Myrons Mopeds

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Magneto Types

type 1: Internal ignition ground
type 1: Internal spark coil
wire colors: ignition, lights
For off road and countries that do not require a brake light.

type 2: Internal ignition ground
type 2: External spark coil
wire colors: ignition, lights
For off road and countries that do not require a brake light.

type 3: Internal ignition ground
type 3: Internal spark coil
type 3: Brake light
wire colors: ignition, lights, brake light
For countries that require a brake light.

type 4: Internal ignition ground
type 4: External spark coil
type 4: Brake light
wire colors: ignition, lights, brake light
For USA and countries that require a brake light. This type has a 1-wire ignition source coil and a 2-wire lighting coil. The lights coil has a center tap that powers the brake light. This makes the lights coil have less windings, making the headlight dimmer. But the engine never looses spark because of the lights.

type 5: External ignition ground
type 5: External spark coil
type 5: Brake light
wire colors: ignition, lights, brake light
For USA and countries that require a brake light that does not dim the head light. This type has a 2-wire ignition source coil and a 1-wire lighting coil. The green external ground wire powers the brake light. This allows room for a more powerful lights coil, to give a brighter head light. But the engine can loose spark if the brake light wires become loose.

 

 

 

 

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Source Coil Substitution

Here are the bolt hole (4mm) spacings for various moped source coils.

mm plate x wheel  maker

46     Ø94 x Ø79 Motoplat 0602007 ’83-86 Derbi
46     Ø94 x Ø79 Motoplat 0602062 ’86-89 Derbi
47     Ø80 x Ø82 Dansi
47     Ø94 x Ø82 Dansi
47     Ø80 x Ø79 Motoplat late Sachs 504
47     Ø94 x Ø79 Motoplat 9600099 ’76-82 Derbi
47     Ø80 x Ø80 Bosch
47     Ø94 x Ø90 Dansi
48     Ø80 x Ø80 CEV
48     Ø94 x Ø80 CEV
48     Ø89 x Ø89 Motobecane
50     Ø90 x Ø89 WTEMCO? Indian
54     Ø90 x Ø90 Bosch
55     Ø94 x Ø79 Motoplat late Sachs 505
55     Ø95 x Ø95 Peugeot
57     Ø90 x Ø94 CEV mid-80’s Tomos
57     Ø90 x Ø94 Ducati early Tomos

From this list, besides ∅82 Dansi there are two source coils (in Myrons Mopeds inventory) with 47mm hole spacing: ∅80 Bosch, and ∅79 Motoplat. A Batavus or Trac M56 source coil would “drop right in” and fit perfectly. But the edge is farther from the flywheel magnet. So the spark would not be as strong. It would be OK going fast, but when idling it might loose spark. The spark plug gap could be reduced to compensate.

In the photo, the distance is measured, from edge of the 4.0mm hole to the edge of the steel plates. Dansi is 5.3mm, and Bosch is 3.9mm. You can see the difference is 5.3 – 3.9 = 1.4  The Bosch substitute is 1.4mm farther away from the moving magnets.