Late 900GTS Wiring Diagram

[sdprice50]

Hoping someone out there can help me.

I have a very late (1979) 900 GTS. A previous owner had removed the wiring loom and most of the switches and lights and replaced them with a home made abomination of parts.

I am trying to restore it to near original and have managed to get a correct loom and switchgear for both sides of handlebars. In order to complete the wiring connections - especially to the fuse box I need a wiring diagram.

The problem is that mine has different switchgear to the early models with the RH having only the run/stop & start switches. This switch has only 3 wires in it's connector to the wiring loom. The loom is the correct one that has the 3 wire connector. Every wiring diagram I can find shows a connector with 7 or 9 wires.

Can anybody help with the correct wiring diagram?

Thanks

Steve

[davidr]

Hey Steve,
I'm not on this board posting as many other guys here. I'm mostly a lurker, but I saw your post and I feel your pain.
I'm the second owner of a U.S. model 1978 900 GTS with controls that probably match those you have acquired. At least it sounds that way. My bike has a four fuse loom, (three live fuses, one spare), Ducati Elettrotecnica ignition units, and the three pin connector for the right hand switch you referenced.
The US GTS schematic may be something close to what you are looking for. However, if you look at the wiring diagrams Steve has on this site, and/or on the Ducati Meccanica site, for the 76-77 750/900 SS models or, the Darmah SD, you may be able to find them helpful as those looms have much, if not all, in common with some GT and GTS versions. It's a puzzle sometimes working on this stuff if you're trying to make it "original".
In the process of researching the renovation of my own GTS I decided I would build a new harness by copying what was on the bike and referencing the "correct" schematic in the "US Supplement" to the owners manual. That was an easy thought to have, but in looking at what exists on the bike, which is all original, I discovered the loom doesn't exactly match what the schematic says should be there. It's pretty close, but it's also "close" to elements of the aforementioned schematics above, seeming to share bits of some if not all. That is to say, they are all Ducati specified parts and colors, but its almost as if the loom was built from bits that happened to be available on the assembly line the day the bike was built. In the case of my bike, May of 1977.
After reading the restoration source books by Falloon and Walker, other materials and my own digging, I would have to say there are multiple variations in loom build of what may be termed "correct" for a given model, year and market for which a bike is specified. At least for the GT/GTS. What exists in front of you may be unique unto itself. Part of the charm of owning Italian goodies I guess, and where the fun begins! This is where that line "patience is a virtue" may have been inspired.
Others on the forum may disagree with me here about this. I only offer these as observations from my own experience in the process of trying to bring another old bike back to life.
Anyway, I do have a US GTS schematic and I would be happy to get you a copy somehow if you think it would be helpful. I've only got the paper version from the manual supplement which I can copy and get to you via the post office, or I can see about getting it scanned and email it.
Let me know what you think.
Best.

Dave

[sdprice50]

Hi Dave

Thanks for your comments. I do tend to agree with you that Ducati did not necessarily stick to exactly what was published as "original". I think they did as you said and used what was available at the time. I guess the late 900GTS was bound to be a bit of a mix of the 860GTS and the other bikes around at the time.

The nearest wiring diagram I had was for the 860GTS which had a different arrangement of switches on the handlebars and I assumed that this would be the only bit of wiring that would not match. This was a foolish assumption and caused a great deal of confusion.

What did not help is that one of the switches I had bought as NOS had one function not working. However the good news is that I have finally managed to figure it out and everything is now working. Is it "original"? All I can say is that every part matches a bit of one of the wiring diagrams I have managed to obtain for one of the models available at the time - that is the best I can manage .

Thanks for the offer of the wiring diagram but I do not need it now.

I will post pictures as soon as the tank and side panels return from being sprayed.

Cheers

Steve

[davidr]

Steve,

Glad to hear you've already managed to get the electrics working. I hope to get my loom together with the same success.

Curious to see photos of your bike with fresh paint...maybe even a shot with the lights on!

Enjoy the ride!

Dave