Aprilia Ditech 50 AC 2002 Owner's manual

aprilia

QUICK WORKSHOP

HANDBOOK

Electronic air injection
Aprilia Ditech Engine

1095 2

General safety
norms

Technical data

Oil chart

Special engine tools

Injection troubleshooting

Disassembly/Reassembly
sequence

1

2

3

44

5

6

Air-injection 50 cc

INTRODUCTIONCONTENTS

- This manual contains all the essential information for
carrying out routine vehicle procedures.

- The information and diagrams in the manual are up­to-date at the time of publication.

- This publication is intended for use by Aprilia dealers
and their trained mechanics. A large number of
procedures do not require explanation and therefore
have been omitted. It has not been possible to give
detailed mechanical data for every procedure. All per­sonnel consulting this manual must therefore possess
the basis skills of a mechanic and be thoroughly familiar
with the most common motor cycle repair procedures.
Without these skills and the necessary familiarity any
repair or routine maintenance operation may be
ineffective or even dangerous.
Given the fact that it is not possible to provide detailed
descriptions of all procedures, special care must be
taken for whatever repair or maintenance work is done,
in order to prevent damage to the vehicle and injury to
persons.
In order to provide the best level of customer
satisfaction, Aprilia s.p.a. constantly improves its
products and relevant documentation. All important
technical changes and alterations to procedures are
notified to all Aprilia dealers, branches and points of
sale throughout the world. All changes will be included
in later editions of this manual.
If you have any doubts or queries about the procedures
described in this manual, please contact the Aprilia

Training and Documentation Department, who will be

pleased to give you all the information and explanations
you require, and to bring you up-to-date with any
changes.
For further information see:

- SPARE PARTS CATALOGUE no. 5601

Produced by
Training and Documentation Department

aprilia s.p.a.

Via G. Galilei, 15 - 30033 Noale (VE) - Italy
Tel. +39 - 041 55829111
Fax + 39 - 041 441054
www.aprilia.com

Produced and printed by

Studio Gallo Design srl

Via Mogno,34/1
35012 Camposampiero (PD)
tel. 049 - 9303475
fax. 049 - 9317954
Italy
www.stgallo.it
e-mail: [e-mail]

Release 00 / 2002 - 09

Without alteration to the basic features of its models
as described and illustrated in this manual, Aprilia
s.p.a. may carry out modifications to any of the models
without notice.
Unauthorized electronic retrieval or reproduction of any
part of this manual is unlawful in all countries. Products
or services manufactured or provided by third parties
are quoted merely as examples and do not constitute
a recommendation; Aprilia s.p.a. is not liable for the
performance or use of such products and services.

First edition. September 2002.

01 / 01Chapter.1

Air-injection 50 cc

GENERAL SAFETY NORMS

CARBON MONOXIDE

If the engine must be switched on to carry out certain
operations make sure the room is well ventilated or
open to the outside. Never switch on the engine in a
closed room, unless there is a smoke and fume removal
system installed

and the operating.

DANGER

Exhaust fumes contain carbon monoxide, a
poisonous gas which make cause loss of
consciousness and can be lethal.

Switch on the engine only in an open space or in a
closed room if fitted with a fully operating smoke and
fume removal system.

FUEL

Make sure the room is well ventilated. Extinguish all
cigarettes, keep fuel containers away from flames and

possible sources of sparks.

DANGER

Fuel is highly flammable and may explode.
Take special care to check the air and fuel injection
plant hoses; the operating pressure should not
exceed about 750 KPa (7.5 bar).
Any fuel hoses which are cut or cracked should be
replaced.
KEEP OUT OF THE REACH OF CHILDREN

HIGH TEMPERATURE COMPONENTS

DANGER

The engine and parts of the exhaust system reach
very high temperatures and remain hot for a certain
period after switching off the engine. Handle these
components only after putting on protective gloves
or waiting for the engine and parts to fully cool
down.

WASTE TRANSMISSION OIL

DANGER

Use latex gloves for maintenance operations
involving contact with oil. If left in contact with the
skin for long periods, used engine oil can cause
skin cancer. Although this is unlikely, unless
handled every day, wash your hands with soap and
water after handling used engine oil.
KEEP OUT OF THE REACH OF CHILDREN

GENERAL PRECAUTIONS AND INFORMATION

For repair and disassembly and reassembly operations
follow the instructions.

DANGER

Do not carry out any operation in the presence of
naked flames.
Before starting any maintenance or inspection
operation, switch off the engine and remove the
ignition key. Wait for the engine and exhaust
system to cool down. Place the motor cycle, if
possible, in a raised position on a level, even
surface. Take special care of heated parts (engine
and the exhaust) in order to avoid burns.
The vehicle is made with parts which cannot be
swallowed. Do not bite, chew, suck or otherwise
attempt to carry out operations using the teeth or
mouth.
Unless otherwise specified, to reassemble parts,
reverse the order for disassembly operations.
Some operations may involve disassembling parts
previously disassembled for other operations to
be carried out. Consult the various pages of the
manual where each operation is described in order
to avoid unnecessary work. Never use fuel as a
solvent for cleaning the vehicle.
If welding operations are to be carried out,
disconnect the negative pole (-) of the battery and
take special care with all electrical components
used for the injection system.
If more than one person is working on the vehicle
make sure both are in a safe position whatever the
work being done.

Release 00 / 2002 - 09

Chapter.1

01 / 02

Air-injection 50 cc

BEFORE DISASSEMBLY

- Remove dirt, mud, dust and foreign bodies from the
vehicle before disassembling the components.

- Use all the tools specifically designed for the vehicle.

DISASSEMBLY

- Before separating pipes or wires etc. (joints and
junctions) mark each part with a unique marking.
Each piece should be clearly marked for reassembly

purposes.

-Clean and wash the disassembled components with
close to non-inflammable detergent.

-Keep paired parts together, because normal wear and
tear create a natural pairing. In some cases, where
one part is replaced the other must also be replaced.

Keep away from sources of heat.

REASSEMBLY

DANGER

Never re-use a snap ring. If removed, replace it with
a new ring. If a new ring is fitted, do not stretch
more than necessary when fitting it to the shaft.
Afterwards, check that the ring is properly fitted to
the housing.

- Lightly smear the edges of oil seals with lithium based
grease.

- Refit the oil seals and bearings with the trademark or
manufacturer’s serial number facing outwards (so it
is visible).

- Grease the bearings fully before fitting.

- Check that all components have been reassembled
properly.
After a maintenance or repair operation, carry out
preliminary checks and commission the vehicle on
private property or in a low traffic area.

Do not clean bearings with compressed air.

IMPORTANT Bearings must rotate freely, without

sticking or noise. Replace if necessary.

- Use only ORIGINAL Aprilia SPARE PARTS.

- Stick to the oil chart and recommended wearing parts.

- Wherever possible, lubricate parts before
reassembling them.

- When tightening screws and nuts begin with the
largest diameters, or inner nuts and screws, and
tighten diagonally. Tighten each before finally
tightening to the specified torque.

- Always replace gaskets, gasket rings, snap rings, O­rings and split pins with new ones.

- Clean all joint surfaces, oil seal edges and gaskets
before reassembling.

Release 00 / 2002 - 09

01 / 03Chapter.1

ENGINE

Air-injection 50 cc

TECHNICAL DATA

Type
Engine type
Number of valves
Number of cylinders
Piston displacement
Bore/Stroke
Corrected compression ratio
Idle rpm
Starter system
Clutch
Gearbox
Lubrication system
Cooling system

TRANSMISSION

Variator
Primary
Gears

Secondary

CAPACITY

air/injection

air-injection with direct petrol injection

-

mono-cylindrical horizontal

49.38 cm

41.0 mm / 37.4 mm
rc = 10.7 ± 0.1

1650 ± 50 r/min

electric

centrifuge

automatic stepless variator

Electric oil pump

forced air

automatic stepless

V- belt

minimum for stepless change: 2.9

maximum for stepless change: 0.75

with gears

3

Transmission oil

THROTTLE BODY

Type
Diffuser

FUEL SUPPLY

Fuel injector
Air injector

IGNITION UNIT

Type of ignition
Ign advance

SPARK PLUG

Standard
Electrode-spark plug distance

ELECTRICAL INSTALLATION

Battery
Fuse
Generator (magneto)

130 cm

Ø18 mm

SIEMENS DEKA

SYNERJECT

Inductive

Variable: 20° at 3000 rpm 17° at 7500 rpm.

NGK R CPR8-E

0.55 - 0.65 mm

12 V - 4 Ah

12 V - 140 W

3

BING

7.5 A

Release 00 / 2002 - 09

02 / 01Chapter.2

Air-injection 50 cc

TIGHTENING TORQUE 50 cc AIR INJECTION ENGINE

Application

Pick-up locking
Stator locking
Transmission steel plate locking
Throttle body (with roller) hose clamp locking
Suction manifold (built-in, hexagonal) locking

Screws and pin securing intake manifold

Transmission cover
Variator cover
Bendix support locking
Starter motor
L/r carter locking

Wheel bearing retaining plate locking
Oil load plug (flanged)
Oil unload (Ch. 8)
Variator sliding pulley cover locking
Head locking (nut)
Clutch locking (nut)
Flywheel locking (nut)
Exhaust stud
Cylinder stud

Spark plug (thread)

Compressor screw locking
Fuel rail screw locking (flanged TE)
Variator fixed pulley locking (nut)

Cylinder head temperature probe

Screw

M5 x 12
M5 x 25
M6 x 12

M6 x 20

M6 x 25
M6 x 25
M6 x 30
M6 x 25
M6 x 55
M6 x 75

M6 x 100

M6 x 16
M8 x 12
M6 x 12

M4 x 8

M6 h=9

M10x1.5

M10x1.25

M10x1.0

M5 x 20
M5 x 25

M12x1.25

6 - 9

TIGHTENING

TORQUE

Nm

4 - 6
4 - 6

8 - 12

end stop

8 - 12
9 - 11
8 - 12
8 - 12
8 - 12
8 - 12
8 - 12

6 - 10

10 - 14

5 - 6

2

11 - 13
45 - 55
35 - 45

4 - 5
4 - 5

13 - 15

4 - 5
6 - 7

35 - 45

6 - 9

Kgm

0.4 - 0.6

0.4 - 0.6

0.8 - 1.2

end stop

0.8 - 1.2

0.9 - 1.1

0.8 - 1.2

0.8 - 1.2

0.8 - 1.2

0.8 - 1.2

0.8 - 1.2

0.6 - 1.0

1.0 - 1.4

0.5 - 0.6

0.2

1.1 - 1.3

4.5 - 5.5

3.5 - 4.5

0.4 - 0.5

0.4 - 0.5

1.3 - 1.5

0.4 - 0.5

0.6 - 0.7

3.5 - 4.5

0.6 - 0.9

Sealant

not
not

Loctite 270

not
not
not
not
not
not
not
not

Loctite 243

not
not
not
not
not
not

Loctite 270

not

/
not
not
not

Release 00 / 2002 - 09

02/ 02Chapter.2

TECHNICAL DATA

CYLINDER + PISTON + RINGS

Air-injection 50 cc

Item:

Piston to cylinder
clearance

Piston diam.

Cylinder bore

Air-

injection

Air-

injection

Air-

injection

Standard: mm (in)

0.028-0.040

(0.0011-0.0016)

Selection A 40.966-40.972

(*) (1.6128-1.6131)

Selection B 40.972-40.978

(*) (1.6131-1.6133)

Selection C 40.978-40.984

(*) (1.6133-1.6135)

Measure 18 mm (0.7) from
the outer edge

Selection A 41.000-41.006

(1.6141-1.6144)

Selection B 41.006-41.012

(1.6144-1.6146)

Selection C 41.012-41.018

(1.6146-1.6149)

Limit: mm

(in)

0.100

(0.0039)

40.912

(1.6107)

40.918

(1.6109)

40.924

(1.6112)

41.050

(1.6161)

41.056

(1.6164)

41.066

(1.6168)

Measure 15 mm (0.59) from
the outer edge

Cylinder distortion

Cylinder head distortion

0.005

(0.0002)

0.02

(0.0008)

0.03

(0.0012)

0.05

(0.0020)

(*) N.B. During disassembly selections A,B, C may not be visible. In this case, refer to limit
values.

Release 00 / 2002 - 09

02 / 03Chapter.2

CYLINDER + PISTON + RINGS

Air-injection 50 cc

Item:

Port at the end of the unassembled
segment

Port at the end of the segment fitted
into the cylinder

Segment/slot clearance

Piston pin housing bore on piston

Air-

injection

Air-

injection

Air-

injection

Air-

injection

1°-2°

1°-2°

1°-2°

Standard:

mm (in)

T Approx.

T

12.002 - 12.010

(0.4725 - 0.4728)

0.25 - 0.40

(0.0098 - 0.0157)

0.036 - 0.076

(0.0014 - 0.0030)

4.5

(0.18)

Limit:

mm (in)

3.6

(0.14)

0.70

(0.027)

-

-

12.030

(0.4736)

Piston pin outer diameter

Air-

injection

11.996 - 12.000

(0.4723 - 0.4724)

11.980

(0.4717)

Release 00 / 2002 - 09

02 / 04Chapter.2

CONROD + CRANKSHAFT

Air-injection 50 cc

Item:

Connecting rod small end diameter

Width from crank arm to arm (A)

Misalignment limit (C)

Side clearance of connecting rod big
end (D)

Standard:

mm (in)

Air-

injection

Air-

injection

Measured between two opposite points

Air-

injection

(0.6300 - 0.6304) 36.0 ± 0.05

16.003 - 16.011

37.95 - 38.10
(1.494 - 1.5)

0.15 - 0.75

(0.0059 - 0.029)

Limite:

mm (in)

16.040

(0.6315)

-

-

0.03

(0.001)

-

Standard crank width

Release 00 / 2002 - 09

02 / 05Chapter.2

CLUTCH

Air-injection 50 cc

Item:

Clutch wheel inner diameter

Clutch shoe thickness

Clutch engagement

Clutch lock-up

OIL PUMP

Item:

Inner coil

TRANSMISSION

Standard: mm (in)

110.00 - 110.15
(4.331 - 4.337)

3.0

(0.12)

3200 ± 200 rpm

6700 ± 300 rpm

Specification:

Ri = 26.3 ± 2.6 Ω a 20° C

Limit:mm (in)

110.50

(4.350)

2.0

(0.08)

-

-

Item:

Reduction ratio

Final reduction ratio

Drive belt width

Driven face spring free

Guide roller for variator

Drum diameter

Air-

injection

Air-

injection

Standard: mm (in)

Variable 2.9 - 0.75

51/15 x 67 x 14

18.4 (0.724)

110 (4.33)

17 (0.669)

107 - 107.2

(4.213 - 4.220)

Limit: mm (in)

-

-

17.4 (0.685)

104.5 (4.114)

16.5 (0.650)

107.5

(4.232)

Release 00 / 2002 - 09

02 / 06Chapter.2