Ducati and ZEM Magnetos

Contents:

 1. Ducati magnetos on Tomos

 2. Ducati magnetos on Minarelli

 3. Ducati magnetos on other makes

 


1. Ducati Magnetos on Tomos

Tomos mopeds have been equipped with Ducati, ZEM, CEV, Iskra, AET and other magnetos. They are all included in IDM-Iskra-AET Magnetos. ZEM is a remake or a rename of Ducati (DEM Ducati Elettrotecnica Microfarad).

Ducati or ZEM 31.17.11 magneto-generator is a 2-wire internal ignition ground type for countries that do not require a brake light.

Ducati or ZEM 31.17.30 magneto-generator is a 3-wire external ignition ground type for countries like the US that require a brake light. Like many other US-model moped magnetos, the brake light is powered by the ignition source coil ground. This was to meet the US DOT requirement that the headlight not get dim when the brake light was on. The two-coil generator has three outputs, the black ignition wire from the points to the spark coil, the blue ignition ground wire that is grounded through the brake light or brake light switches, and the yellow light wire the provides 6V AC 30 watts for light and horn.

Tomos US models in 1974 to 1985 had this type of magneto, with the brake light switches wired in series and normally closed when installed. If you removed the tail light and squeeze either brake, the engine would die. Starting in 1986 Tomos improved the electrical system with a solid-state-regulated single lighting yellow wire, a ignition black wire, and an internal ignition ground. So the engine never dies, on a 1986 and later Tomos with the 2-wire Iskra magneto, when the tail light wires are unplugged and the brake is applied. When the magneto type changed from 1985 to 86, the wiring also changed.

These Ducati and ZEM complete magnetos, with 94mm ID flywheel and 90mm 3-bolt stator, will interchange with 90mm ID flywheel and 90mm 3-bolt stator Bosch complete magnetos and other Bosch compatibles like Iskra, except for the width and position of the key groove that determines the ignition timing.

These are counterclockwise ⇐left rotation. Points are M14 CEV type “right hand” (the brown part looks like your right hand sideways with fingers bent). The Ducati base plate has a 17.9mm condenser hole instead of 18.0. So the condenser is MMI# M17T which is the same as a modern M17.  Source coils have M4 x 20 screws with 57 mm spacing.

Ducati# 0 rot id od  od wires V w  Tomos engines
magneto# flywheel# stator assy#
base plate# points# condenser#



31.17.11
⇐94 116  90   ♦ 6V 30/10 Tomos A3-EU ’74-85?
000.000 0 000.000 0 000.000 0 213.738 0 221.309 0 221.310


 
31.17.30
⇐94 116  90 6V 30/10 Tomos A3-US ’74-85 Ducati
213.322 0 213.737 0 000.000 0 213.738 0 221.309 0 221.310



31.17.30
⇐94 116  90 6V 30/10 Tomos A3-US ’83-85 ZEM
213.322 0 213.737 0 000.000 0 213.738 0 221.309 0 221.310

Tomos#  price  Parts for Sale 
700.334 $19.0 flywheel puller M26-1.5 thread
All parts are listed in Tomos A3 Engine Parts section 7c.

 


2. Ducati Magnetos on Minarelli

Ducati magnetos were on many 1950’s to 1980’s Minarelli engines, along with CEV and Bosch. 

Oldest ones had an internal spark coil, where the spark plug wire comes out of the engine. Newest ones had an external spark coil with a spark plug wire coming out of it. In between oldest and newest was both types.

Wires: In the list below the wires column has symbols. is a black magneto wire for lights, is a red magneto wire for ignition, o is a thick magneto wire for an internal spark coil, blank is no thick magneto wire for an external spark coil.

Some bike models with brake lights or batteries have a third magneto wire purple. The third wire can be from the ignition source coil (external ignition ground), or from the lighting coil as an additional output (internal ignition ground). 


This is a Ducati 31.12.38 magneto from a 1974 Indian ME76, Minarelli P6-70 engine, USA street model with a brake light. It has 3 output wires. Red wire is ignition (points to spark coil). Black wire is power for lights. Purple wire is power for the brake light (or battery charging if there is a battery).

 

Ducati# 0 rot id od  od wires V w  Minarelli engines
magneto#  ignition source coil type, spark coil type

flywheel#  stator assy# base plate# points# condenser#
ign. coil#   lights coil#     



31.03.61 ⇒80 103  80 o♦ 6V 18 Minarelli V1
82.0001.9  internal ignition ground, internal spark coil 
82.0201.6  82.0025.6  82.0445.6  82.0011.6  82.0134.6
07.0304.6  07.0404.6



31.03.73 ⇒80 103  80   ♦ 6V 18 Minarelli V1 G1R
82.0029.9  internal ignition ground, external spark coil
82.0229.6  82.0029.6
  82.0445.6  82.0011.6  82.0134.6
07.0108.6  07.0404.6   



31.02.30 ⇐80 110  94   ♦ 6V 18 Minarelli P3 P4S P4V W3
82.0012.9 =912301? =M16-12?  int ign gnd, ext spark coil
82.0212.6  82.0018.6  82.0440.6  82.0006.6  82.0132.6
07.0102.6  07.0411.6


31.02.32 ⇐80 110  94 o   0V 00 Minarelli P4 kit
=M42-208  internal ignition ground
82.0000.6  82.0000.6  82.0440.6  82.0006.6  82.0132.6


31.02.37 ⇐80 110  94 o♦ 6V 18 Minarelli P4 kit
=M42-208  internal ignition ground
82.0000.6  82.0000.6  82.0440.6  82.0006.6  82.0132.6



31.02.39 ⇐80 110  94   ♦ 6V 18 P4 P4V P4E P6 P6/4 P6R W3
82.0014.9 =912401    internal ign. ground, ext. spark coil
82.0214.6  82.0018.6  82.0440.6  82.0006.6  82.0132.6
07.0102.6  07.0411.6


31.02.74 ⇐80 110  94   ♦ 6V 18 Minarelli P6 potenza?
82.0015.9   internal ignition ground, external spark coil
82.0215.6  82.0019.6  82.0440.6  82.0006.6  82.0132.6
07.0102.6  07.0412.6


 
31.12.38 ⇐80 110  94 ♦ 6V 25/10 Minarelli P4S-US P6CS-US
82.0000.9  internal ignition ground, external spark coil

82.0000.6  82.0000.6  82.0440.6  82.0006.6  82.0132.6


31.02.77 ⇐80 110  94   ♦ 6V 18? Minarelli P4? P6?
82.0031.9  internal ignition ground, external spark coil
82.0231.6  82.0036.6  82.0440.6  82.0006.6  82.0132.6
07.0116.6  07.0441.6?


31.12.54 ⇐80 110  94   ♦ 6V 00 Minarelli P3? W3?
82.0046.9  internal ignition ground, external spark coil
82.0246.6  82.0050.6  82.0440.6  82.0006.6  82.0132.6


31.12.37 ⇐80 110  94   ♦ 6V 00 Minarelli P4? P6?
82.0045.9  internal ignition ground, external spark coil
82.0245.6  82.0047.6  82.0440.6  82.0006.6  82.0132.6
07.0127.6  07.0441.6



31.12.50 ⇐80 110  94   ♦ 6V 30/10? Minarelli 125#2 ’74 Indian ME125


31.12.59 ⇐80 110  94   ♦ 6V 00 Minarelli P3? W3? P4? P6?
82.0052.9  internal ignition ground, external spark coil
82.0252.6  82.0046.6  82.0440.6  82.0006.6  82.0132.6
07.0126.6  07.0441.6


31.11.37 ⇐80 110  94   ♦ 6V 00 P4-P6 ’81 Fantic Cabalero
82.0058.9  internal ignition ground, external spark coil


 

 

 

Minarelli#  price  Parts for Sale.
05.0080.0 $19.0 flywheel puller M19-1.0 thread
49.0815.6  none  points screw M4x6 small head slot use M4x8
49.0815.6 $2.50 points screw M4x8 small head phillips
49.0816.6 $0.70 coil screw M4x20 slot

82.0006.6 $16.0 points M14 for left rotation
82.0011.6 $16.0 points M18 for right rotation
82.0132.6 $13.0 condenser ∅17.9 M17T = modern M17
82.0134.6   none  condenser ∅17.9? no mount flange
82.0181.6   none  greasing felt
82.0440.6   none  base plate bare ∅94
82.0445.6   none  base plate bare ∅80

 

 


3. Ducati Magnetos on other makes

Ducati# 0 rot id od  od wires V w  Other engines
magneto#  ignition source coil type, spark coil type


31.03.38 ⇐80 110  94   ♦ 6V 18? unknown app.


 
31.03.47 ⇐80 110  94   ♦ 6V 18? Morini UC4 50
29-0000  internal ignition ground, external spark coil