750 Paso Wiring Upgrade to Improve Starting

Post by **jcslocum** » Wed Jan 26, 2005 2:15 pm

I have finally figured out how to place the upgrade instructions on the web. This is a PDF file that will open in a new window. To just download it directly, just right click the link below and use the save target command. You can download it here:

NEW VERSION!!! Click HERE -->> Upgrade Instructions Rev2 (11/25/2006)

As some of you know the Paso has very unique way of protecting from theft. If you don't know about it's electrical quirks, you can't get it started. The colder weather has only made this condition worse if that's possible. In the colder weather it just won't crank over. One solution is to use the kill switch to remove the ignition load as you get it cranking. Once the starter has the engine turning over, you flip the kill switch to the "ON" position for spark and the engine catches.

An hour spent with a voltmeter and the wiring diagram (oh such Saturday fun) revealed the following:

Battery 12V
Feed to Fuse Panel 10V
Coil Feed 9.2V (25% loss!!!)

The voltage drop from the battery to the fuse panel is caused by the route that the power takes. The full electrical load is switched by the ignition (key) switch at the head stock. Along the way it goes thru 6 plugs/connectors and drops at least 2 volts. The fuse panel is 6 inches away from the battery, so why they run the juice thru about 14 feet of wire on the round trip is a mystery only the engineers at Ducati understand. I cleaned all of the plugs, contacts and the ignition switch to the best of my ability to little positive effect. The only way to resolve this problem is to install a relay to switch the power on and off near to the fuse panel. I did this today (following directions posted here) and I now have only a 2/10th volt drop in the system: 11.8V and the fuse panel and the ignition switch now only operates the relay instead of all of the current for the bike. After the system relay install, the coils were still quite low in the voltage department, with an improvement to 10.2 (from 9.2) volts mearured at the coil.

The solution to the low voltage is an easy one! Just throw in another relay. I ran a feeder from the fuse panel to a relay at the coils and fed them that way. By using the stock coil wiring to switch the relay, the kill switch functions normally. The voltage at the coils is now 11.8V and the spark will be much STRONGER particularly when starting cold.

I was going to put in a relay for the headlights but now I'm not sure if it's necessary. I thought that the headlight being on during starting was the cause of the intermittant "No Starter" condition but it was actually the system voltage drop and the coil load that was keeping the starter solenoid from engaging. This work took about 4 hours to do and is very easily reversible and looks quite stock.

Cost: $5 for some Bosch Relays ( I had some laying around), crimp on type connectors and some wire.

fasterdammit · Post by **fasterdammit** » Wed Jan 26, 2005 3:29 pm

Jon -
That rules! Thanks for posting the walk-through and the link. Definitely a smart mod. I like that it's easily reversible and better yet, looks stock.

I fabbed my own Euro tail section after finding just the Euro tail light lens on ebay - used the same wiring harness, same connectors as the US-spec stalks - the only modifications required were two holes in each of the plastic horizontal brakelight isolator panels to mount the new blinkers, and a slightly enlarged hole in the back of the unit itself to pass the wires though. Wouldn't take 10 minutes to return it to stock.

But this I like ... once I dig the garage out of the snow, it's on my list of things to do ...

Jake

lceriani · Post by **lceriani** » Wed Jan 26, 2005 7:56 pm

I have problems printing page 3 with Acrobat Reader 6 (err 14: missing object)... am I the only one?
Jon, would you please check if everything is ok?
Thanks...

LC

silverfox · Post by **silverfox** » Wed Jan 26, 2005 10:45 pm

Downloads fine for me.
Hey, thanks heaps - it looks like a worth while exercise - I once had heaps of trouble with my battery sensing wire going from the instrument panel that always had heaps of voltage drop and overcharged my batt to hell so I'm not surprised that there are other drops in the system.
One question though - what does 12 and 14 gauge wire translate to in mm for the rest of the world who want to be different?

PS: thanks for the 748 comparison but I'm now very depressed.

Cheers
Tony

Post by **Skins** » Thu Jan 27, 2005 6:05 pm

Iceriani, when I got Jon's wiring instructions, he sent them to me via email. If you need more information, maybe you could ask him to do that for you. Or I could send my copy to you by email, if you like.

Post by **jcslocum** » Fri Jan 28, 2005 3:23 pm

lceriani wrote:I have problems printing page 3 with Acrobat Reader 6 (err 14: missing object)... am I the only one?
Jon, would you please check if everything is ok?
Thanks...

LC

I will resave the file again and replace it on the site. Don't know what the problem could be otherwise.

lceriani · Post by **lceriani** » Mon Jan 31, 2005 10:14 am

Problem solved!

I had errors opening the file with Adobe Acrobat Reader version 5.0.1 , now I upgraded to version 6.0.1 and... no more errors!
Thanks, it is a great job.

LC

Paul · Post by **Paul** » Mon Feb 07, 2005 11:21 am

Jon,

I also experienced the same error 14 when I downloaded the file and opened it. I was using Acrobat Reader 5.01. I upgraded to 7.0 and it works fine.

Great job with the documentation.

Paul

Post by **jcslocum** » Tue Feb 08, 2005 1:51 am

I resaved it in Acrobat 5.0. Maybe it will be better? Who knows.

frankblack · Post by **frankblack** » Sat Feb 12, 2005 1:44 pm

Very nice instructions. Can't wait to do this.

One question -- does anyone make aftermarket coils that will fit the Paso without major mods. If so, what should the resistance rating be?

I'm hoping to hear someone say "Dyna" as they have worked wonders on my 500cc Guzzi.

Again, John -- nice job.

Finnpaso · Post by **Finnpaso** » Tue Feb 15, 2005 7:56 am

Hi!

I have installed 4 extra relays to my 750 Paso electrics and now she function, like should:

1. for low beam
2. for high beam
3. for power supply "main relay"
4. for coils

Happy with it now

))

Antti

Post by **paso750** » Tue Feb 15, 2005 10:43 am

4 relays are a little bit much as one or two should be sufficient.

There`re lots of stronger coils beginning from Accel, Andrews, DynaCoils, Silent Hektik etc. Beware that they don`t have less than 3 ohms resistance. The Silent-Hektik coils which are amongst the strongest do have a bit less and are therefore recommended with the Silent-Hektik ignition only (I´ve driven these with the original CDI units and nothing happened, but you never know).
Before you change to stronger coils check if you have full voltage at the coils. If not correct this as this might already be the solution. If you really go for aftermarket coils try get get good low-res plug cables also. Some of the aftermarket silicone cables are crap, but there are also a few good one. The ones from Silent-Hektik are one of these.

Here some technical info about the coils (the page is german, but anyway ...)

http://www.silent-hektik.com/page80.html

Gerhard

Post by **jcslocum** » Sat Feb 26, 2005 9:37 pm

I have had a few questions about the "extra/left over" orange wire. Here a short eplanation:

I get plenty of questions about the orange wiring!! Have you looked at the wiring diagram that is on a web site??

http://www.geocities.com/750paso/

As I read the drawing, the orange wire begins at the kill switch #16 and travels a long route thru a few plugs to the coils; 28 & 25. This is the orange wire that you use to switch the relay on and off. The "Y" wire harness ( that you make) just jump from the relay to the coil terminals. The other plug from the coil that has a wire in it runs up to the ignitor boxes; 27 & 24. That just gets taped off to the frame. Part 2 step 1 of the instructions.

Sorry for any confusion!

dead · Post by **dead** » Sat Mar 12, 2005 10:01 pm

So I downloaded acrobat 7 and im still unable to view the file, i keep getting a corrupted file msg. I would love to take a look at your relay wiring guide. If all else fails can you email it to me @ rtraschler@yahoo.com?

Thanks
Richard

Post by **jcslocum** » Sat Mar 12, 2005 10:26 pm

I sent it to you.

Good luck!