rough running (it's ignition!).

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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higgy
paso grand pooh-bah
Posts: 3327
Joined: Tue Jul 29, 2008 9:50 pm
model: 907 I.E.
year: 1992
Location: Hilltown,Pennsylvania
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Re: fuel pump, rough running.

Post by higgy »

Sounds electrical to me, especially with the flaming backfire :thumbup:
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
GuinnessDave
Posts: 31
Joined: Mon Mar 03, 2014 1:29 am
model: 750 Sport
year: 1990
Location: Savannah, Georgia, USA

Re: fuel pump, rough running.

Post by GuinnessDave »

Ok brothers, narrowed my cutting out to the ignition. No brainer probably, but, it seemed like that. Anyway, cleaned all contacts going to digiplex. Checked resistance to what I thought was the flywheel pickup, which was 770 ohms. One manual said 220 ohms and the other 150 maybe? The manual shows dual pickups, but, mine only has the single attached to the case cover. Is there a way to check air gap to that pickup? If so, it escapes me an my friend who is really the brains behind my troubleshooting. It's happens under hard acceleration mostly, it totally cuts out, then fires right back up, blowing a flame of unburned fuel out the pipes. The probably is keeping me from selling it and it's getting to the point of wondering if I need a new digiplex. Is it worth switching to Kokosun? Is one better than the other, and if so, what does the swap entail?

Thanks in advance. This bike will make a mechanic out of me yet.
User avatar
higgy
paso grand pooh-bah
Posts: 3327
Joined: Tue Jul 29, 2008 9:50 pm
model: 907 I.E.
year: 1992
Location: Hilltown,Pennsylvania
Contact:

Re: rough running (it's ignition!).

Post by higgy »

Sure your charging system is working ?
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
GuinnessDave
Posts: 31
Joined: Mon Mar 03, 2014 1:29 am
model: 750 Sport
year: 1990
Location: Savannah, Georgia, USA

Re: rough running (it's ignition!).

Post by GuinnessDave »

Checking it. Going to try the ignition relay mod. In the ignition switch, we found a voltage drop from 13V to 11V on one wire. That does not sound like a design feature.
GuinnessDave
Posts: 31
Joined: Mon Mar 03, 2014 1:29 am
model: 750 Sport
year: 1990
Location: Savannah, Georgia, USA

Re: rough running (it's ignition!).

Post by GuinnessDave »

looks like I got it going again strong. Put a relay to bypass the ignition switches. All hail to the forum!
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