|Dennis Martin's Allazurra Ignition Fix
Here we go...................
The basic problem is short-circuiting of the two wires coming out of the pickup coil, where a small voltage pulse is generated, to trigger a spark. If you can find them, you could easily replace the coils. At least in my case, the short was in the lower coil.
Where the two wires exit the encapsulated coil, they are bent quite sharply to guide them away from the flywheel and the crankcase, headed up to where the wires for both coils exit the case. The wires are quite small, and the thin insulation is stretched at the bend. About 2 mm from where the wire exits the coil plastic, it cracks, probably due to the stretching of the insulation, caused by the bend, and to the constant hot oil bath it lives in, and probably some vibration too. The coil develops a small amount of residual magnetism, induced from the flywheel magnets whizzing by, and this attracts very small pieces of metal contained in the oil. These pieces are not very large, they look like sludge, but they are electrically conductive. When enough of these metal particles are collected at the pickup coil, they short the two wires together at the small cracks in the insulation, and off goes the spark to that cylinder.
In my bike, the problem was always in the lower pickup coil, probably because it is in a bath of oil when the engine is running. You can see the particles if you take the coil out carefully, they look like whiskers growing there. I never saw them on the upper coil. So here's what I did. I decided I didn't want to cut and joint the wires, because the crack in the insulation is too close to the coil casing to make a good seal, in my opinion. So I carefully took out and cleaned the coil unit with alcohol to remove all the oil, without disconnecting anything, then carefully cut back some of the "spaghetti tubing", and separated the two wires, especially where the cracks are. I formed them so they would exit at the right place, headed towards the exit hole, and out of harms way. I can't show you this- you'll just have to study the wire path BEFORE you remove the coil unit. The important thing is to separate them, all the way off the coil. I placed them about 2-3 mm apart.
Then, using fast setting two part epoxy, I put a glob over the insulation cracks, holding the wires against the coil so they would be supported when the epoxy set up, and of course they would be insulated from each other. After this set, I then "spotted" the wires in a couple of places to hold them in place to the coil as previously planned. When the "spots" set up, I then covered the whole area well with the epoxy, to in effect incorporate the wires into the encapsulation of the coil, being careful that they were placed correctly so the wires would not be bent where they exited the epoxy.
Then it was time for a cool beer until all the setting up was done, and re-assemble carefully the coil to its mounting bracket. When re-installing the pickup coils, make sure to set the coil to flywheel clearance very carefully, it affects spark timing. I used bronze feeler gauges, (Cal Custom) so you can feel the clearance better in the magnetic environment, set at .019 go, .020 no go. Then, just for fun, I did the other coil the same way, just in case. Finally, after both coils were done and re-adjusted, I carefully tied the wires to support them on their way out of the case, mainly to avoid the effects of vibration. BTW, I did this in the motel parking lot in Arkansas while my buddies were off riding the twisties!!
A heat lamp will help to set the epoxy quicker. You may find a better product than I used.
I was lucky in that I was able to remove the case cover without destroying the gasket, so I cleaned it with the alcohol and reset it with a small coating of Permatex High Tack - my favorite gasket sealer. I do not do silicone sealer if at all possible. If you do, be very careful to use a very small amount, so that there is none at all squeezed out when you tighten the screws. It will block oil ways, and does not dissolve in oil. If you do end up needing a new gasket, they are the same as any Ducati Pantah engine. A good dealer should have one.
No, you don't have to drain the oil, you will lose about calf a cupful, though, so don't do this on the living room carpet!!
One last thing. There is a plug that connects the pickup wires to the main wiring harness. If you follow them along, you'll find it. Mine was wrapped with tape and tied to the right hand upper frame tube. Make sure the plug/socket is clean and makes a good contact. Then put it all back together and wrap it again.
So there you have it. Sorry the story is so long, I hope it helps. As I told you, the fix has held two years and 20,000 miles so far.....I like riding my Alazzurra. Keep the rubber side down!
Postscript: I had the bike on its center stand. I'll bet that if you have to go in there again and you look carefully, there will be two tiny cracks in the insulation, just waiting to shut you down. In my case, the bike would go onto one cylinder, clear itself after a while, then do it again. I tried all the standard things, plugs, carb clean, swap ignition amplifiers, even bought a new amplifier, before I found the real culprit.........
One other thing that comes to mind to recommend to all: Next time you have the tank off for any reason, run a new ground wire to make certain the grounds are all connected together electrically, including the ground side of the battery. I used #10 insulated wire. Be sure to attach this same wire to the case of the voltage regulator, so it is positively grounded. In fact, don't wait for next time - do it today. Your wallet will thank you!!