Darmah already at 16 degrees ignition advance at 1,000rpm.

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mcinj
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Darmah already at 16 degrees ignition advance at 1,000rpm.

Post by mcinj »

I recently purchased a Brancato degre wheel from Steve and when checking the vertical cylinder, the advance was as adertised going to full advance at some 3,000RPM. On th horizontal cyclinder the advcance at 1,000RPM is 16 degrees, this goes to full advance at 1,500. I have tried different Bosch boxes and even interchanged two extra boxes with the other side. All three work perfectly on the vertical cyclinder. Checked ground on all boxes all good. Can this possibly be a pickup rpoblem? I don't see anything else in the circuit that could do it. I'm running Dyna Green coils, with no resistors. Pick up resistances approx. 240 ohms each
This is the last thing prior to putting the bike back on the road HELP!.
Bruin
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Post by BevHevSteve »

Suggest you switch the wires around on the pickup for the cylinder going full advance at low RPM....
Last edited by BevHevSteve on Mon Aug 30, 2010 1:47 pm, edited 1 time in total.
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mcinj
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Darmah 16 degrees advance at 1,000 RPM.

Post by mcinj »

Steve:
Thanks for your prompt response, I've tried that, and got the textbook full advance at idle RPM. No one that I have queried has ever seen this. It appears that the total advace curve encompasses about 16 degrees starting at 16. It stops at 3,000 RPM regardless of how high above that I go. The pickup wires have been replaced and "Potted" with JB weld. Could it be an airgap problem in your experience? Doesn't look as if the pickups have been mechanically disturbed. Anybody out there with experience with SACHES LED ignition? (Getting desperate as you can tell).
Bruin.
mcinj
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Darmah 16 degrees advance at idle.

Post by mcinj »

Just pulled the clutch cover and note a witness mark on the reluctor and on the inner pole of the lower pickup coil. It appears that the gap is too small. I'm thinking of either grinding the pickup pole or moving it out slightly, Can someone advise the actual gap required? Would also be interseted in other's experience with this problem.
Regards Bruin.
mizike77
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Post by mizike77 »

Moving the pickup in question around will change the timing advance. Have you taken the clutch cover off recently with this problem occuring after re installing it? I personally have attempted to take the clutch cover off and accidently loosened the pick up plate, therefore screwing up my adavnce. The plate can be moved without removing the clutch cover. Just remove the starter cover and that gives you access to 1 pickup plate bolt. You can loosen thet bolt and play with the advance a bit. The only real advantage to this is all your oil doesnt drain out like when you remove the clutch cover. The disadvantge is that the upper pickup will move more than the lower one, since your only loosening the upper mounting bolt.
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machten
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Post by machten »

I have no experience with SACHES ignition, but on any magnetic electronic ignition system, your base timing point will be determined by a combination of your pickup rotational position and your air gap. The electrical induction power in EDI systems is proportional to the square of the gap between the pickup and the magnet, so it is very sensisitive to the air gap. (having said that, it's bloody sensitive to rotational position too - have a look at the Bosh pickup position tool!).

What model are we talking about? It sounds like you have Bosch ignition "upstairs" but have changed it "downstairs". Why? Bosch is a good system.

Kev
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Post by wdietz186 »

You need to dig up somone with the pickup adjusting tool.You could try adjusting the air gap with the top bolt or moving the pickup on the mount plate.I think the air gap is supposed to be about .010" the spec is refered to in the Darmah service manual available in the Manuals Index. But without the tool you are just groping in the dark. You might try to get in touch with John Long,he has a shop in Miami and long experience with Ducati.
mcinj
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Post by mcinj »

I would rather not disturb the wiring loom by totally detaching the cover, I am tentatively thinking of attaching a dial test indicator to a spindle in the outrigger main bearing in the cover. With the vertical cylinder working correctly I may be able to make a comparison with the horizontal cyclinder pick up. If I fail, there is always Malcolm in Tampa.
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Post by machten »

Oops! Steve Foster has just brought to my attention an error in my last post (Thanks Steve!). I said..
The electrical induction power in EDI systems is proportional to the square of the gap between the pickup and the magnet
As Steve pointed out, I should have said:

The electrical induction power in EDI systems is inversely proportional to the square of the gap between the pickup and the magnet. ie the further away, the weaker the field.

The dangers of posting stuff while indulging in a few glasses of red!


mcinj,

the other thing worth checking is that the metal poles in the pickup sometimes come loose in the plastic mounting allowing a variable air gap, often resulting in the pole touching the magnet. There should be no movement in them at all. One of mine has required some Araldite epoxy glue to refix it in position and I've seen quite a few like that.


Kev
mcinj
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Post by mcinj »

Kev:
Thanks for your tip regarding loose poles in the pickup, after yelling Eureka at the top of my voice, I deployed to the garage and tried to wiggle the offending pole which was noticeably further out than the one on the other pick up. No wiggle, but a large pair of pliers moved it in by a finite amount which I did not measure. A drop of JB weld and we'll give it a try at the weekend. Once again thanks
Bruin.
machten
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Post by machten »

Best of luck! I'm not sure if that can produce the symptoms you are seeing, but worth checking and trying anyway, I guess. Let us know how you go.

Kev
mcinj
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Post by mcinj »

Just tried out the ignition timing on the Darmah, it had been some 16 degrees before TDC at idle. Kevin from Perth Australia suggested that the pickup pole might have moved out. this possibility reinforced by by a witness mark on the reluctor and the underside of the pole piece. I pushed the pole back in, epoxyed it in place and re-checked the timing Voila! the timing on both cylinders is as advertised. This is an insidious problem, which needs a timing wheel to detect. The bike still runs, but does not idle smoothly. Thanks to Kev for the advice about the poles, Tony Brancato for the timing wheel and Steve for stocking and selling them.
Not to forget Malcolm at Syd's, for listening to my daily tales of woe and supplying two pickup boxes to try.
Thanks again Bruin.
machten
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Post by machten »

Good news, Bruin!!!

Well done with your persistence in resolving this frustration. The further good news is, with the Bosch ignition set up, you shouldn't have to touch it for a long time.

Now get that sucker back on the road and give it the thrashing it deserves. (after it's run in, of course)!!!

Kev
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Post by jannypan »

I'm thinking of either grinding the pickup pole or moving it out slightly, Can someone advise the actual gap required? Would also be interseted in other's experience with this problem.
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