guzziriders.org - moto guzzi forum Homepage
Forum Home Forum Home > Technical > General Electrical issues
  New Posts New Posts RSS Feed - Anyone ever rebuilt a wiring harness?
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Anyone ever rebuilt a wiring harness?

 Post Reply Post Reply Page  123 4>
Author
Message
Ian T View Drop Down
Falcone
Falcone


Joined: 24 Oct 2019
Location: East Yorkshire
Status: Offline
Points: 49
Post Options Post Options   Thanks (0) Thanks(0)   Quote Ian T Quote  Post ReplyReply Direct Link To This Post Topic: Anyone ever rebuilt a wiring harness?
    Posted: 02 Nov 2019 at 13:19
Hi everyone 

Well I have built a few bikes, restored a few, crashed a few and buggered up a few in my time, but I have always steered well away from the electrical bits as I just can't me my head around all the black magic and evils. 

So I have decided to rid myself of these demons and totally build all the harnesses new. I think a peg board approach so I can copy and match will be best. Can't be that hard, can it :evil: 

I've just been reading about this thin wall stuff and there is my first hurdle. 

So two questions if I may please before I start:

1. Does anyone know please what amperage thin wall cable matches the wiring in the standard loom?

2. Has anyone tried this before and are there any handy hints and tips?

The harness is off a V50 ii (1980), and I will be using the Vehicle Wiring Products catalogue and products, unless of course the general recommendations are for some other supplier. 

Cheers

Ian
Back to Top
Mike H View Drop Down
Senior Member
Senior Member
Avatar

Joined: 21 May 2014
Location: East Anglia
Status: Offline
Points: 6930
Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov 2019 at 13:44
Quote Anyone ever rebuilt a wiring harness?

Yes I have. Yes most wire and connectors were mail ordered from Vehicle Wiring Products (VWP). Also you will need an appropiate crimping tool. Multi-way connector blocks came from eBay I think.

I didn't bother with thin wall, decided to just duplicate what was OEM. So as not to introduce any unknowns.

I didn't bother with a "peg board" or anything like that.

Just took harness off and used directly it as a pattern, simply measure each new wire against the original. I made the mistake of making all the new ones slightly longer, to make sure they reached to wherever, this turned out to often make things more awkward to fit.

Will also need large bore sleeving to contain the bundles of wires.

Also take lots of photos of the original in situ, amazing how you forget how it's supposed to fit.

I found the process quite satisfying to do with a sense of achievement at the end. Big smile












"Chicken nuggets don't dance on a Tuesday."
Back to Top
cugsy View Drop Down
Senior Member
Senior Member
Avatar

Joined: 30 Nov 2016
Location: norfolk
Status: Offline
Points: 861
Post Options Post Options   Thanks (0) Thanks(0)   Quote cugsy Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov 2019 at 13:55
Lots of labels. Dont make anything off till your 1000% sure. Then crimp away.  Get a big sheet of card and tape it down. 
Due to italian electrickery I am saying nowt. Despite nearly giving the Vstrom away the honda has gone...
Back to Top
Mike H View Drop Down
Senior Member
Senior Member
Avatar

Joined: 21 May 2014
Location: East Anglia
Status: Offline
Points: 6930
Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov 2019 at 14:01
I found I could reuse the special connector block housings, e.g. for the regulator, and the ones at each end of the yellow alternator wires – a small screwdriver down the side to push the locking tab down so the connector can be pulled out, and it's exactly the same (or mine was) as the 6mm female receptacle that comes with a 6mm blade type multi-way plugblock.


"Chicken nuggets don't dance on a Tuesday."
Back to Top
Dave P. View Drop Down
Senior Member
Senior Member


Joined: 12 Jan 2015
Location: Northants
Status: Offline
Points: 3120
Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave P. Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov 2019 at 14:15
Does anyone know please what amperage thin wall cable matches the wiring in the standard loom? Quote.

That should be in your Vehicle Wiring Products catalogue in the wire section near the front.
I always just use the bike as a jig when making up a new harness.
TO LIVE OUTSIDE THE LAW YOU MUST BE HONEST.

1971 V7 Special. 1972 850GT.
1970 T120 Bonnie. 2009 500 Bullet.
Back to Top
AdrianW View Drop Down
Senior Member
Senior Member


Joined: 05 May 2019
Location: Bristol
Status: Offline
Points: 177
Post Options Post Options   Thanks (0) Thanks(0)   Quote AdrianW Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov 2019 at 14:39
I've done the odd British bike, but they are rather simpler than a Guzzi.. Nothing magic about it though, wires simply need to be the right length and connected properly at each end.
Vehicle Wiring Products are a good source..

Must admit British bikes don't handle the current (no stsrters, on mine at least) so have never bothered too much about cable specs. Being a cheapskate I got a towing trailer cable (about 5m in length and cut the ends off - gave me lots of colours to play with..
You often find that the original harness had spare / redundant cables.

As others have stated, buy a decent crimping tool, good quality shrink wrap and use lots of lables..

Cheers,
Adrian
Bristol UK
Back to Top
Chris A View Drop Down
Senior Member
Senior Member


Joined: 15 Dec 2018
Location: France
Status: Offline
Points: 156
Post Options Post Options   Thanks (0) Thanks(0)   Quote Chris A Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov 2019 at 17:03
I did my T3 last year as it has non standard features ...apart from the three cables from the alternator ,the starter motor feeds and the mains  from the battery to the ignition switch and then to the fuse box ,I used 16.5 amp thin wall.The bigger cable was the either the 25 or 33 amp .
Back to Top
TheWrongTrousers View Drop Down
Senior Member
Senior Member
Avatar

Joined: 05 Nov 2018
Location: South London
Status: Offline
Points: 373
Post Options Post Options   Thanks (0) Thanks(0)   Quote TheWrongTrousers Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov 2019 at 18:56
It certainly can be done but it is not easy for those to whom matters electrical are not second nature. I replaced so much dodgy old wire in my LM1 that I have a 90% new loom. As Mike says it is very satisfying, but prepare for frustrations. But you need to be very methodical. Here is a link to Greg Benders site where he says something about all this. I found it very inspiring. 


I humbly suggest that you pay particular attention to the section entitled "mental preparation" 

My travails would have been a lot worse had it not been for Greg's words of wisdom.


Serenity Now !!*!**!!
Back to Top
Brian UK View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 13 May 2014
Location: Surrey
Status: Offline
Points: 11857
Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov 2019 at 22:27
Just be aware that max current capacity listed is worked out on the amount the cable heats up. Thus thin wall is rated at a higher current than the older thick wall, as there is less heat insulation so it cools more readily.

BUT on low voltage circuits, the voltage drop is far more important and that is never measured. I would always go for heavier wire than their "specification" for this very reason. You stand a chance of a headlight that actually illuminates the road ahead if you do.

Brian.

Better 5 minutes late in this world than years early in the next.
Back to Top
iansoady View Drop Down
Senior Member
Senior Member
Avatar

Joined: 23 Jul 2017
Location: Birmingham
Status: Offline
Points: 1374
Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov 2019 at 11:04
Originally posted by AdrianW AdrianW wrote:

Being a cheapskate I got a towing trailer cable (about 5m in length and cut the ends off - gave me lots of colours to play with..
Cheers,
Adrian
Bristol UK


Oh no, I thought as  a Velo owner you must be an engineer......

My ES2 came with a similar creative wiring harness. I chucked the whole lot in the bin and started again with the correct colours. Cable from VWP is only about 40p a metre from VWP (I use the 1mm square 16.5 amp stuff for everything on the Norton). Trying to remember which colour you used for what on a dark rainy night isn't my idea of fun......
Ian
1982 V50
1952 Norton ES2
Back to Top
AdrianW View Drop Down
Senior Member
Senior Member


Joined: 05 May 2019
Location: Bristol
Status: Offline
Points: 177
Post Options Post Options   Thanks (0) Thanks(0)   Quote AdrianW Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov 2019 at 12:00
Ian,
I'm afraid not !! Vaguely competant mechanic but not an engineer (I was an IT Tech). 
I have a good friend up the road (Ex RR with a lathe) for that sort of thing !!

Haven't touched the wring on either Velo yet although the MSS could probably do with it sometime. They seem to be mainly "any colour as long as it's black" in the wiring department too... Smile

I always use domestic yellow/green cable for earth cables. It looks a bit odd but at least I can see them easily. Gives rivet counters apoplexy too....
Cheers,

Adrian
Bristol UK
Back to Top
Ben. View Drop Down
Senior Member
Senior Member


Joined: 18 Mar 2015
Location: Lanjaron Spain
Status: Offline
Points: 489
Post Options Post Options   Thanks (0) Thanks(0)   Quote Ben. Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov 2019 at 12:25
I'm not in a position to compare crimping with soldering, but all the wiring looms I made for the Avro Vulcan at RAF St Athan were soldered, and much use was made of heatshrink and sleeving. Beneath the outer sleeve, the wires were bound together with repeated loops of cord at one inch intervals.
I didn't grock electricity then and I don't now,  so worry not, making looms is a purely mechanical process.
If I do crimp, I tin the end of the wire first, but I'm not really sure why ...


Edited by Ben. - 03 Nov 2019 at 12:59
Back to Top
MartinC View Drop Down
Falcone
Falcone
Avatar

Joined: 26 Sep 2019
Location: Sheffield
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote MartinC Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov 2019 at 12:47
Take a look on YouTube for the "m-unit" looks quite simple, have done 2 old British bikes but they are very minimal in the wiring stakes. Have used vehicle wiring products in the past with great service. 
Back to Top
AdrianW View Drop Down
Senior Member
Senior Member


Joined: 05 May 2019
Location: Bristol
Status: Offline
Points: 177
Post Options Post Options   Thanks (0) Thanks(0)   Quote AdrianW Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov 2019 at 13:01
On the British stuff I almost always solder connections. Seems a good idea to me to "tin" the wires if you are crimping, stops the strands fraying and breaking individually..

Cheers,
Adrian
Bristol UK
Back to Top
Mike H View Drop Down
Senior Member
Senior Member
Avatar

Joined: 21 May 2014
Location: East Anglia
Status: Offline
Points: 6930
Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 03 Nov 2019 at 16:19
Originally posted by Ben. Ben. wrote:

I'm not in a position to compare crimping with soldering, but all the wiring looms I made for the Avro Vulcan at RAF St Athan were soldered, and much use was made of heatshrink and sleeving. Beneath the outer sleeve, the wires were bound together with repeated loops of cord at one inch intervals.
I didn't grock electricity then and I don't now,  so worry not, making looms is a purely mechanical process.
If I do crimp, I tin the end of the wire first, but I'm not really sure why ...


If you get the correct crimping tool, the correct matching connectors and suitably sized stranded wire, no problem.

DO NOT solder tin the wire first, the crimping won't work. The stranded wire has to be able to "squash", that means the individual strands have to move. I think a lot of people are afraid that, because it's not soldered, air and water will get in and cause corrosion. This can't happen if the crimp is properly tight (hence why you need the proper tool. Although I have done it successfully with a combination of pliers, long-nosed pliers and blunted side [wire] cutters).

I have used heatshrink for the backs of the connectors in the muilti-way plug blocks, and very useful it is too.




"Chicken nuggets don't dance on a Tuesday."
Back to Top
 Post Reply Post Reply Page  123 4>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.02
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.063 seconds.