digiplex question

[alanjw]

hi all ....just a quick question ...currently have a digiplex 2S med 442A fitted to my 906 ,managed to aquire ,secondhand, a digiplex 2S med 446A . they both work (in the garage not had chance to get out on road yet ) is there a difference ?
thanks for any info chaps

[ducinthebay]

I can't answer that question, but I have a question of my own.
The vauum hose that runs from the intake manifolds to the computer, is that for some amount of vacuum advance of the timing? If I pull vacuum on it, should the timing advance? (speed up?) I grabbed mine the other day, and put a hand held vacuum pump on it and nothing happened. Am I testing it wrong?

I have a second computer that I will be testing soon, but they only way I can figure out to test it is to install it.

Cheers,

[ducinthebay]

For a bike of such small production numbers, there seems to be a lot variation here.

I have 5 of these Digiplex 2s boxes. (from different sources)
2- 441A - Red label with yellow and black printing
2- 442A - Blue label with red and yellow printing
1- 902A - White label black label

Everything else about the boxes looks the same.

A project for a lazy afternoon is to take all of these boxes, plug them into the bike, and take them for a ride to see which ones work, or work better.

So, what's in your bike?

Cheers,

[higgy]

both of the ones I have are 442a one from bike number 16 the other 281

[paso750]

http://www.crengineering.de/steuergeraete/

G.

[higgy]

Another fine keeper from the "G" man

[ducinthebay]

Outstanding chart, however, I dont find the 441A on it at all. I got two of those. Wonder what they will do?
Now that I know the 902 is from a Moto Guzzi, it will be interesting to see what it does in the Ducati.
Is there any information as to how the vacuum advance works, if it does at all?
Anybody ever run with out it?

Cheers,

[higgy]

441a was for a guzzi nevada

[paso750]

the Digiplex regulates fuel mixure and ignition timing/curve, does it ?
Is it then not risky to just try a different one ?

G.

[Tamburinifan]

Since 906 is carbed, Digiplex only controls ignition.

[paso750]

right, didn`t think about that

[ducinthebay]

Since the Guzzi is also a 90 degree V-twin, the timing may (or may not) be correct. Stay tuned to see what works from my pile.

So, with a single pickup on the engine, the timing and the advance curves are all set by the Digiplex. Are there any advance curve data around for the different models? I'm sure that Magnet Marelli has it, but is it on the web anywhere? I mostly want to confirm that the box I have is working correctly. Still befuddled about that vacuum line.

- Can you change / alter the timing in any way?
- Is there an electronic limiter built in?
- As best I can tell, the only inputs to the box are 12v, a vacuum line, and a signal from the crank position sensor. Correct? Outputs are the pulses to the coils.

Cheers,

[Tamburinifan]

Standard Kokusan boxes gives 6 degrees up to 1700 RPM, and full advance 32 degrees from 2700 RPM.
That`s it, same on 750 Paso and all 90`s carbed 600-900`s.
I don`t know if 906 is different in anyway what they need ignitionwise.