km (900 miles)
- Check the speedometer drive and lubricate with grease.
Every 2,000 Km (about 1,200 miles)
- Change the crankcase oil, draining it while the engine is hot, and making sure that the oil
drains off completely.
- Remove the carburettor air filters and clean with compressed air.
- Clean out the carburettor float chamber, the main jet and the idle jet.
- Readjust the clutch to take up any wear on the plates.
- Lubricate the hinge of the rear fork.
- Dampen the lubricating wick of the contact breaker cam with thin mineral oiL.
- Uniformly tighten the nipples of the spokes and check that the wheel nuts are secure.
Every 20,000 Km (about 12,400 miles)
- Dismantle the exhaust pipes and cylinders, in order to remove the carbon deposit from the
cylinder heads and pistons. This should preferably be carried out by a Ducati servicing garage.
Headlamp alignment -750
It is advisable to check the alignment of the headlamp periodically as follows:
- Place the motorcycle at a distance of 5 meters (16.404 ft) from a vertical wall.
- Make sure that the ground is even and that the axis of the headlamp is perpendicular to the
walL.
- The motorcycle must be held upright by the rider and not rest on the centre stand.
- Draw a cross on the wall at a height of 0.890 meters (2.920 ft).
- When the high beam is switched on, the cross should be in the centre of the beam.
- To adjust the alignment of the headlamp use the two fixing screws on the front fork or the
three screws on the headlamp ring.
o _ ______
_______ai 0
co N
.. ci ~
, . N
....,.. Ë ~
''', '+ mt. 5.000
ft. 16.404

10
Cleaning
The motorcyle should be washed and cl.eaned periodically, according to the length of time it has
been in use and the nature of the roads covered.
- Clean the engine with paraffin and wipe it dry with a clean rag.
- Wash down the painted parts of the frame with water, using a sponge for washing and a
chamois leather for drying.
- Never use solvents, petrol, spirit or paraffin on the paintwork as they wil dull the finish.
- Grease the chromium plated parts with vaseline and polish with a chamois leather.
Laying the motorcycle up for long periods
If the motorcycle has to be stored for a long period it is advisable to adopt the following
procedure:
- Clean the motorcyde thoroughly.
- Empty the fuel tank.
- Take out the battery and keep it charged.
- Squirt some oil into the cylinders through the spark plug holes and turn the engine several
times by hand, to distribute a thin film of oil on the cylinder walls.
- Lift the machine so that the motor rests on a block of wood and deflate the tyres.
- Cover the machine with a canvass or other waterproof cover.
Running-in Precautions 860
During the first 2,500 (1,500 miles) do not exceed 4,000 r.p.m. After the first 1,000 Km (600
miles) replace the crankcase oil and filter. Subsequent oil changes should be carried out every
5,000 Km (3,000 miles) and the filter replaced every 10,000 Km (6,000 miles).
Periodic Disc Brake Maintenance (750 and 860)
Clean the hydraulic pump and calipers clean but NEVER use petrol or oiL. When necessary use
brake fluid, taking care not to touch paintwork which could be damaged.
Maintain the level of fluid in the reservoir at about 8-1 0 mm below the rim. Always replace the
rubber casing and tighten the cover.
. Check that the hydraulic line is not damaged in any way and that there are no fluid leaks.
When the brake pads are worn to about 1.5 mm of the shoulder plate they should be
renewed. -
Replacement of brake pads
Remove the securing cotter pins and extract the pads. Clean the visible parts of the pistons with
a clean rag moistened with brake fluid, NEVER with petrol or oil, when they are clean, replace
the pistons in the calipers. When remounting the pistons it is advisable to release some fluid
from the caliper drain screw, to avoid fluid spiling from the reservoir. Ensure that the screw is
closed securely after replacing the pistons.
Clean the inner parts of the pad mountings, insert the new pads and fit new cotter pins,
bending the ends with pliers to secure them.
Operate the brake lever several times to allow the new pads to settle into position and, if
necessary, restore the fluid level in the reservoir.
Avoid sudden braking immediately after fitting new pads.

11
CARE OF THE BATTERY
How to prepare the battery for filing
Remove the gummed tape and the plugs before fillng with electrolyte.
If the battery is provided with a long drain pipe, cut the seal about 3 cm from the end. If the
battery has a short sealed tube and comes with a separate long pipe, fit the long pipe.
Filing the battery
The electrolyte (Dilute sulphuric acid) must have a specific gravity of 1.240 in tropical climates
where the average temperature exceeds 25°C (77°F) and 1.260 in mild climates.
Fil to the level of the anti-splash gauze, as indicated on the side of the battery.
The electrolyte should be cooler than 30°C (86°F) before filling.
After the battery has been filed, allow it to stand for half an hour; during this period some of
the electrolyte wil probably be absorbed and if so, the level must be restored by adding more
dilute sulphuric acid as above.
Charging the Battery
It is preferable to charge the battery fully before installng it in the motorcycle, applying a
current of 1.2A for between 15 and 20 hours. Charge until the battery electrolyte reaches the
density referred to above. .
Mounting
- Secure the battery firmly in position on the motorcycle.
- Make sure that the terminals are correctly connected, damage to electrical parts can result
from current of the wrong polarity being applied.
Maintenance
- Check the electrolyte level once a month and top up with DISTILLED WATER. Never top up
with sulphuric acid.
- Always keep the battery clean and ensure that the drain tube is unobstructed.
- Recharge the battery when the horn and lights indicate that the current is low.
Maintenance of the Electrical System .
It is extremely important to refer to the wiring diagram on page 63 when carrying out inspection
or repairs to the electrical system. To avoid demagnetizing the alternator take care never to
reverse the polarity of current passing through it. Always use the appropriate meters when
testing.
If the electronic regulator fails to function, do not tamper with it, send it to a Ducati agent for
servicing, or replacement.
NEVER detach the battery cables when the engine is running or damage to the electronic
regulator wil resûlt,
Refer to page 57 for further information.

12
LOCATING AND REMEDYING FAULTS
The following list contains several of the most frequent faults which may arise and advice on
remedying them.
ENGINE DOES NOT START EASILY
First of all, ascertain that there is enough petrol and that the cock is turned on. (A = open; R =
reserve). If this is in order, the fault may be one or more of the following:
CAUSE REMEDY
Petrol pipe is clogged. Blow through it until the obstacle is
removed.
Petrol filter dirty. Dismantle the filter and clean the gauze
by air blast.
Petrol cock filter is dirty. Dismantle the filter and clean it by a
blast of air through the gauze.
Carburettor float stuck. Remove the float and clean out the
float chamber.
Carburettor float leaking. Change the float.
Jet is clogged. Remove the obstacle by a strong blast
of air.
The cable of the ignition coil is broken or Inspect the cable insulation for faults
sparking externally. and if necessary change the cable.
Defective sparking plug. Change or clean the plug, making sure
that the insulating core is not damaged,
that there are no carbon deposits on the
electrodes and that the spark gap does
not exceed 0.8mm (0.0315").
The contact breaker points do qot open. Check the position to the fixed contact
point.
The contact breaker arm is seized on its Check movement between rocker arm
pivot. and pivot if necessary.
The contact breaker points are dirty. Clean the contact breaker points with a
rag damped in petrol
The capacitor has broken down or is short Change the capacitor
circuited.

CAUSE
Compression low.
A valve spring is broken.
Valve sticking.
The rocker adjuster is worn out.
The battery is discharged.
The battery quickly discharges because of
a fault or break in the recharging circuit.
With key not inserted battery discharges.
13
REMEDY
Check if the sparking plug has been
tightly screwed in, check the valves for
gas-tightness and the tightness of the
piston rings.
Change the broken spring.
Dismantle the valve, clean the valve
stem and the bore of the valve guide,
and make sure that the clearance
between stem and bore does not exceed
0.8mm (0.0032").
Recheck the clearance by fitting the
rocker shim on the valve stem end.
Recharge the battery according to the
instructions on page 11.
Disconnect the wire from the + ter-
minal block ofthe battery.
- Insert an ammeter in between the
terminal clamp and the wire.
- Insert the ignition key and let the
engine turn, til attaining 6,000 r.p.m.
The ammeter should show:
a) maximum current about 10A, with
completely discharged battery.
b) minimum current about 1A, with
completely charged battery.
According to the battery load condition,
you wil obtain intermediate figures.
These tests must be carried out with
switched off headlight.
Checking the Electrical System.
Make sure that all the bulbs are
efficient.
1) With the lights switched off, the
ammeter should read 0 at 1,100 r.p.m.
approx.
2) With town lights switched on (during
the night) the ammeter should read
Oat 1,400 r.p.m. approx.
3) With the antidazzle lights switched
on the ammeter should read 0 at 2,300
r.p.m. approx.
Check if there are earthed contacts in
the system.

CAUSE
Irregular feed of petrol to the carburettor.
Main jet partly clogged.
Carburettor butterfly valve does not open
completely.
The float needle does not close properly.
Petrol of bad quality.
The spark plug is not of the right type.
The plug is loose.
The sparking plug cable sparks externally.
The spark gap between the electrodes of
the sparking plug is too wide.
The sparking plug electrodes are dirty.
The contact breaker opening is excessive.
(750)
The secondary winding of the coil is
short-circuited or broken (750) -
The silencer is almost completely
clogged-up.
14
REMEDY
Clean the carburettor filter, the petrol
cock filter and the petrol pipe.
Clean the main jet by means of an air
blast.
Readjust the valve travel by means of
the adjustment screw of the carburettor
Bowden cable.
Clean out the carburettor and especially
the needle seat.
Empty the petrol tank and refil at a
reliable garage.
If the sparking plug overheats, you will
have preignition, knocking, and missing,
especially at high revs. If the sparking
plug remains too cold, you wil have no
ignition, because the electrodes wil
short-circuit. Use the right type of
sparking plug; we advise the use of a
plug having a thermal figure of 260 of
the Bosch international scale.
Tighten the plug down welL. A washer
should always be placed between the
sparking plug and its seating in the
cylinder head.
Change the cable or repair the insulation
Adjust the gap to the proper width of
aboutO.8mm (0.0315").
Clean the electrodes with a wire brush.
Readjust the exact opening of the
contact which is 0.3-0.4 mm ~ 0.0118"
to 0.0157".
Change the coil (at a Oucati Servicing
Garage).
Clean the silencer, to ensure free dis-
charge of the spent gases.