1988 750 Paso Loosing Spark

discussions specific to the 750 Paso

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angelix
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Re: 1988 750 Paso Loosing Spark

Post by angelix »

Sometimes we take for granted simple things... like plugs or connectors...

IF you replaced loom, CDI boxes, plugs (yes plugs, one time I got crazy with a set new out of the box...) and pickups, then the only thing that remains is connections.

I would suggest there is a connector not right or a simple loose ground.

One thing you shoud do is to replace like for like each of the componente one at the time making sure you thake them OUT from a WORKING BIKE.

AHH yes, I forgot, the KEY SWITCH, in the Paso I restored it wass "loose " and because of this mi digiplex burned; The kokusan mudules are much more resilient, but if the switch contact is not good it might result in misfiring.
nickta
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Re: 1988 750 Paso Loosing Spark

Post by nickta »

An out there question, but do you have access to an Oscilloscope or a friendly TV Repairman who would help out? Not something most would have in their Toolbox I admit, but 5 minutes of back probing would find where the signal gets lost in the system.

Cheers.

Nick.
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paso750
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Re: 1988 750 Paso Loosing Spark

Post by paso750 »

did you get it fixed ?
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higgy
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Re: 1988 750 Paso Loosing Spark

Post by higgy »

AHH yes, I forgot, the KEY SWITCH, in the Paso I restored it wass "loose " and because of this mi digiplex burned; The kokusan mudules are much more resilient, but if the switch contact is not good it might result in misfiring.

x2 :beer: :beer: :beer:
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If it ain't broke keep fixin it till it is
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a330us
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Re: 1988 750 Paso Loosing Spark

Post by a330us »

Hi, just finished re- reading this topic and was wondering if there was ever any fix for his problem found and posted? Thanks Arch.
Tootall
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Re: 1988 750 Paso Loosing Spark

Post by Tootall »

Problem Solved!
I took over this project from the OP in the Spring of 2015. To be quite honest I would have followed the same sequence of troubleshooting, but I wouldn't have added ground wires.Once the bike was in my shop,I went ahead and rechecked all the same stuff, with the same results. The bike was still losing spark on the forward cylinder when revved up. Ok so here is what I did.
1- I was suspicious of the wire harness. I built a new harness for the coils and for all the wiring under the seat . I replaced the pins in the multi connectors with new OEM type pins. I removed the extra grounds that the OP had added. Now I started the bike and to my displeasure it was still losing spark!
2- I looked again at the pulse generators or pick ups. They tested with an ohm meter within specs for resistance. However the metal tits were somewhat worn down and the wires although intact didn't look that great.
3- I found a pair of new pulse generators from a seller in the UK. I installed them and immediately the bike ran perfect on both cylinders!
4- This bike is fixed ! The moral of the story is that even though the pickups checked good with a meter, they were still bad. I believe it was the wear on the metal pickup contacts causing the problem. Even with the correct air gap to the rotor being wore out, it surely has an affect on proper operation. Or it may have been a combination of the contacts and the wires coming from the pick ups. It is possible that heat had degraded the very fine wires that come out of the pickups. The metal contacts weren't worn flush , but were probably 50 percent of what new ones look like.

In any case the bike is fixed, I'm happy and the owner is very happy. I hope this helps someone as it almost drove me to insanity as well!
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paso750
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Re: 1988 750 Paso Loosing Spark

Post by paso750 »

thanks for the update. It`s always good to know how a problem was solved.
It`s very rare that the one who solved the issue registers and posts and not the owner :thumbup:
Wear on the metal pick up would mean that it touched the flywheel in which case it should show some marks, too.
jhons
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year: 1987
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Re: 1988 750 Paso Loosing Spark

Post by jhons »

Buongiorno a tutti , sono un felicissimo possessore di una ducati paso 750 , anno 1987 . Ho un problema con i pickup , sono rotti e li devo sostituire , ma finora non sono riuscito a trovarli . Sapete dirmi dove posso comprarli ? Ho provato a chiamare ai vari concessionari ducati ma non ne hanno . Ho provato su ebay , ho trovato questa inserzione http://www.ebay.it/itm/1-pickup-zundgeb ... 0690718980 , ma mi hanno detto che la resistenza è di 400 ohm , mentre il meccanico mi dice che deve essere di 200 ohm . Ho letto anche che qualcuno ha sostituito tutto l'impianto elettrico , sapete dirmi cosa devo cercare e dove ? Grazie a tutti !!!
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paso750
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Re: 1988 750 Paso Loosing Spark

Post by paso750 »

io ti avevo già risposto l'ultima volta
jhons
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Re: 1988 750 Paso Loosing Spark

Post by jhons »

Scusami Paso750 , non avevo letto la risposta , non so' usare molto bene i forum .
Ho parlato con il meccanico , mi ha detto che ha fatto tutte le prove , ha cambiato le pipette , le candele , le bobione sono a psoto , il problema sono i pickup . Quello che non funziona è l'anteriore , il cilindro rivolto verso la ruota anteriore . Mi ha detto che l'unica soluzione è trovare i pickup con una resistenza si 200 ohm .
Grazie e ancora scusa per non aver letto la tua risposta .
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paso750
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Re: 1988 750 Paso Loosing Spark

Post by paso750 »

Ciao. Scusa, ma hai provato fare tutto quello che ho detto?
jhons
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Re: 1988 750 Paso Loosing Spark

Post by jhons »

Ciao Paso ,
si , con il meccanico abbiamo provato , abbiamo invertito le bobine , ed il risultato è che un pickup non funziona . Solo che non riesco a trovare dove comprarlo .
Grazie per l'interesse .
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paso750
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Re: 1988 750 Paso Loosing Spark

Post by paso750 »

ok, avete invertito le bobine. E le candele e i moduli d' accensione? Di quello che capisco hai comprato altri pick-up. Uno o tutti due?
Se anche con i pick-up nuovi il problema e rimasto l'uguale (cioè che il stesso cilindro non funziona) spendere dinuovo €200 per altri pick-up non cambierà niente perche il problema e un altro. Ma mi sembra che siete fissati su quello.
I pick-up li trovi al concessionario Ducati. Il numero 036946260 non esiste piu cosi dovrai prendere 400520253 che sono i pick-up usati sulla 900SS, Monster, Cagiva Elefant etc.
Quelli li trovi in Italia o da Stein Dinse in Germania.
jhons
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Re: 1988 750 Paso Loosing Spark

Post by jhons »

Ciao Paso ,
abbiamo invertito tutto , ma funziona sempre un cilindro . Ho comprato due pickup , e dopo averli montati , non funziona nessuno dei due , quindi un pickup è rotto , almeno penso così . Grazie per il codice del pezzo , li mando a prendere e ti faccio sapere , grazie mille !!!
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paso750
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Re: 1988 750 Paso Loosing Spark

Post by paso750 »

scusa avevo capito che anche con i pick-up nuovi funzionava solo un cilindro (come prima). Se tutti due non funzionano la situazione è una differente. Sei sicuro che non avete invertito i cavi dei pick-up? Non parlo del cilindro verticale e orrizontale ma di ogni pick-up. Se inverti i pick-up c'è la scintilla di accensione ma nel momento sbagliato e la Paso non va in moto. Se inverti i cavi di un pick-up il pick-up non funziona. Non c'è la scintilla di accensione.
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