Are trying to wake up my F1 after a couple of years in the garage. But are facing some issues.
Have adjusted the valves to correct values. Have cleaned the carburettors, new gaskets, needles and seats etc. Float hight is correct. The engine have spark and started a couple of times during winter. Not running, just starting to check for ignition. Worked OK.
Now, with fresh fuel, warm weather etc its dead. Was convinced it was the carburettors since I had spark, but not so sure anymore.
Today I checked the ignition. So I grabbed the multimeter and wandered into bike electrics, an area I do not know much about.

The pickups read 220 Ohms. So that should be OK.
I noticed that my ignition lamp would not blink on the front cylinder. If I use a loose spark plug grounded to the engine, it would blink, but not if connected to the plug in the cylinder. So I checked the coils since I suspected the spark is to week in the compressed air:
Nippon Denso 029700 Coils (early type ignition system)
Rear Cylinder: LT 4,5 Ohm HT 14.6K ohm
Front Cylinder: LT 4,4Ohm HT 131K ohm
I guess the front coil is gone, and the rear has a higher resistance that I was expecting (8,8K ohm according to manual)

What to do now?
The bike is for "Sunday driving" and street/city use, so the 5.0 Ohm Dyna coil is maybe a good option (the best?), since heat is an issue with the 3.0 Ohm.

What about the Bosch ballast, should this be removed if fitting Dyna coils(or other)?
What does this ballast do? (Yes, I have no clue..)

No input? I need som help here...

I am no help on electrical.....but it seems like you would get some snap crackle pop from the motor if only 1 cylinder is sparking. I have had BMW and Nortons that would even start on 1 lung. I think I would go back to basics first, fresh plugs, fresh battery and clean terminals, ensure fuel flow and fresh gas. Then start the more sophisticated trouble shooting.

I've had a long and good history with Dyna coils, and they have good tech support for your questions, over the phone even.

Well, I have established that one coil is gone, and i'm unsure about how the other performes "under pressure" . So I think the best way is to get two new identical coils, since I must change one. When they are hooked up and I get a nice and fat blue spark.... I can see if that is what it takes to fire up. If not I have to keep on testing.

I think i'l take the change on ordering two 5 ohm Dynatek coils.

On my 36mm Dellortos I have 1,5 turn out on the air mix, and lifted the sliders about 1,5 turn from closed. It should be in the ballpark to get it running, should't it?

Hello Desmo. It would always help if we knew which F1 we are talking about; the early one with small valves and large plug, or the later one with large valves and small plug. Stiil, at least three different coils were used. I did not know any F1s came with ballasts on the coils; have only seen on the Pantahs and Cagivas with Motoplat coils. Since I thought ballast was to add weight (joke) I have always tossed them; it seems not to matter.

Dyna coils are certainly an upgrade, but they are not bolt on. As an alternative you could buy some good used black stock coils found on the two-valve engines starting around 1999 and later into the 2000s --- the ones still being used with Kokusan igniter boxes. They are 5 ohms, and will fit right in (not so with the Dynas). Really cheap off ebay!

One and one quarter turns is a good start on the small screw, try for about 1100 Rpm with the big one.

Good luck, MikeV

As usual, MikeV has most likely given the best advice. The later version of the Dyna coil, like the one I recently got for my Norton Commando, might be easier to mount up than the original version. And Ed Milich (ed@ducpower.com) might be a good source for the Ducati coils Mike mentioned.

http://www.ebay.com/itm/Dynatek-Dyna-Ignition-Coils-Coil-5-ohm-Dual-Output-DC7-1-/400359247116

My F1 is a "franken1". It is a F1B with serial number 00683, but at some stage the 750 engine has been swapped for a 82-83 (SL?)DM600 engine. I think the ignition is the standard early F1B (gray Nippon Denso 029700 Coils and Bosch ECU). If I recall correct the Motoplat coils are from S/N 001505 or around there.

While I gather parts to build a 750 engine, I need to get the 600 running. It's a nice engine.

will the california cycleworks exactfit coils fit?

I did order the Dyna 5ohm coils I mentioned in an earlier post, and now they have arrived at my pick up point. So have to do some work on the bike during the weekend. How about the Bosch ballast that was in front of the ND coils. Should I skip those and take current directly from ECU to the coil, or keep them. Still don't know what they do...