Kill Switch 400/4

[Lobo]

... these wiring diagrams are a mine of information. If you know how to use them they can save you a great deal of work.
Eg, the new LH switchgear you’ll be fitting. If needing info on what the switch operation connects to where, you’ll find that bottom LHS. It shows that the switch in LO position connects the B/Y to White, in mid position it connects B/Y to both White & Blue,
And in HI it connects B/Y to Blue.
The Horn switch. In OFF (Free) ... zip. Push it and Black is connected to Green. Slide it and Black is connected to White.
And so on.

In ‘opening up’ the loom bits and cleaning the wires you can only make your whole job easier - it’s so hard to trouble shoot when colours appear from nowhere and disappear likewise.

From what I see the basic loom looks good; but if in doubt (as you dig into it) it might be worth replacing as so much of it hidden / inaccessible once embedded into its various runs.

[smoothoperator]

I bought a pair of switches for the 400 four a while ago, you want me to look if I still have them, genuine switches are always better than copies

Please do, where possible I am trying to keep the bike genuine without going over the top.

[smoothoperator]

I removed the right hand switch so that I could identify the black wire from the kill switch for checking continuity with the black/white from the other side of the kill switch. Still not sure why Honda used 3 black wires rather than colours as once you've fed them through the bars you wouldn't know which was which. Anyway took enough apart to identify the 3 black wires and then test the kill switch. No continuity in any of the 3 positions. Took off the kill switch and the fault can be seen in the photo I have added. There is a shoulder of plastic next to the metal contact preventing it from touching the the 2 contacts in the switch body. It looks like it has melted at some point. I've removed this shoulder and now I've put it back together it works OK. As to whether it'll work long term I don't know. The wall either side of the contact has thinned on one side, this being where the plastic must have melted to form the shoulder.

https://photos.app.goo.gl/AvCtaW7HwqH5YLcx6

[Lobo]

Well done... it’s always satisfying to find the issue. Your call (obviously!) as to whether you accept the fix, but at least if you do you now know how to facilitate a bodge to get you home. (ie connect a Black to the coils B/W!)

[Bryanj]

It doesnt matter about the blacks they are all power feeds to something so dont need different colours, only a problem when you get a melt like yours, which i have seen on ignition switches but never a kill switch.

[Lobo]

Black signifies Ignition switched 12v.
Let alone confusing, they’d run out of options if every ignition switched 12v component on the bike used a different colour.

You don’t mention the resistance you found in the switch continuity check (after your fix) - this is significant as if high, it could lead to more melting and a false economy. If melting has occurred, it could perhaps suggest an Earth short in the B/W lead between the Kill switch and rubber boot area. Might be worth a check? (Kill Sw should be disconnected from loom, and move the loom / handlebars whilst doing so.)

A good reading will be ‘infinity’ ohms, a bad reading 0 ohms...

[smoothoperator]

That makes sense. Just nipped out to do it, the switch is off the bike at the moment however that didn't stop me giving the wires a wiggle. Both off positions consistently giving infinity and on position giving zero.

[mike the bike]

You're not going to dismantle a switch and not clean the contacts.

[smoothoperator]

I have cleaned the contacts. There is an image of them in the link above. I'm looking for dielectric grease before I reassemble the rest of the switch. Whilst I'm at it also looking for bullets, crimper etc ready for more work on the electrics. I have received a new head lamp and need to wire that in.

[Lobo]

... just beware that the old Honda bullet connectors are smaller than what is commonly sold as ‘replacement bullets’. Off the top of my head I don’t know the specs.... perhaps someone can chip in with advice / best supplier here?

[McCabe-Thiele (Ted)]

... just beware that the old Honda bullet connectors are smaller than what is commonly sold as ‘replacement bullets’. Off the top of my head I don’t know the specs.... perhaps someone can chip in with advice / best supplier here?

I think these were the ones I used 3.9 mm they do the female side as well. My old wiring loom is a bit of a mess it had the later 4.0 mm connectors in some places that had been made to fit by crushing the female side on the loom to make a contact!

https://www.ebay.co.uk/itm/Non-Insulated-Brass-3-9mm-Bullet-Connector-Terminals-Covers-Japanese-Type/332248892672?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

[Lobo]

Mac... apologies but I’m not so sure - I reckon my old Hondas use 3.5mm connectors. Smooth, obviously you’re going to have to do your homework, I’m not saying Mac is wrong, nor that I’m right! Aargh.

[McCabe-Thiele (Ted)]

I stand corrected Lobo I am wrong you are right - I've just re-checked my old loom (again) in a few different places- it has a mixture of 3.9 mm and 3.5 mm male & female connectors!

Looking at the corrosion and insulating sleeves I think many of the originals have been replaced with 3.9 mm - a long time ago as they are green inside!

I'll be ordering some 3.5's now for when I connect the peripherals to the new loom.

[McCabe-Thiele (Ted)]

On my first few searches e bay does not seem to list any 3.5mm connectors.

[Bryanj]

If you are fitting a new loom it may not have that size fitted