Electrical Puzzle

Post by **jcslocum** » Mon May 09, 2005 6:59 pm

Hey Carl,

You should be able to test most of it with a simple multi-meter. If it is the same as the 906 set up, you should dig up a service manual and see what it says.

First, I would make sure all connections are very clean. Unfortunately that means taking all of them apart and looking/cleaning every one. Don't forget the ground straps that go to the engine and the battery terminals.

If you find it online, let us know so we can read it thru too.

Jose · Post by **Jose** » Mon May 09, 2005 8:00 pm

Hola ha todos¡¡¡¡

Buscando en los libros y archivos que dispongo he encontrado los esquemas eléctricos del modelo 906 Paso y unos de los últimos modelo de ducati del año 90, estos modelos utilizan el sistema DIGIPLEX.. En cuanto pueda lo escaneo y el que lo quiera se lo mando con mucho gusto por correo electrónico..

Estos esquemas son muy prácticos para poder solucionar muchos problemas.

Tengo unos datos del manual de la 906 que pueden ser útiles para llevar una referencia a la hora de diagnosticar el problema.

En el manual dice:
- para el capturador (PICK-UP)PASO 906 tiene una impedancia de 700 ohmios.+/- 5%
- para las bobinas el primario 3.4 ohmios +/- 10%
- para la bobina secundaria 3700 ohmios +/- 10%

Todo esto ha temperatura ambiente de 20º C .Estos datos son orientativos.

En este manual habla un poco del sistema eléctrico y su procedimiento para resolver algunos problemas.

JOSE...

Post by **Skins** » Mon May 09, 2005 8:41 pm

TRANSLATION

Jose says he found wiring diagrams for the 906 and for the last Ducatis of the year '90, which use the DIGIPLEX system, and he can email them to those who need them.

He says these plans should be very useful for many problems.

He says he has some data for referrence purposes

He lists the test ohms for

- the PICK UPS (see above)
- the coils primary circuit (see above)
- and the coils secondary circuit. (see above)

These readings are at 20 deg C and polarity-sensitive.

He says the material has some explanation of the system and problem-solving.

mike · Post by **mike** » Mon May 09, 2005 9:38 pm

get them to me and I'll add them to the downloads section

Post by **jcslocum** » Tue May 10, 2005 12:26 am

Here they are on my web site. Feel free to download.

http://tinyurl.com/dbh7x

http://tinyurl.com/88olj

Good luck!

Post by **jcslocum** » Tue May 10, 2005 1:14 am

I did some mining with Google:

Spark Plug Warning:
Ducati recommend Champion RA6YC spark plugs for the 906 and according to NGK themselves, the NGK equivalent is DPR8EA-9, the Nippon Denso equivalent being X24EPR-U9. Ducatis fitted with Marelli Digiplex ignition systems seem to be quite fussy on the spark plugs used, namely they must be the type with a built-in resistor. i.e. NGK DPR8EA-9 and NOT DP8EA-9 where the "R" in the code means "Resistor". If you fit a non-resistor plug, the bike will run OK most of the time but will have the effect of cutting the ignition from time to time. If it happens, all you need to do is switch the ignition off once or twice and the Digiplex appears to re-set itself. This effect can happen if you have another electrical (non-ignition) fault with the bike.

Kokusan Ignition System: 21 Apr 2001 from: <louis@xn85.freeserve.co.uk>
Hi David, The Kokusan ignition happened to be on the bike when I purchased it. Service history shows it was fitted by Sports Motorcycles in Manchester - (known for prepping and supplying Mike Hailwood's TT winning 900ss). The Digiplex system has been removed completely. I am guessing here but I believe it uses the same pickup points as the 907ie - that is to say engine phase and speed with the pickups being inserted directly into the magneto side engine cover. Therefore I think that the flywheel needs to be replaced with a 750 type flywheel with 2 pickup points on it instead of the 4 required by the Digiplex systems and the 907ie.

On the 907ie and 906 engine there are already mounting points for the Kokusan ignition pickup plate. The existence of these mounting points came as a great relief to me when I transplanted the 907ie engine into my bike. The replacement Kokusan pickups are wired directly to some ignition units which then are connected to the coils and then on to the spark plugs. The ignition boxes and coils are mounted together on a bracket on the RHS of the bike just behind the radiator. The vacuum takeoffs on the carbs normally used by the Digiplex to measure vacuum, are blocked off with some plastic goo.

I think that the modifications would require a good knowledge of bike electronics to be honest the problem is that the although the wiring in of the Kokusan is quite easy I would guess unravelling and de-installing the old Digiplex system is harder. Benefits seem to be:

a) There is quite a bit of space under the saddle where the old Digiplex computer used to be.
b) The Kokusan ignition pickup critical distance from the flywheel is easily measured and adjusted.
c) Its relatively easy to advance/retard the timing using the plate to suit any special running requirements e.g. fitting a turbo, or say high comp piston upgrade.
d) No worries about upsetting the computer if suppressed spark plugs are not used.

I don't know what the drawbacks of the Kokusan implementation are - none I hope. As I said though I do seem to have to wait a while for the bike to 'clear its throat' after getting back on the throttle after a slow corner. Unfortunately I don't know which model the replacement kit came from, I know that the first model the Kokusan unit was fitted to was the 750 Paso, later it was fitted to the 750 Sport and maybe 900ss. All the best, Louis

Rodney · Post by **Rodney** » Tue May 10, 2005 7:14 am

check voltage at coils as i noticed on the circuit
diagram that there is a joint between the two coils this could be
a high resistance joint cuasing some of the problem also if the
voltage is below 10.5v at the coils you will start to have a problem
as you wont be generating enough spark to ignite the fuel.
one test i have done is remove one spark plug from the head
and shorted it out on the frame and then hit the starter to see if
it is producing a spark but be warned the motor will start on one cyclinder. another test is spray some aero start into cyclinders
through the spark plugs then reinsurt the plugs and hit the starter
if it fires then you have too low a voltage at the coils or a fuel
problem instead

Rodney · Post by **Rodney** » Tue May 10, 2005 7:26 am

:toofar: further to that i did notice that the same joint between the
coils also goes to the ingition stop switch and the other coil this
joint could be the root of the problem as it supplies power to the digiplexer as well as the coils

Post by **Skins** » Tue May 10, 2005 7:42 am

GO RODNEY!

ahdoman · Post by **ahdoman** » Tue May 10, 2005 2:03 pm

Rodney, Jon, Skins & Jose - I have officially enshrined you guys into my "Ducati Gods" hall of fame. I put the NGK DPR8EA-9 plugs in and have not had the "power down" problem any more (see "What the heck is wrong with my Paso - a challenge). For those of you who have the Magnetti Marelli systems; it does matter what plug you use! Don't use the non-resistor type. (B.T.W. - the local Ducati shop are the ones who installed the non-resistor type plugs when they did the tune-up).
Rodney - For those of us "yanks" - what is "joint" in the state side translation?

DucSoup · Post by **DucSoup** » Tue May 10, 2005 6:22 pm

I have pulled the fairings off the duc and this morning on the way to work, I stopped in and purchased a new battery. It is a West Co. Maint-free unit and I am going to enjoy not having to worry about that overflow tube ever again. It was a bit more expensive than if I had ordered from the web but there is no shipping, no hazmat fees and I help a local business stick around for the day I may need them

I also picked up two NGK resistor plugs. I have not had time to see what is actually in the bike now but they are cheap insurance and will not go bad on the shelf if I do not need them yet.

Now, If only I can find that multi meter....

Post by **Skins** » Tue May 10, 2005 8:16 pm

Good news, adoman ... but have you ridden for an hour or more non-stop to warm up the valve gear and rule out a problem there? (I really had my heart set on that steak dinner, you see). Joint = connection (where two or more wires join or connect).

mike · Post by **mike** » Tue May 10, 2005 8:18 pm

FYI I have added the 906 Paso wiring diagrams to the downloads section, so if youve got limited bandwidth, you can pull 'em from your site whenever.

thanks!

ahdoman · Post by **ahdoman** » Tue May 10, 2005 8:35 pm

Skins - Yep, I rode for a couple of hours and all seems well! It's amazing what happens when you don't pay attention to one little letter.

Jose · Post by **Jose** » Tue May 10, 2005 8:38 pm

Hola there are they all ...

I have been investigating and is encotrado this:

http://www.silent-hektik.com/ page56.html
xoomer.virgilio.it/ flmbe/Manualea.htm

Espero que se entienda.

JOSE