rich running

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Scottish888
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Location: Edinburgh, Scotland UK

Re: rich running

Postby Scottish888 » Sat May 09, 2020 12:24 pm

I spent a long time getting the upper (and lower) bevel mesh correct but I'm sure the dots all lined up at the correct time, no harm to check again.
I have now set the static timing at 37 btdc using the top notch mark, that makes the dot about 3 o clock. I think that is where this machine has its timing mark, the top.
Will hopefully start it later, it is much more advanced now than previous setting and hopefully in the range.
Pic is the timing at 37 deg BTDC using top mark

Regards
duc ign 37 deg.jpg
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Duccout
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Location: Essex UK

Re: rich running

Postby Duccout » Sat May 09, 2020 1:09 pm

It has been known that the dots on the bevels are wrong, leading to inaccurate valve timing.

ducwiz
Posts: 604
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Location: near Frankfurt, Germany

Re: rich running

Postby ducwiz » Sat May 09, 2020 2:27 pm

Hi all,

I just remembered having written posts in an earlier thread about the set-up of the Ducati CDI, and discovered it:
http://www.motoscrubs.com/forum/viewtopic.php?f=3&t=2866&p=21385#p21385

Could be helpful once more.

Hans

Ventodue
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Location: Montpellier, France

Re: rich running

Postby Ventodue » Sat May 09, 2020 3:19 pm

Ventodue wrote:
Scottish888 wrote:<snip> Could anyone post a pic of a properly timed Eletronica system so I can see where the timing mark is at TDC?

Will try to get it done later today - 450 SCR, btw.

As promised ;)
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Ventodue
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Location: Montpellier, France

Re: misfiring

Postby Ventodue » Sat May 09, 2020 3:27 pm

Scottish888 wrote: "So the spark is advanced gradually as the speed increases."

That's pretty much all you need to retain from that description ... :D . It might help, however, to add the words,"'and automatically" after 'gradually'.

Scottish888 wrote:The Haynes manual refers to an air gap between pickup rotor/stator air gap, but fails to say if it can be adjusted. Can it?

Nope.

(Well, of course it could be. But it wasn't designed to be adjustable).

Ventodue
Posts: 952
Joined: Mon Mar 08, 2010 3:23 pm
Location: Montpellier, France

Re: misfiring

Postby Ventodue » Sat May 09, 2020 3:57 pm

Scottish888 wrote:<snip> When riding it today, it almost felt like a switch, 5000 rpm, open it up and just occasional firing, close the throttle and it comes to life at 5000 or less.

It does occur to me that this could be a break down in the pick-up (having had one go south many moons ago, I know there is more than just a pulse generator/coil in the pick-up, btw. Got mine re-built by West Country Windings. It was a resistor or a diode that had died, I seem to remember).

Your best test is by replacement. But that's easier said than done, I appreciate. Any one got a spare pick-up they could send our Scottish friend to try? I may have - will have to go look. But the postal service from here (France)is currently pretty rubbish, so I'm probably not your best option :?

Ditto the transducer box. They're the same as used on the twins, if you didn't know already. Remakes are available, or ebay can be your friend - altho' the only seller I could find currently in the market seems to have a grossly over-inflated idea of their value ... :roll: :?

Craig

Scottish888
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Location: Edinburgh, Scotland UK

Re: rich running

Postby Scottish888 » Sat May 09, 2020 4:32 pm

Ventodue,
Is that photo of your stator when it is at TDC? or is that the 37 deg BTDC position?
The ign was retarted a bit so now timed exactly to 37 BTDC using the notch and the upper alignment mark on the backplate which is highlighted in white as in the pic. I first got TDC on firing stroke, used a 0-40 deg template with a 37 deg line that fitted within the ign housing, I turned the engine back 37deg from TDC and lined up the white mark on the ign backplate with the notch. All good.
Having looked at Ventodue's ign pic I noticed it was 180 deg our from mine, sure enough the rotor can be fitted both ways?!
I did try it the other way around but it only back fired and would not start, so really only one way for that to fit and work on my bike.
Changed the plug gap back to 0.8mm and took it out for a test, just the same, actually more misfiring even at lower revs. Plug looked good, no soot.
Looks like a transducer, will get check on ebay etc.
Hans, I tried to get the strobe going but could not pick up any pulse, used a car battery and earthed that to the bike also. Mabe the new ign lead is just useless for strobe pick up, will try changing the plug lead.


Regards

Ventodue
Posts: 952
Joined: Mon Mar 08, 2010 3:23 pm
Location: Montpellier, France

Re: rich running

Postby Ventodue » Sun May 10, 2020 11:05 am

Scottish888 wrote:Is that photo of your stator when it is at TDC? or is that the 37 deg BTDC position?

Nah,that photo is just of where the engine stopped ;) . Apologies, my bad: I missed your, " ... so I can see where the timing mark is at TDC". But no matter .. I can confirm that the dots were originally lined up at +/- 38 BTDC, and I hope you can see the similarity of position with your own.

Scottish888 wrote:The ign was retarded a bit so now timed exactly to 37 BTDC <snip>

I believe your bike is a 250? Well, here's something which you might like to consider.

This is from the Italian version of the owner's handbook for the post-1972 bikes fitted with the Ducati Elettrotechnica ignition. Italian first, English translation afterwards (also see the attached scan).

"Ruatore l'albero motore in senso orario fino ad ottenere un valore di anticipio prima del PMS di 54° per le 250; 42° per le 350; e di 36° per le 450."

"Rotate the crankshaft clockwise in order to obtain an advance value BTDC of 54° for the 250s; 42° for the 350s; and 36° for the 450s".


Now, I have not seen these differing values given anywhere else, not even in Massimo Clarke who is my usual 'Go-to' reference. Normally, it's always '36-38, no mention of engine size'. But, but, but ... There it is, in black and white, in a booklet published by the manufacturer: different engine size = different static advance. And hey! The contact breaker ignition is set up differently according to engine size. So why not the electronic?

So, even tho' I'm not convinced that your problem is caused by the static timing being out, it might be worth setting it to the value above?

Scottish888 wrote:Changed the plug gap back to 0.8mm

That is correct for a Ducati Elettrotechnica ignition.

Scottish888 wrote:Looks like a transducer, will get check on ebay etc.

The transducer wouldn't be my first suspect - as previously, I'd rather go for the pick-up. (The weak point in the transducer is the thyristor/SCR, and these tend to have a 'Go/No Go' mode of failure).

However, it's true that the transducer would be the easier bit to obtain on a 'swap to see' basis. I know I have a spare, if no-one in the UK can help. Best to ask for one from a 860 - tend to be easier to find :)
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Duccout
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Location: Essex UK

Re: rich running

Postby Duccout » Sun May 10, 2020 11:18 am

Would it be possible for someone like Rex's Speed Shop to test the pick-up and transducer? Or even modify them?

Scottish888
Posts: 266
Joined: Wed Feb 07, 2018 1:47 am
Location: Edinburgh, Scotland UK

Re: rich running

Postby Scottish888 » Sun May 10, 2020 12:04 pm

Thanks guys,

All the work I have done so far has had no effect, I agreee that the timing being out a bit would not stop running beyond 5000 rpm, It is misfiring on the way up to 5000. The only clean part is around idle speed.
The pickup on the red plastic backplate looks ok, no cracks in the potting, they are just steel plates according to a moto morini site, what could go wrong with that?
Finding another pickup could be very difficult so it may be worth converting to points if I can source the parts.
If I convert to point i guess I just need to replace the transducer with a 6 volt coil
I see a lot of new similar transducer/coils for fantic and other trials bikes around 40 euros but they are for 12 volt I guess, would it be possible to these in a 6 volt system?
https://www.ebay.co.uk/itm/ECU-Coil-Duc ... Swy6hccAO7.
It would be very helpful to be able to test the pick up and transducer functions but I think there is no info out there on this.
Looks like a points setup would be more reliable with zero mystery Ducati electronics.
Thanks again for helping with good advice, always much appreciated.

Regards,

Alex
Last edited by Scottish888 on Sun May 10, 2020 1:32 pm, edited 1 time in total.


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