Starting problem

discussions specific to the 906 Paso
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romus
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Re: Starting problem

Post by romus »

paso750 wrote:
In turn that means the spark isn't timing with the turn over, correct?
No, there´s no way the spark timing can vary. The pick ups get their signal from the flywheel which is mounted on the crankshaft which is turned by the starter. So no matter if the starter turns fast or slow the "firing signal" to the CDI unit will always be right or let´s better say as set by the pick up (bracket) position.

G.
okay, thanks. So when I put the new Digiplex on and got it going it hummed away nicely. It wouldn't do that if there was a coil spark issue would it? So, because of the clunking in the engine case when turning over to start - that's why I am thinking it's the sprag clutch, just not turning it over enough. Something I read says engine can clunk if backfire of starter motor. I'm trying to read to figure out what causes what.

The only thing I haven't done electrical wise is measure the output of the pick-ups, as you said (check pick-up/flywheel clearance and pick up bracket marks - if nothing was done to these parts this is not necessary). But, since I had not ever done anything to these parts, I have presumed not necessary to check. And before my start problems the battery was not running down.
Last edited by romus on Thu Jun 09, 2011 12:52 pm, edited 1 time in total.
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higgy
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Re: Starting problem

Post by higgy »

No, there´s no way the spark timing can vary. The pick ups get their signal from the flywheel which is mounted on the crankshaft which is turned by the starter. So no matter if the starter turns fast or slow the "firing signal" to the CDI unit will always be right or let´s better say as set by the pick up (bracket) position.
Not entirely true...In the digiplex of this vintage if the secondary resistance is off one way or the other internal timing signals can be out of sync causing a misfire. It is the nature of CDI, resistance is everything.
It is also the reasoning behind the preference for champion plugs for which the unit was designed :thumbup:

which are of course not to be found anywhere anymore :banghead:
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paso750
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Re: Starting problem

Post by paso750 »

ok, if that is so. I did not consider the Digiplex.
From the mechanical point of view it`s impossible.
What secondary resistance are you referring to btw and how is it a problem getting Champions ?
Maybe in the shop around the corner but just check internet shops or ebay.
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Re: Starting problem

Post by higgy »

The champion of old is different from what's out there now. Don't know what the difference is that prompted the new classification. I'm all ears tho :mrgreen:
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
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Re: Starting problem

Post by paso750 »

what do you mean by classfication, the renaming from YC to HC ?

R = radio interference suppressed
A = 12mm thread, 19mm thread length, 18mm wrench size (some tables say 16mm)
8 = thermal value
H = isolator projection 0,75mm (Y = isolator projection 1,5mm)
C = copper core electrode

I guess isolator projection means how long the electrode sticks out the isolator.
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higgy
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Re: Starting problem

Post by higgy »

was that the only change g ? I Have not bothered to look into in depth :mrgreen:
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
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Re: Starting problem

Post by paso750 »

got that from a german CHAMPION overview.
Here`s an english one
Image
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higgy
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Re: Starting problem

Post by higgy »

So if I'm reading this correctly the difference is the replacement plug extends 0.30 further than the old
I would think if that was a big issue someone would have posted it by now :thumbup:

Also worth noting that is the same average increase you would need when idexing a plug so the net result would be approximately the same as the original HC Make sense :?:
Now everyone rush out and get some indexing shims and Champions so all our 906's can run like the Ducati gods intended :mrgreen: :mrgreen: :mrgreen:

Image

Image

Image

Image
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
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Re: Starting problem

Post by paso750 »

while the 906 workshop manual says YC the user manual already says HC so Ducati knew of this change and edited the manuals accordingly.
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Re: Starting problem

Post by higgy »

jeez G, you read the manual in your spare time do ya :lol: :lol: :lol: :lol: :lol: :cool:

been out tracking down a new charging issue on the 907,found some newly chafed wires shorting to a frame gusset. Had a local constable stop me last weekend on my way to Ephrata for not having my headlight on,like he knew the year of the Paso( :shock: ) :wacko: Figured I better fix it. Bike ran fine just dead the next time I went to start it up when I got home for about the 3rd time now. Figured I'd take a look at the belts as well as I never checked them :choo: Now that I have an additional week before hitting the road if my wife lets me I plan to finish the 906 belts and jetting and maybe replace that burned up Michelin with another before the show on the 18th. Wonder how much I can get for a 6 year old almost new Michelin :twisted:
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
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romus
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Re: Starting problem

Post by romus »

Phew...Yihaa...finally got it going.

The last job was to replace the sprag clutch. There was some clunking that had developed during my starting efforts - probably was there before, but I didn't notice.

So, I put in a KTM part 58440026000, which is cheaper and equivalent to the Ducati part 70140011A. Bike started up like a beauty and is regularly starting no problems.

Seems I had multiple issues because from my work in an attempt to get it started I found some wire connections badly in need of repair, a Selonoid that seemed to need replacing and I got a replacement CPU after they tested it and said it was shot.

Okay, that took me a long time, but I sure moved up in my learning curve understanding on the electrics and starting components :-). Basically my electric side has had a thorough overhall.

P.S. Sprag clutch KTM part 58440026000 can be got for 66.45 pounds, which includes freight from http://www.speedaway.co.uk. On their site it is under FREE-WHEEL FWD 332008 BLS (58440026000). That was the cheapest I could find to Australia. You will read on-line that it goes on backwards for the Ducati. That's easy to see - one side has a left directional arrow the same as the Ducati one (facing you as you look at it when it is in). So, that side is put in the same as the one you take out. There is a KTM circlip you take off the back and I used the original Ducati circlip (thicker) to put it back in.

I used a heat gun to get that crank shaft bolt off and when putting it back together - Loctite 648 and a replacement alternator gasket.

Some ueful links were:

http://www.mad-ducati.com/ShowPage2.php ... lutch.html

http://www.perthstreetbikes.com/forum/f ... tch-85481/

http://www.mad-ducati.com/ShowPage2.php ... over2.html

http://www.apriliaforum.com/forums/show ... p?t=155882

http://faq.f650.com/FAQs/SpragClutchFAQ.htm

http://forums.ducatipaso.org/viewtopic.php?f=1&t=705
Warwick - on a learning curve and on a
Ducati Paso - Soul of a thoroughbred :P
Mc tool
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Re: Starting problem

Post by Mc tool »

Where do I get these "indexing shims" from , nobody round here has heard of them , they all thought I was mad
I wish I was young again............Id be heaps smarter than last time
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higgy
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Re: Starting problem

Post by higgy »

go karts use them all the time or you can order them directly from champion


Moroso also carries them and Accell
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
Mc tool
paso grand pooh-bah
Posts: 1874
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
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Re: Starting problem

Post by Mc tool »

:P :P :P :lol: :lol:
I wish I was young again............Id be heaps smarter than last time
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