Replacing Rally 200 wiring loom
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'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 543
Location: Melbourne
Fri Jun 22, 2018 1:43 am quote
After ten years with my Rally I know every inch of it, and having rebuilt the engine and suspension, the wiring is now the worst part of it. I've had a couple of electrical issues over the years, and managed to fix them, but I know where all the bodies are buried. It's only a matter of time before this 42 year old wiring strands me, and I'd rather get ahead of it. I think it's time for a new wiring loom.

SIP has a variety of looms for sale, and I've confirmed with them that this one is the best fit for my Rally. Mine is in original configuration, with Femsa ignition and US indicators. I'll have to modify this loom slightly to add leads for the rear indicators, but otherwise in theory it should be plug and play.

https://www.sip-scootershop.com/en/touch/Details.aspx?ProductNumber=87001410#Recommendations

Just wondering if anyone else has experience using these looms or other ones. I'd like to do this replacement over the Aussie winter.

Last edited by autojack on Sun Nov 04, 2018 7:37 pm; edited 1 time in total
Member
79 P200E ; 61 VBB
Joined: 22 May 2016
Posts: 11
Location: Ogden, UT
Fri Jun 22, 2018 8:01 am quote
I replaced mine in my double yellow p with the SIP worked great only difference was the color of one wire on the turn signal circuit and an extra ground terminal near the battery. Everything works great.
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 6951
Location: Victoria, Australia
Fri Jun 22, 2018 3:36 pm quote
I hope it comes with a diagram as I see there's not one on the page. Also I hope it's absolutely perfect in every way as I've just ordered a SIP loom for the smallframe.
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'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 543
Location: Melbourne
Fri Jun 22, 2018 3:46 pm quote
It hadn't occurred to me that they would use different colors from the stock harness, so I thought the wiring diagram from Scooterhelp would be sufficient.
Hooked
vespa 125 vnb1t
Joined: 13 Jul 2011
Posts: 365
Location: antibes , france
Sat Jun 23, 2018 2:14 am quote
iv'e done two 12v loom conversions on primavera's one with indicators both sip looms didnt have wires for the front side/parking light
each came with a diagram but in german
Ossessionato
1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
Posts: 4763
Location: So Cal
Sat Jun 23, 2018 4:58 am quote
I got a SIP loom for one of my 70’s Soops. Ended up not needing it, and gave it away, but it was good quality and all the connections were there. The wire color differences are not a big deal ... once you lay it out it’ll be clear where everything goes. If not just get out the multimeter...
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'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 543
Location: Melbourne
Mon Sep 03, 2018 10:55 pm quote
Picked up the new loom today. The diagram in German is serviceable, although it looks like it is a fifth-generation photocopy... oh now I've just realized, I think this must be from a factory repair manual. Anyway I translated the colors into English and matched everything up, it looks good. I forgot that, in addition to the indicators, there is one other slight difference - Euro Rallys had the high/low beam, horn, and kill switch all on one switch. US ones had the indicators and kill switch on one, horn and high-low beam on the other. It looks like this loom is wired for a separate indicator switch, so I will just need to route the kill switch lead over to that branch. Shouldn't be too horrible. I hope...

I also just realized that this loom doesn't seem to have leads for the front brake light switch. I'll have to look into that.
Molto Verboso
Joined: 26 Oct 2015
Posts: 1571

Tue Sep 04, 2018 6:14 am quote
autojack wrote:
Picked up the new loom today. The diagram in German is serviceable, although it looks like it is a fifth-generation photocopy... oh now I've just realized, I think this must be from a factory repair manual. Anyway I translated the colors into English and matched everything up, it looks good. I forgot that, in addition to the indicators, there is one other slight difference - Euro Rallys had the high/low beam, horn, and kill switch all on one switch. US ones had the indicators and kill switch on one, horn and high-low beam on the other. It looks like this loom is wired for a separate indicator switch, so I will just need to route the kill switch lead over to that branch. Shouldn't be too horrible. I hope...

I also just realized that this loom doesn't seem to have leads for the front brake light switch. I'll have to look into that.
well, you can always Tee a pair of wires down to your rear brake light switch so that you can activate the brakes lights via the front brake lever.

And since you have had the harness in your hands, does it feel like SIP uses quality wires and terminal ends?
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'76 Vespa Rally 200
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Posts: 543
Location: Melbourne
Tue Sep 04, 2018 4:08 pm quote
whodatschrome wrote:
well, you can always Tee a pair of wires down to your rear brake light switch so that you can activate the brakes lights via the front brake lever.

And since you have had the harness in your hands, does it feel like SIP uses quality wires and terminal ends?
Yeah, I am expecting to have to feed some additional wires around, so I just need to tally them up.

I'm happy with the quality of materials used. I know from experience that this wiring diagram is accurate for the US bike, and I can see that the new loom uses some different colors for the switches and indicators. Probably correct for the Euro bike. So I will just need to use the multimeter to trace things out. I'll document this for future generations.

I am a little disappointed about the quality of the connector crimping. Almost all of them look like this. The rear tabs should enclose and grip the insulation, for strain relief. I'm going to have to fix these up myself.

IMG_20180905_095015.jpg

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'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 543
Location: Melbourne
Sun Nov 04, 2018 7:41 pm quote
I'm trying to figure out how I will modify the new wiring loom to run the rear indicators on my bike. I know the current setup, as on the P series bikes, powers them through the pins on the cowls. But where/how are the electrical connections made inside the openings in the chassis that the pins go into? Can anyone show me a picture of this, or describe it? I wonder if those wires even run through the main loom, or if they were wired separately because they only went on the US bikes. Then again that wasn't the case from the P series onward, so you'd think those would have integrated these leads into the loom.
Molto Verboso
08 GTS 250, 79 P200E, 62 Allstate
Joined: 11 Jan 2006
Posts: 1178
Location: Florence, OR
Sun Nov 04, 2018 8:20 pm quote
autojack wrote:
I'm trying to figure out how I will modify the new wiring loom to run the rear indicators on my bike. I know the current setup, as on the P series bikes, powers them through the pins on the cowls. But where/how are the electrical connections made inside the openings in the chassis that the pins go into? Can anyone show me a picture of this, or describe it? I wonder if those wires even run through the main loom, or if they were wired separately because they only went on the US bikes. Then again that wasn't the case from the P series onward, so you'd think those would have integrated these leads into the loom.
Hey Auto - I don't know if this is going to answer your question or not, but hopefully this will help you figure it out. I've got a 79 P200 US version. The cowl pins are the hot wire to the blinkers. Brown for left, and Blue for right. The cowl catch is the ground (Black wire). All three of these wires go into the wire loom and connect at the block under the horncast. I'm going to post a pic of the inside under the tank, and a wiring diagram. I hope this helps!

20181028_152154_resized.jpg
The Brown wire (Left blinker) goes to the cowl pin and the black wire at the end of the spring is grounded through the loom at the connector block under the horncast.

wiringdiagrammv_385.jpg
Wiring Diagram...

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'76 Vespa Rally 200
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Sun Nov 04, 2018 8:24 pm quote
qascooter wrote:
Hey Auto - I don't know if this is going to answer your question or not, but hopefully this will help you figure it out. I've got a 79 P200 US version. The cowl pins are the hot wire to the blinkers. Brown for left, and Blue for right. The cowl catch is the ground (Black wire). All three of these wires go into the wire loom and connect at the block under the horncast. I'm going to post a pic of the inside under the tank, and a wiring diagram. I hope this helps!
That is *perfect!* So I would be able to get at this from under the tank - I've had mine out once in ten years, to put in a new rear shock. I didn't look too closely back then at what else is under there. OK so I will need to feed two more wires down to that point in my harness. Hopefully I can manage that! Thanks a lot
Molto Verboso
08 GTS 250, 79 P200E, 62 Allstate
Joined: 11 Jan 2006
Posts: 1178
Location: Florence, OR
Sun Nov 04, 2018 8:32 pm quote
autojack wrote:
That is *perfect!* So I would be able to get at this from under the tank - I've had mine out once in ten years, to put in a new rear shock. I didn't look too closely back then at what else is under there. OK so I will need to feed two more wires down to that point in my harness. Hopefully I can manage that! Thanks a lot
Yup - under the tank. This picture was taken just a few days ago. I put in a CHT and ran the wire up to the horncast. I ran an extra green wire and a couple of spare "stringers" from weed whacker string for future use or just in case.

You can just see a bit of the brown wire, and the black wire on the end of the spring. They both feed into the loom and up to the junction block under the horncast.

Oh, and while you have the tank out you might as well replace the fuel line.

And I'm glad I could help! Keep us posted when you get it all sorted!
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'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 543
Location: Melbourne
Sun Nov 04, 2018 8:53 pm quote
qascooter wrote:
Yup - under the tank. This picture was taken just a few days ago. I put in a CHT and ran the wire up to the horncast. I ran an extra green wire and a couple of spare "stringers" from weed whacker string for future use or just in case.

You can just see a bit of the brown wire, and the black wire on the end of the spring. They both feed into the loom and up to the junction block under the horncast.

Oh, and while you have the tank out you might as well replace the fuel line.

And I'm glad I could help! Keep us posted when you get it all sorted!
Good point on the fuel line, I even have a spare length ready to go from a previous effort that I ended up aborting.

I'm surprised that they bother to run a ground wire from the spring through the chassis. I would have thought they would just ground to the chassis itself right there somewhere.

How did you fish the new leads through the frame without removing the old harness? I'm intending to tie pull strings or wire of some kind or other to the old harness and feed them through as I remove it, and then use those to help pull the new one into place.
Molto Verboso
08 GTS 250, 79 P200E, 62 Allstate
Joined: 11 Jan 2006
Posts: 1178
Location: Florence, OR
Sun Nov 04, 2018 9:58 pm quote
autojack wrote:
How did you fish the new leads through the frame without removing the old harness? I'm intending to tie pull strings or wire of some kind or other to the old harness and feed them through as I remove it, and then use those to help pull the new one into place.
Check out this thread: P200e - this time for real! (Page 6)
Basically I ran an electricians fish tape from the horncast area to the tank area, then gently pulled it back through with the bundle of wires taped to it. It wanted to hang up around the rear brake area - it got kinda tight, but I just pulled a bit harder and it popped through. I've got pics in the thread above.

What you're going to do sounds like it'll do the trick and you won't need to use an electricians fish tape.
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'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 543
Location: Melbourne
Sun Nov 04, 2018 10:17 pm quote
qascooter wrote:
Check out this thread: P200e - this time for real! (Page 6)
Basically I ran an electricians fish tape from the horncast area to the tank area, then gently pulled it back through with the bundle of wires taped to it. It wanted to hang up around the rear brake area - it got kinda tight, but I just pulled a bit harder and it popped through. I've got pics in the thread above.

What you're going to do sounds like it'll do the trick and you won't need to use an electricians fish tape.
Thanks a lot! Just gives me an idea of what to expect when I get my stuff apart. Much appreciated!
Member
PX200E
Joined: 09 Nov 2018
Posts: 8
Location: Melbourne
Fri Nov 09, 2018 11:13 pm quote
Done it did not enjoy it
Years ago replaced a Rally 200 loom and still have the scars. This was pre SIP days and used a Beedspeed one. The biggest challenge was there is a welded plate in about halfway to the rear brake that has two holes cut through for cables and loom. My loom kept getting caught on that point and had to stick my hand deep inside the body to get a draw wire through.

That hole is pretty tight and ended up having to remove the side cover clips and springs even then I could only just get my hand in.

Out of interest why keep the indicators? Pre 76 should just squeak into the "none required"ADR rules same with the front brake.

Do you have a neutral light? Recall a Victorian Rally that had one back in the day that had been a private import.
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'76 Vespa Rally 200
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Posts: 543
Location: Melbourne
Sat Nov 10, 2018 1:31 am quote
Re: Done it did not enjoy it
Back2Scooters wrote:
Years ago replaced a Rally 200 loom and still have the scars. This was pre SIP days and used a Beedspeed one. The biggest challenge was there is a welded plate in about halfway to the rear brake that has two holes cut through for cables and loom. My loom kept getting caught on that point and had to stick my hand deep inside the body to get a draw wire through.

That hole is pretty tight and ended up having to remove the side cover clips and springs even then I could only just get my hand in.

Out of interest why keep the indicators? Pre 76 should just squeak into the "none required"ADR rules same with the front brake.

Do you have a neutral light? Recall a Victorian Rally that had one back in the day that had been a private import.
I have small hands that can get into tight spaces, I've done work at the back of my Porsche engine that everyone else says you need to drop it to accomplish. I also have a flexible inspection camera, and I'm planning to pull a gear cable through when I remove the old one, to use as a guide/pull wire. With all that, I think I'll manage, but yeah not looking forward to it. I didn't think the blockage had holes in it, I thought it was two fences, one welded to the top and one to the bottom of the tunnel, so you had to go over one and under the other. Maybe that's a different model.

I like the fact that my bike is bone stock except for the pipe, and the indicators work fine, so why not keep them? It doesn't have a neutral light, I've never seen that on a Rally.
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PX200E
Joined: 09 Nov 2018
Posts: 8
Location: Melbourne
Sat Nov 10, 2018 5:21 am quote
A camera and small hands will make the job a bunch easier; wish I had them as it would have saved hours of garage time!

Might be wrong but the US Cali Rallys required a neutral indicator by law. My Rally had had bar end indicators but they had got "lost" between delivery and being acquired in the late 80's. Was registered with none as a pre compliance version.

Someone imported at least 1 Rally from the US. It used to turn up at national meets in the early 90's and had the US indicators and sensor on the gear selector box.
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'76 Vespa Rally 200
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Posts: 543
Location: Melbourne
Sun Jan 06, 2019 4:02 am quote
OK, I need some help from the brain trust. I spent some time earlier today mapping out what is different from the Euro wiring loom that I got from SIP, and my stock US wiring. I had thought it was just the indicators and kill switch, but now I'm going down a rabbit hole having discovered that the wiring from stator to regulator to the rest of the bike is also different, and I can't quite wrap my head around why. I would really like to understand this so I can figure out how the new loom is going to hook up (with or without further mods).

Attached is a scan of the wiring diagram I received with the loom (if anyone can share a clearer copy of this, I would appreciate it - looks like it is from a service manual or something), and the diagram from scooterhelp.com which matches what is in my bike. I will refer to these as the US vs. Euro wiring.

The US wiring has two yellow leads running from one coil of the stator, through the junction box on the engine, and into the regulator/rectifier. The Euro wiring has only one yellow lead. Question: why two leads vs. one? I think I will need to add one to work with my rectifier.

The US wiring has a pink lead coming from the rectifier, through a fuse to the battery, and also jumpered at the fuse into a red lead which goes to the key switch. The Euro wiring just has a red lead which goes straight to the battery (and testing my harness indicates it does not go anywhere else). Question: I must be missing something, but how is power getting from the battery into the rest of the circuit in the Euro wiring?

This is where I am really baffled. The US wiring has a purple lead coming from the rectifier to the indicator flasher, which is jumpered to a green-and-white lead which goes to the keyswitch and then to the horn. From the horn it appears to jumper to a green and black lead which then goes to the hand and foot brake light switches. The Euro wiring has a purple lead which goes from the rectifier directly to the key switch. The Euro indicator flasher seems to get power via a yellow lead from the foot brake switch. So in the Euro system, it seems that one output from the regulator JUST charges the battery, and the other goes to the key switch and then to everything else. But how does the battery power anything? Is there also a jumper at the regulator so that battery voltage can flow through it to the other output?

If your head is swimming after trying to read this, look at the diagrams. If it's still swimming, you will see where I'm at. I'm not sure how I am going to wire my stator, regulator, and indicators with the current harness. It seems like the difference in regulator design may impact a few things. If anyone has insight about that, it might be useful!

euro rally wiring loom.pdf
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 Filename:  euro rally wiring loom.pdf
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VSE1.wKey.Batt.Blinks.B1977.pdf
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 Filename:  VSE1.wKey.Batt.Blinks.B1977.pdf
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Ossessionato
1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
Posts: 4763
Location: So Cal
Sun Jan 06, 2019 9:28 am quote
Electrical stuff can make you crazy. Before getting too wrapped up in wiring diagrams and wire colors, the first thing you need to do is figure out your “end game”.

Are you trying to re-create the stock US electrical wiring on your Rally? Or are you doing the Euro wiring? Or some variation?

If you’re just trying to add flashers to your US bike, take both harnesses out and lay them side by side. Forget about colors for now... figure out what connections are missing from the new harness and just add them.

To answer your questions:

1. Why two yellow leads vs. one? US battery bikes used a “double yellow” off the stator for rectification. Euro’s are rectified differently. You’ll need to run a second yellow wire from the terminal to the US rectifier.

2. How is power getting from the battery into the rest of the circuit in the Euro wiring? Through the key switch.

3. Is there also a jumper at the regulator so that battery voltage can flow through it to the other output? Basically yes. That’s a diode AC/DC converter. It’s the Euro equivalent to the US rectifier.

Hope this helps.
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 6951
Location: Victoria, Australia
Sun Jan 06, 2019 11:01 pm quote
I guess another option is to re-create the original loom? More work but less brain pressure!
With the old loom pinned down on a board and unwrapped, it ought to be pretty easy to copy. Just need a decent stripper and crimper, and of course some good quality connections and wire of the right colours.
I looked for some wire last year and finally found some that is sold with a trace colour - though I see there is only a few in your diagram that needs a trace. Anyway this seller has lots on ebay of varying thicknesses -
https://www.ebay.com.au/itm/Selection-of-6-x-5-m-3mm-AUTO-WIRE-20-Amp-TYCAB-AS-PER-LISTING-F-POST/152733133813?hash=item238f9aabf5:g:Z14AAOSwuMFUalz5:rk:14:pf:0
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'76 Vespa Rally 200
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Mon Jan 07, 2019 12:11 am quote
Thanks SocalGuy, that helps! I'll definitely add a yellow lead for the regulator, and knowing that current can flow back through the regulator from the battery to the key switch in the Euro setup helps clarify things. It's interesting that the Euro setup does not seem to have a battery fuse.

Ginch, I definitely think laying them out will help, but I think I can make do with what I have for some things. It may not be practical to try to replicate the US harness exactly.
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'76 Vespa Rally 200
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Posts: 543
Location: Melbourne
Mon Apr 29, 2019 5:31 pm quote
These wiring harnesses are doing my head in. If I had known how different the Euro harness was from the US, I would have just copied my US harness from scratch. There seem to be some fundamental differences, and I am hesitant to try and use the new/Euro harness without making it match the old/US one.

Part of the problem is possible that I keep trying to understand what the hell is going on in the old harness. What is this purple lead running from the rectifier to the indicator flasher, where it is jumpered to a white and green wire that runs to the horn?? Rectifier, indicator, horn?? WTF? And why does the green and black lead for the brake light switches also run through the horn? Whyyyy???

Whereas the leads for the brake switch in the Euro wiring harness are white, yellow, blue. It's not even clear how I would wire that into my switch. Raaaaa.
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 6951
Location: Victoria, Australia
Mon Apr 29, 2019 6:47 pm quote
I feel your pain. It's questions like that that made me do my own loom and go all DC.

I think that often these connections are jumpered for convenience... I mean to avoid a dedicated wire to the horn etc. That's how I see it anyway.
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'76 Vespa Rally 200
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Mon Apr 29, 2019 7:44 pm quote
It's like every time they changed something, they just took the loom from the previous model and added a wire here or there.
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 6951
Location: Victoria, Australia
Tue Apr 30, 2019 12:33 am quote
autojack wrote:
It's like every time they changed something, they just took the loom from the previous model and added a wire here or there.
Didn't you know? In English Piaggio translates as "random"...

Maybe before doing anything to the new loom, you could sell it as new and make your own using the original as a template. Craig just told me about an automotive electrical supplies business in Bayswater that he's used previously.... here it is - https://jaydeeautocables.com.au/
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'76 Vespa Rally 200
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Posts: 543
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Tue Apr 30, 2019 3:36 am quote
It seems unlikely anyone would happen to need a Euro Rally harness. I had thought about trying to return it to SIP, even if only for credit, but it seems unlikely they would take it. I bought it ages ago.

Thanks for the tip on Jay Dee, that might come in handy.
Ossessionato
1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
Posts: 4763
Location: So Cal
Tue Apr 30, 2019 5:01 am quote
Get 25ft of this and some connectors and make your own.

https://www.wirebarn.com/16-GAUGE-6-CONDUCTOR-TRAILER-CABLE_p_635.html
Ossessionato
73 Rally, 74 Rally, 76 ET3, 80 P200, 63 Li125, 65 Li225 Silver Special, 86 Elite 80, 2015 HD Road Glide Special, 2011 Ural Tourist
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Location: Oceanside/ SF
Tue Apr 30, 2019 6:49 am quote
Auto-

Forgot your name but you hooked me up with your 6V tender before you left. Give me a bit to read up but hope I can help.

I’d second what others have said and just use that SIP harness as best as you can and then wire in the rest. Time wise, buying a correct one is the fastest, then Frankensteining one, then building your own from scratch.

So from reading up, youre having problems with the regulator wiring, turn signals, no fuse at the battery and no front brake switch?

Regulator- does your original regulator/rectifier work or did you replace it with something different? I’m thinking you can run another yellow wire from the stator to your regulator (if its OG) otherwise, you can ground one yellow stator wire and get 12V AC out of the other yellow wire.

Turn Signals- Did the 77’s have the 2 post or 3 post turn signal relays? Hopefully two like the euro diagram so you can just make jumpers for the rear end.

The aluminum stalks that hold up the pods on US Rally’s can cause grounding problems. I’d recommend running a dedicated ground wire through the stalk to the pod. I did that with Modkuo’s 100 sport donor frame build a few years ago and the lights work every time, full brightness. You’ll have to disassemble the headset so you can unscrew the stalks from the headset but since the headset will be coming off for a harness swap, now will be the time to run the grounds and not just rely on the mounting bolts to do the grounding.

Inline fuses are easy to find and you’ll just need to solder one in. Make sure you dry fit it before soldering as the battery box has a few bends and curves you’ll need to account for when mounting.

The front brake switch I’d say run two wires from the front switch to the rear switch like the US diagram shows.

Let me know if you have any other questions. PM works
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'76 Vespa Rally 200
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Sun Jun 02, 2019 6:35 pm quote
This project has turned out to be a big pain in the ass, but I am making some headway now. For those who come after me, take my advice: it's easier to build a loom from scratch than to modify a Euro one to match a US bike, unless you are willing to end up with a harness that doesn't match any published wiring diagram. My ADD won't allow that, so part of the work involved in my case is changing out some colors of wire that are different between Euro and US. But there are other things that just wire up very differently, and the Euro harness is not going to work for these. Differences I can remember off the top of my head:

* US rectifier takes two inputs from the stator, and has two outputs; Euro has one input and two outputs.
* US indicators and horn share a DC path; Euro indicators and brake switch share a DC path.
* US has a hand brake switch wired in parallel with the foot brake switch.
* US has rear indicators.
* US regulator and battery can both independently power all DC loads in the bike (I believe this is to comply with US law that taillight must illuminate even when the engine is not running), and thus are wired somewhat differently to Euro.

By comparing the old and new harnesses and their diagrams side by side, I was able to work out what changes I would need to make. Then I eventually found places where I could buy the ten colors of wire I needed mostly in small lengths to keep cost down. I then struggled for awhile actually getting started making changes to the new harness, before I realized it would be much simpler if I labeled every branch, so I could see at a glance the path each wire needed to take. I used masking tape for this, so I can remove it later.

Most recently I have been struggling to actually feed new wires through the loom. Pushing them through just does not work, the wires are not stiff enough to overcome the friction over the lengths required. Taping a gear cable to a wire and pulling it through didn't work, the two just separated. I was going to try to use a strand of steel wire and secure it more strongly to the end of the wire I want to pull. But then Ginch and his friend James stopped by yesterday to check on my progress, and James pointed out that at this point it would be easier for me to just pull all the sheathing off the new harness, lay out my new wires, and then slide the sheathing over everything (perhaps using a pull string around each bundle, and some grease to help things along). I'm going to try that later, I hope it will help.

I took lots of pictures of the hookups inside the headset and at the horn, but now that it's been a few weeks since I took everything apart, I am still a bit worried that I am going to have a hard time getting everything hooked back up correctly. But hopefully that will not be the case. I have to remind myself, it's just wires going from A to B, and I've built radio kits that have hundreds or even a thousand or more parts. I'll get this done.

For you Aussies, I bought some wire from https://jaydeeautocables.com.au and some from http://www.rapidcables.com.au. I also bought a kit of spade connectors on eBay because I only had one of the three sizes required on hand. I spent some time browsing https://www.ozautoelectrics.com as well, they have tons of stuff, but in the end prices on what I needed were better at the other sites.

Hope to have a final update soon!
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'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 543
Location: Melbourne
Mon Jul 01, 2019 4:54 am quote
OK, I'm nearly done but I need some advice from the brain trust. I've got the new loom fed from the tank up and out the horn cast. Then I'm going to feed some old cable housings down from the top of the fork tube, and use those to pull the wires up the rest of the way. There are three bundles to pull up: the hand brake switch (2 wires), the indicators (3) and the rest (8-10).

Here's the question: does it matter whether I route these to one side or the other of the cable housings that are already in there? I have "before" pictures so I can see how they routed before, but so far I think it's going to be impossible to exactly duplicate that. When I go to pull them through, the wires just kind of take the easiest path. I'm thinking it should be ok as long as I get the general position right, so nothing is binding when I put the headset on. Thoughts?
Hooked
'63 VBB2T - '18 300 GTS Super Notte
Joined: 26 Apr 2019
Posts: 149
Location: Belgium
Mon Jul 01, 2019 7:30 am quote
autojack wrote:
I have "before" pictures so I can see how they routed before
Hi, I'm trying to do the same on my VBB.
Would you mind posting the before pics please?

Thanks!
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'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 543
Location: Melbourne
Tue Jul 02, 2019 9:29 pm quote
autojack wrote:
Here's the question: does it matter whether I route these to one side or the other of the cable housings that are already in there?
I'll answer my own question: it matters If you look at the underside of the headset, where the wires and cables come up, you can see clearly that there are openings for cables and openings for wires, and you really need everything to be positioned right - they can't cross over each other after they come out of the chassis.

The throttle cable and two wiring bundles need to feed behind the steering column lock, and the wiring bundles need to be behind the throttle cable. I had them reversed, so I had to pull the throttle cable out and then feed it up again after I got the wires in.

I need to do the same on the other side now, swapping the clutch and two gear cables with one wiring bundle. But I think this will be a little easier to do, because I won't have the steering lock in the way. But I'm nearly done with all this routing!
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'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 543
Location: Melbourne
Tue Jul 02, 2019 9:32 pm quote
DD_VES wrote:
autojack wrote:
I have "before" pictures so I can see how they routed before
Hi, I'm trying to do the same on my VBB.
Would you mind posting the before pics please?

Thanks!
I would guess that your VBB setup in different from my Rally, but here is my before picture. The wiring bundle on the left is for the indicators. On the right there are two bundles, one for the hand brake light switch, and the other is "everything else." You can see that all wires need to be close to the center of the tube, behind the control cables.

IMG_20190416_141119.jpg

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'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 543
Location: Melbourne
Sun Jul 28, 2019 4:37 am quote
All right, it's time for the thrilling conclusion to Replacing A Vespa Wiring Loom - How Hard Could This Be? I'm your host, autojack!

I was hoping to get this job done within a month. Instead it ended up taking me about five. Most of that time was spent screwing around trying to make the Euro harness work with a minimum of modification, before I finally bit the bullet, pulled it apart, and basically built a new harness from scratch. Multiple online orders were placed; multiple mistakes were made and had to be undone; and multiple swears were sworn. But in the end, once the new wiring went into the bike, all the electrics worked perfectly. Here are my tips for anyone that comes after me:

1. If you have a US-delivered bike from the 70s (Rally, Sprint, Super, etc.) be wary of the SIP harnesses. I knew that the European Vespas of that era didn't have indicators, but I thought that was the only difference. SIP sells a Rally harness wired for bar-end indicators, so I thought (and they confirmed via email) that I would just need to add leads for the rear indicators to make mine work. In fact, the US wiring is quite different, and if you have a completely stock system like I do, with everything working, the SIP harness is far from a drop-in replacement. I ended up pulling half the wire sheathing off and replacing a lot of wires to get the right colors going to the right places. And I had to remove the existing harness so I could compare it with the wiring diagrams from Scooterhelp and figure out the physical routing of things.
2. It's not that hard to just make a wiring loom. Knowing what I know now, I would have started by removing the old harness, tallying up the wire colors I needed, and then bought wire, sheathing, harness tape, and connectors and made up a harness. Because that's what I ended up doing anyway, and I would have saved a lot of time and frustration trying to make the SIP loom work. Incidentally, because of minimum order requirements, I have enough crap left over to make another harness or two. If anyone else is doing this, I'd be happy to sell some of it.
3. Be prepared to pull everything apart. I thought I was just going to have to remove the tank, but oh no no no. You really can't do this job without also dropping the fork and removing the headset. And then once you have the headset off, it is way easier to route the wires up the legshield tube if you pull the cables out. And when you have the tank and all the wiring out of the way, pulling out the cables is five minutes of work. I didn't drop the fork completely, but I probably should have. I lowered it about 8" - watch out though, it unbalances the bike completely. The damn thing almost fell off my lift. I wedged the spare tire under the engine to keep it stable.
4. Routing matters. For the wires and the cables. If you don't do it right, everything will bind in the headset and it won't turn. Take pictures before you remove anything, and put it back the way you found it. I fed the wires up the legshield tube and they ended up in front of the cables at the top of the tube. They were not going to feed into the headset properly that way. So I had to feed all the wires back down, pull all the cables back down, then feed the wires up, and then the cables. Note as well that the cables and wires on the right side of the tube route BEHIND the steering column lock. That is an extra bonus pain in the ass, but again, it matters.

For all the new wires I put in (which was basically everything leading to the headset and about half the other stuff) I crimped connectors on after feeding them through, after putting the headset on, etc. Ginch loaned me a big piece of hard plastic strapping to help push the wiring through the tunnel up to the horn cast. It worked pretty well, but something a little more flexible would have worked better. I was replacing my gear cables at the same time, so I used one of the old outers/housings to help pull the wires up through the legshield. Could have used that for the tunnel as well.

The Scooterhelp wiring diagram, at least for the US Rally, is amazingly accurate. I have referred to it a few times over the years but often found it confusing. But now that I've pulled apart all the wiring, I've realized that it's not the diagram that's confusing, it's the actual wiring! When you compare the diagram to the real thing, it makes more sense, and that helped me a lot with putting together my replacement. I still can't understand why the hell Piaggio did some things the way they did.

So with the wiring all hooked up, I turned the key and got working lights! The DC stuff, at least. It took me another couple of days to get all the cables reconnected and tensioned, and then I kicked the engine over and confirmed that the headlight worked and the battery was charging. Yee ha! I took it for a 20 minute ride today and it ran great, no issues. So at this point I'm calling this project done and successful. There's certainly a chance that one of my crimp connections will fail, though I have done enough of those to know how to do it right.

This Rally was my first, and still only, Vespa. I bought it ten years ago, and I've now done a full engine rebuild, front and rear suspension refresh, rewired the stator, and replaced the whole wiring loom. About the only "big" thing I could do now is paint it, but the "original paint" mafia has threatened me enough times that I think I'd better not!
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GL, PK, PE200
Joined: 24 Apr 2012
Posts: 641
Location: Deep in the heart of Texas
Sun Jul 28, 2019 9:36 am quote
Great write up Jack! Glad you got it sorted out.
Ossessionato
73 Rally, 74 Rally, 76 ET3, 80 P200, 63 Li125, 65 Li225 Silver Special, 86 Elite 80, 2015 HD Road Glide Special, 2011 Ural Tourist
Joined: 18 Jan 2012
Posts: 3216
Location: Oceanside/ SF
Sun Jul 28, 2019 9:47 am quote
Has anyone ever tried emailing SIP telling them their harness is wrong? I dont know if they’d take offense being told they are selling the wrong thing, but maybe you could help them help us?

Cool man. Glad its all over for you!
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 6951
Location: Victoria, Australia
Sun Jul 28, 2019 2:25 pm quote
Five months, that's a Personal Best, right?

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'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 543
Location: Melbourne
Sun Jul 28, 2019 6:12 pm quote
MJRally wrote:
Has anyone ever tried emailing SIP telling them their harness is wrong? I dont know if they’d take offense being told they are selling the wrong thing, but maybe you could help them help us?
I will let them know. It's not wrong, per se, it's just incompatible with US bikes. I think it should say that explicitly in their catalog.
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