32mm PHF Dellorto stock specs for needle and jets?

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stian buksa
Cucciolo - the Lil Pup
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change of coils

Post by stian buksa » Thu Aug 12, 2010 4:49 am

A bit out of topic maybe, but...

When you change coils what kind of coils do you change to ?
I've been looking at high output coils, the kind Steve sells or car HO coils, but I'm afraid that the alternator wont handle the higher power consumption. Its all ready struggling at low rpm with lights on

And do you need to fit condenser(s) and ballast resistor(s) ?


Stian, Norway

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Steve Foster
Parallel Twin
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Post by Steve Foster » Sat Aug 14, 2010 3:09 am

Hi Stian, rather than trying to answer your questions directly I suggest that you refer to the classic article about this written by Gordon Jennings in 1977 in Cycle magazine.

See: http://www.ducatimeccanica.com/articles/coils.html

Regards, Steve.
1974 Ducati 750 GT

Grover
Parallel Twin
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Post by Grover » Sat Aug 14, 2010 2:04 pm

Steve, that is one very interesting aticle.
The older we get, the more toys we collect!!!

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Steve Foster
Parallel Twin
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Post by Steve Foster » Sun Aug 15, 2010 4:14 pm

Sure is Grover, and there is a related article which I forgot to mention called "Ballast Resistors Understanding how they work - Lloyd Maclean" at http://www.ducatimeccanica.com/ignition_follow_up.html.

Cheers, Steve.
1974 Ducati 750 GT

stian buksa
Cucciolo - the Lil Pup
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Post by stian buksa » Tue Aug 17, 2010 8:44 am

I've read the article, and it is really interesting. But as it is from the mid 70s I wonder if modern coils still need a ballast resistor and condenser(s) ?
I see in the follow-up article that one ballast resistor is sufficient

I also wonder if the standard charging system can handle the higher power consumption as I really don't want to solde and grind the timing cams as suggested in the article

Would be cool to hear from someone who has done the change


Thanks


Stian

wdietz186
Cagiva Alazzura
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Post by wdietz186 » Wed Aug 18, 2010 11:30 am

The setup I would recommend is the Dyna electronic ignition and coils. I believe Steve has them listed on this site. I've used the system for the past 20 or so years and it is trouble free.The only hard part of the install is lifting the distributor housing and moving the drive gear 1 tooth[I don't remember if it was advance or retard,but it is covered in the instructions] As for current draw I don't think it is much greater than the stock arrangement.The trick is to use the lights as little as possible and keep the revs up or upgrade the alt. rotor.

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Steve Foster
Parallel Twin
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Location: Sydney, Australia.

Post by Steve Foster » Wed Aug 18, 2010 5:16 pm

The only hard part of the install is lifting the distributor housing and moving the drive gear 1 tooth [I don't remember if it was advance or retard,but it is covered in the instructions]
I've heard this about moving the drive gear 1 tooth before somewhere but the installation instructions that I received with my DS4-1 kit didn't make any mention it (and I haven't installed it as yet). See: http://www.dynaonline.com/skins/downloa ... /DS4-1.pdf
http://www.powercommander.com/downloads ... /DS4-1.pdf

Anyone got any further info about this or any other aspect of installing the Dyna ignition on a roundcase?

Thanks, Steve.
1974 Ducati 750 GT

machten
MHR / S2
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Post by machten » Wed Aug 18, 2010 7:04 pm

There's some more installation details on this site somewhere (or there used to be) that Steve includes (or did with mine) when you buy one from him that are well worth a read. I use Dyna ignition in my Sport and GT, and it is a real good thing - set and forget. I have used my original Ducati coils and have had no problems at all, but I guess newer coils are likely to better than old ones.

I know I had to move my GT distributor more than one tooth, but that may have been because it was in the wrong place to start with. In any case, it's not hard to work it out, you just need to mesh it so that you finish up approximately in the middle of the points plate adjustment holes at 10 degrees BTDC. You only need very small movements of the plate (as with points) to make significant timing changes.

One thing that I think is worth doing if you are fitting a Dyna to a running bike and have the timing equipment is to check your timing advance is working correctly in the first place so you don't get led down the the garden path if you have other problems. As the Dyna uses the existing bob weight and springs for timing advance, it will be relying on it. If it has a problem (uneven advance etc), you might as well address it now. If there is no problem, it is still worth giving the advance assembly a clean and lube, because once properly set up, you're not likely to be messing with the distributor for quite some time.


Kev

notanumber
Mariana
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Post by notanumber » Thu Aug 19, 2010 4:08 am

wdietz186 wrote:I do feel I must jump in and defend Rays assertion as to the slides on Bevels.It does help and it helps alot. Most all the 750's and 860's I have dealt with have had a dead/flat spot right off idle even when fitted with the stock air filtration setup[Anyone remember riding a bike with those?]
Fiddling with the mixture screws,pilot jets, and to some extent the pump will lessen the symptom and most just accept it as an idiosyncracy of the bike and ride around it.But the richer mix provided at 1/8 + throttle the 60/1 slide provides improves the tractability 100% I've used them in my bikes for 30+ years.
Your reference to the "dead/flat spot right off idle" sounds like a fairly familiar characteristic that I had always regarded as 'normal', happening only at very small (only just off idle) throttle openings intended to make power uptake as smooth as possible - if it's whacked open, no such problem. Is this a slide 'issue' then?

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