The Wire Harness Thread - Everything About Repairing & Restoring

[markb]

I brought up some questions on my restoration thread about wire harnesses.  I got some excellent replies from Steve and Wayne and Ash.  There are also a couple of other threads with bits of info here and there so I thought it would be a good idea to try to consolidate everything into one thread.  I think it should include repair methods, materials, parts sources, restoration tricks, -050 conversions, re-wrapping  and anything and everything to do with wire harnesses and related components.

I'll start if off with my original question.  I have a -040 harness that is in pretty decent shape.  I'm looking at options for "cleaning" it up including replacing terminals and yellowed sleeves or finding a way to remove/reduce the yellowing.  One challenge is I haven't been able to source all of the connectors.  I did score some of the standard 3.5mm male and female, original tin-plated terminals from an old Honda dealer but he didn't have any of the multi-pin or right angle ones.  I have found some of the other connectors online but not all of the insulators.  And if I can find insulators there still is the challenge of heat crimping them onto the wires.

Cleaning is another challenge.  I'm looking at options like ultrasonic cleaners but I don't know much about it or what chemicals to use, etc.  There are a lot of questions and I'm sure the answers are out there.

Thanks,
Mark

[ashimotok0]

I need a little time to get my facts together Mark but I will look into cleaning up the old connectors in US cleaner etc.

Vintage Connections are anyone's first port of call because they stock the correct bullets, multi-block Hitachi non-latching connectors, crimp tool, silver-grey sleeving for the starter solenoid etc. Nice family concern to deal with .. but high import duty from us in the UK.

http://www.vintageconnections.com/

I seem to remember my K0 main loom was made by Sumitomo. ( each coloured wire is marked with Sumitomo 1969 ..cool ! )

Here are my sources of other stuff:

Tinning solution ( not tried this as I have old stuff that's great but NLA but it should work if the surface is cleaned and degreased)

http://www.ebay.co.uk/itm/like/221674394658?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&chn=ps&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

10mm glass woven/ silicone impregnated sleeving

http://uk.farnell.com/hellermann-tyton/gss10/sleeving-helaglass-10mm-25m/dp/1674275

Range for other sizes :

http://uk.farnell.com/webapp/wcs/stores/servlet/Search?catalogId=15001&langId=44&storeId=10151&categoryId=700000006007&st=glass%20sleeving%2010mm%20silicone&pageSize=25&showResults=true&pf=110381913


Glossy black sleeving: (Vintage Connections for small quantities or silver-grey version)

http://uk.farnell.com/webapp/wcs/stores/servlet/Search?catalogId=15001&langId=44&storeId=10151&categoryId=700000006007&st=alpha%20sleeving%20black&pageSize=25&showResults=true&pf=110009806,110149521,110381910,110381911

I used clear heatshrink and grey heatshrink for the ends on the alternator sub-harness and the points sub harnesses respectively. The grey is also used on the oil pressure switch cable plus woven glass sleeving.

Vintage connections sell the non-adhesive, black PVC loom tape or it's freely available on eBay.

NEED TO FIND : The thin walled nitrile rubber sleeving for the alternator sub-loom and the HT leads covering. It's around 1mm wall thickness. I do have a lead on it though. Plus the 18AWG glass/silicone woven single cable, in the correct colours, for the alternator coils (high temperature as used in cookers). The same wire is also used on CB350K/CB250K twin, points loom but I think the 750K0 used high temp. PVC yellow and Blue, which  have a source of from' Alpha wire' in the US

RUBBER SOFTENER: Needs to be immersed for a long time (overnight) at 70 degrees C and I think it will only work on Nitrile rubber not PU (Polyurethane). I had an original '69 46k mile  inlet rubber and airbox 'rubber' from my 10/69 K0 analysed and the result was that the inlet was Nitrile & the airbox was PU. This softener definitely does work, I will post pictures of before and after and the part was treated in 2011 and still soft and elastic but it needs long immersion at highish temperature ( I use an old 'slow cooker' to heat the softener in a glass dish  water bath .. if you get an invite for dinner at my house .. then gracefully refrain )

http://www.greatlakes.com/Industries_We_Serve/Building_and_Construction/Other_Building_Materials/Reofos_50


TRY NEWARK IF NO FARNELL STOCKIST  IN YOUR REGION for sleeving etc.

MARK PLEASE PLEASE DON'T BUY ANY OF THIS I WILL SORT YOU OUT ENOUGH FOR A COUPLE OF BIKES AND POST IT FOR FREE TO YOU>>> I OWE YOU ONE !

I will do some more investigations  on the fused clear covers and post back. I am sure I can 'crack' it.

Cheers ... Ash

[Wayne]

Here's where Ash talks about using the hair straightener to fuse the insulator.

http://cb750sandcastonly.com/smf_forum/index.php?topic=213.0

Mark you have 2 maybe 3 rolls of the "non-adhesive, black PVC loom tape" in one of the boxes that went with 576. It's the exact thickness and width.

[ashimotok0]

Problem is with all of that stuff is it comes in bulk. It's fine for me as I stock it for 'the day job' . Perhaps I should put some kits together with a 'bikes worth'. I will put a bit extra in when I send Marks stuff and it he can give any spare away to deserving recipients of his choice !

Ash

[markb]

Thanks Ash!  That is a ton of great info.  I'll be looking forward to more.  Here is a link I've posted elsewhere but this is a good place to have it.  It's a Honda Service Bulletin with parts and instructions for repairing wire harnesses.
http://www.maultechatv.com/techguides/Service%20Manuals/HONDA/Wire%20Terminal%20Supplies.pdf

There was already a really good thread started about "converting" a -050 harness to a -040 here:
http://cb750sandcastonly.com/smf_forum/index.php?topic=1243.0

I probably should have just tacked on to that one but I would suggest using this thread for restoration of harnesses and the other one for the replicas.  Just a suggestion.

[markb]

So I received my terminals yesterday.  I was a little premature in saying I scored.  They were the wrong ones.  They were tin plated but they were 4mm diameter instead of 3.5mm diameter.  I called them back and all they had in the 3.5mm were the brass ones.  So I'm back to looking for a source for the correct ones.  I believe the Vintage Connections ones are brass too.

[ashimotok0]

So I received my terminals yesterday.  I was a little premature in saying I scored.  They were the wrong ones.  They were tin plated but they were 4mm diameter instead of 3.5mm diameter.  I called them back and all they had in the 3.5mm were the brass ones. So I'm back to looking for a source for the correct ones.  I believe the Vintage Connections ones are brass too.

Mark .. I plated my own bare brass terminal  using the plating solution I mentioned. I could try sending you some with the sleeving but not sure how customs would react to little bag of white powder. It does work really well though and immersion only, no electricity involved.


Ash

[markb]

...not sure how customs would react to little bag of white powder.

No worries, I can get some.  If you think it works well I won't worry about trying to find the tin-plated ones.  Thanks,

[ashimotok0]

...not sure how customs would react to little bag of white powder.

No worries, I can get some.  If you think it works well I won't worry about trying to find the tin-plated ones.  Thanks,

Definitely works well Mark. will try to demo.  Any tarnishing can be removed with a quick dip in citric acid solution (used in home brewing & lemons  ) make sure it is well degreased too.

Ash

[markb]

The closer I look at my "good harness" the worse it looks.  I think I'm going to need the sleeve that goes into the headlight bucket.  Can anyone confirm the diameter?  I measure 17mm, which by the way isn't available from Vintage Connections.  I have a piece that is 17mm and just want to confirm that it's correct.

Also the clear connector insulators are very hard.  So far I haven't seen sources for some of the connectors, in particular the right-angle spade connectors.  Changing out all the connectors on the harness is now appearing to be a daunting task.  Even if I can get the insulators to clean up I'm afraid they might not be flexible enough to insert the mating connector.  Ash, do any of your softening methods work on the connector insulators?

[4pots1969]

Hi Mark,

When plastic guards become hard, they are also very brittle, and it is completely irreversible... You won't be able to do anything because they become hard after a while... And it's the same for the insulators in butil between the cylinder head and carburettor, they will stay soft a few months and they become hard.
It has unfortunately parts that could not save... And I even think it is a mistake to try to do... But this is just my humble opinion!
Need an acceptable compromise for your electrical system and restore the parties aged with recent parts in good condition...

Gerard

[ashimotok0]

Well my carb rubbers were treated 5 years ago and not hardened at all.

Mark I have some right angled connectors .. soft covers but a little yellowed but I might be able to get some better ones. I have some much newer looking right angled metal parts than on this photo but they are in my garage somewhere.

On your original bullet covers I think I could soften them but not get rid of the yellowing. I did get the main sleeving for my K0 loom from VC but can't remember the diameter.  Can you cut off a piece of the old stuff and work out the circumference from the length of the unraveled old bit. If you can find out I will get a reel of the correct ID stuff. The covers VC sell are good and work fine but obviously not heat fused and I am still working on that one.

I am ordereing the 10 mm ID  glass sleeve tomorrow please let me know how many bikes worth you need of everything. How many right angled oned do you need ?

AFTER TAKING THE SHOT BELOW I BUNGED THE COVER IN HOT BLEACH AND IT GOT RID OF MOST OF THE YELLOWING (STILL LOVELY AND SOFT) They are a from a friend who is sadly no longer with us. They are from a company called 'Tewel' in the UK in a place called 'Box' (home of the famous Isambard K Brunel Tunnel, in Wiltshire ( probably made in the 60's and long gone now).

Ash

Ash

[patriotcommercial]

I bought some plastic tube covering for wire harness from a company called US Plastics.  The stuff I bought was shinny black on the out side, looked exactly correct.  The wall thickness was greater than the stock stuff.  The outside diameter was exact correct.  When it arrived I was bummed out cause it looked different due to the wall was thicker.  However when I installed it on the harness you could not see the wall thickness, it looked perfect !

[markb]

Was the outside diameter 17mm?

[ashimotok0]

Mark .. I am posting your glass/silicone impregnated  sleeving, right angled terminals etc today  .. sorry for delau. BTW I am resurrecting the hot fused clear bullet connector covers again.. watch this space !

Ash