Digiplex Ignition circuit board resolder

dave906 · Post by **dave906** » Tue Jan 30, 2007 11:45 am

Having some intermittent ignition problems with the Marelli Digiplex when it heats up after a few miles on the road. Having done the relay rewiring mods without completely solving the problem, I am planning on cracking open the Digiplex and resoldering the circuit board next to see if this corrects any dry or cracked solder joints. If this doesn't solve the problem then I'm getting out the English-German dictionary and speaking to Mr Silent Hektik.

The underside of the ignition seems to have a plastic panel that doesn't have any obvious way of removing it - ie no screws. Initial gentle prying with a screwdriver hasn't released it. It may be glued in place.
Before I start hacking away without knowing exactly how its put together or configured underneath the panel, have any of the people who have had their Digiplexes resoldered got any advice on how the panel is best removed? Any tips or photos on what to do and what not to do??
cheers Dave

Post by **paso750** » Tue Jan 30, 2007 2:05 pm

Dave,

sure that the heating up isn`t caused by any bad wiring or ground connections ?

Gerhard

dave906 · Post by **dave906** » Wed Jan 31, 2007 12:52 am

Hi Gerhard
Yes, I've been through the wiring and corrected a number of areas. At one stage in previous years, I even discovered the wiring in the kill/run switch just barely making contact with a single strand of the original wire. Those areas are sorted now. Voltage levels are good with engine off and while running. Earths solid.

I believe its time for Digiplex surgery. If anyone has ever come across the electronic schematic for inside of the actual ignition - say from a friendly source at the Marelli factory - that would be very useful also. Its a pretty old design now, so maybe they wouldn't mind releasing the factory confidential detail. Do any of our Italian members want to try contacting the factory to ask?

cheers Dave

persempre907 · Post by **persempre907** » Wed Jan 31, 2007 6:07 am

Have you checked the pick-up on the flywheel?
I had the same problem: when the engine was cold the bike used to work, but when became hot it first lessened strokes and then it switched off.
Ciao

JWilliam · Post by **JWilliam** » Wed Jan 31, 2007 6:33 pm

Try Bauke Meidema's electric relay mod to the ignition unit for one, and I recommend changing the fugin' standard ignition coils for Kawasaki GPZ500 units (greater primary coil impedance - preventing overloading of the ignition unit). Don't know how many times I've said that. The Digiplex unit bottom is glued on, work your way around the edge of this plastic underpanel but be careful not to penetrate the unit, just work off the underpanel. You won't find anything out of the ordinary, but all the components are covered with a rubberised waterproof sealant and it also has an EPROM chip so No BRIGHT LIGHTS. The main fault I have had with the unit is a misfire above 7000rpm, but this was stopped! by changing the ignition coils (see above). Apart from that I am not totally sure about the ignition mapping and I have read that the Silent Hektik module has a number of ignition maps, don't think you will need them unless you campaign it at your local racetrack. Your comment that it is OK until it warms up strikes a chord with the above mentioned coil exchange fix but if this is happening at low rpm then your ignition unit might already be past it.