Author Topic: Kill Switch 400/4  (Read 2753 times)

Offline smoothoperator

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Kill Switch 400/4
« on: November 09, 2020, 05:18:57 PM »
I'm researching this topic and finding that there is a lot of information, so I'll keep looking. In the meantime could anyone shed some light on a couple of points? Current situation is that kill switch doesn't kill the engine in either of the off positions. Can I test its function without actually firing the engine up, which is tricky at the moment because of intermittent fuel overflow. I have a multi meter. I haven't found a black/white wire in the headlamp shell as yet. As I understand things this wire routes to the coils, so with the ignition on I'd expect to see a voltage, but where to measure it? Looking at stripping the r/h switch unit but even removing this is looking tricky to me at the moment, with wire tight into the handlebars, throttle cables to disconnect and handlebar to remove there is quite a bit to learn. I'm a bit baffled at the moment, any help would be appreciated.

Just noticed the loom from the handlebars routes to underneath the tank so I can eliminate searching in the headlamp shell.
« Last Edit: November 09, 2020, 05:33:04 PM by smoothoperator »
Steve
2017 Triumph Bonneville T100
1977 Honda 400 Four Restored April 2022

Offline Lobo

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Re: Kill Switch 400/4
« Reply #1 on: November 09, 2020, 10:52:13 PM »
You’re on the right track; you need to place the Red probe onto the B/W wire under the tank, and the Black probe onto the battery negative (or KNOWN good Earth). (Black circle in the pic). The ignition will need to be ON.

The B/W wire has two possible connectors you can use; either the one in the ‘boot’ forward LHS of the tank (Blue circle in the pic).... or by the coils where the feed splits (Red circle in the pic). (you do not need to disconnect the connectors, tho’ a slightly lower voltage reading will result)

An odd failure: my early guess is that the kill switch (or it’s wiring) has failed in the past, and the PO has simply directly connected the coils to the ignition, bypassing the kill switch circuit.

To test the Kill Switch functioning, you’ll need to disconnect both its Black and B/W connectors within the boot. (These are both within the Blue circle).
(To set the meter select  the lowest Ohms range, and touch the probes together - you should see close to 0 ohms.)
Now put the probes across the Black MALE and B/W FEMALE connectors of the kill switch, and check its continuity in the OFF / ON / OFF positions. In OFF you should see Infinite ohms (open circuit), and in ON you should see close to 0 ohms.
Wiggle the handlebars / loom whilst doing this check, see if anything changes... bad loom etc.

The Kill switch is indeed a pain to remove / service. As a starter for 10 it might just be worth shooting a good squirt of WD40 into into any nearby switch orifice!

Good luck...

PS - whilst the safety implications are obvious, in this current state of ‘permanent’ Kill function ON you may burn out a coil / flatten the battery when the ignition is ON & engine not running for any length of time.
« Last Edit: November 09, 2020, 11:24:28 PM by Lobo »

Offline McCabe-Thiele (Ted)

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Re: Kill Switch 400/4
« Reply #2 on: November 10, 2020, 08:06:22 AM »
Aside from your mates overtaking you and activating your kill switch it has always baffled me as to its purpose.

I do not recall any of my Mopeds,Scooters or British Bikes having such a device though my memory could be defective. That said if its fitted I want it to work!
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Offline mike the bike

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Re: Kill Switch 400/4
« Reply #3 on: November 10, 2020, 08:18:27 AM »
It's very unlikely that the kill switch could go faulty in this way.  I've had one open circuit,  but never a short circuit.
It's more likely a previous owner has been meddling with the wiring, perhaps to repair an open circuit switch.
Where's that 10mm socket got to?

Offline smoothoperator

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Re: Kill Switch 400/4
« Reply #4 on: November 10, 2020, 09:29:15 AM »
Thanks guys, great help for me to test this now. Meanwhile I have found a smoking gun. I have put an image in below along with a couple of pic's of the coils. There is a disconnected black wire from the r/h handlebar and a likely looking home for it, both circled. The female circled is a double connector which has 1 black/white and 1 black - although the plain plain black is difficult to see in all the grime.

There are 2 other empty females in the bag but these are orange/white and light blue/white.

The only dodgy bit I have arrowed as it is very poorly connected and is thinner than the rest of the wires. This might be a red herring/future issue/no issue.

https://photos.app.goo.gl/AvCtaW7HwqH5YLcx6
Steve
2017 Triumph Bonneville T100
1977 Honda 400 Four Restored April 2022

Offline Lobo

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Re: Kill Switch 400/4
« Reply #5 on: November 10, 2020, 12:25:21 PM »
The 2 photos showing coil connections seem OK to me.
The 3rd photo is a little confusing as things difficult to make out.
But.... it appears that the Kill switch 12v supply (Male / Black) connector has been disconnected and is floating free. (there is potential for a short circuit here - it should be insulated / taped up)
Normally, Black would never be directly connected to Black / White, and because you have this, I (still) reckon the PO has bypassed the (faulty?) Kill switch and wired the coils directly to the ignition. (Ie 12v Ignition Black now directly feeds the coil Black/White supply line.)

(The White wire is normally the 12v supply from the Lo Beam switch to the headlamp bulb, and is not part of this problem. I’ve no idea of Orange / White and Blue / White wires; Orange and Blue are normally L & R Indicator supplies: my guess is your loom may have options for American running lights - which would explain why they’re not used?)

As I see it, you need to ascertain whether the Kill switch is serviceable as described in my earlier post. If not you’ve 2 choices... continue as you are (being mindful of burning out the coils) or replacing / repairing the Kill switch.
« Last Edit: November 10, 2020, 12:28:30 PM by Lobo »

Offline hairygit

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Re: Kill Switch 400/4
« Reply #6 on: November 10, 2020, 02:55:09 PM »
Aside from your mates overtaking you and activating your kill switch it has always baffled me as to its purpose.

I do not recall any of my Mopeds,Scooters or British Bikes having such a device though my memory could be defective. That said if its fitted I want it to work!
The reason was safety, probably to satisfy the U.S. market. If you came off the bike and the engine stayed running it was a fire risk or the engine could rev uncontrollably due to the carbs flooding. If the bike was down on it's left side, you couldn't turn it off as the ignition switches at the time were fitted below the front of the tank, so it gave somebody an easy way to kill the motor.

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Offline Bryanj

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Re: Kill Switch 400/4
« Reply #7 on: November 10, 2020, 03:50:00 PM »
The orange/white and blue/white are the US front running lights, kill switch was just an easy way to stop engine without burning your fingers on the exhaust when fiddling for the ignition switch

Offline smoothoperator

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Re: Kill Switch 400/4
« Reply #8 on: November 10, 2020, 06:55:06 PM »
You’re on the right track; you need to place the Red probe onto the B/W wire under the tank, and the Black probe onto the battery negative (or KNOWN good Earth). (Black circle in the pic). The ignition will need to be ON.

The B/W wire has two possible connectors you can use; either the one in the ‘boot’ forward LHS of the tank (Blue circle in the pic).... or by the coils where the feed splits (Red circle in the pic). (you do not need to disconnect the connectors, tho’ a slightly lower voltage reading will result)

An odd failure: my early guess is that the kill switch (or it’s wiring) has failed in the past, and the PO has simply directly connected the coils to the ignition, bypassing the kill switch circuit.

To test the Kill Switch functioning, you’ll need to disconnect both its Black and B/W connectors within the boot. (These are both within the Blue circle).
(To set the meter select  the lowest Ohms range, and touch the probes together - you should see close to 0 ohms.)
Now put the probes across the Black MALE and B/W FEMALE connectors of the kill switch, and check its continuity in the OFF / ON / OFF positions. In OFF you should see Infinite ohms (open circuit), and in ON you should see close to 0 ohms.
Wiggle the handlebars / loom whilst doing this check, see if anything changes... bad loom etc.

The Kill switch is indeed a pain to remove / service. As a starter for 10 it might just be worth shooting a good squirt of WD40 into into any nearby switch orifice!

Good luck...

PS - whilst the safety implications are obvious, in this current state of ‘permanent’ Kill function ON you may burn out a coil / flatten the battery when the ignition is ON & engine not running for any length of time.

Did the first test and it gave around 11.5V.

Didn't do the second test as the b/w from the handle bar goes to a grey wire rather than another b/w. I have added 3 more labelled images which might help the expert eye.

I can see from the wiring diagram that the ignition to the horn, I think I have this in one of my images. I mention this because the horn button is missing. I opened up the left hand switchgear expecting to see remnants of the horn, however, it is completely missing, 3 cut wires bare the only evidence to its former existence. Given that these are as I understand it unavailable, I will probably be fitting a new, copy left hand switch. Correction, I was thinking of horn button, switch assemblies are available.

New images added:

https://photos.app.goo.gl/AvCtaW7HwqH5YLcx6
« Last Edit: November 10, 2020, 08:04:32 PM by smoothoperator »
Steve
2017 Triumph Bonneville T100
1977 Honda 400 Four Restored April 2022

Offline Lobo

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Re: Kill Switch 400/4
« Reply #9 on: November 11, 2020, 05:45:38 AM »
Hi again.
It would seem there’s a bit more to your wiring dilemma when you talk of cut / bare wires within the L handle bar switchgear, and really you should be considering a complete overhaul of the loom / switches as reconnecting things iaw the book may well just liven up previous cut & dangling wires.
... which was going to be my first suggestion; ie connect the loom up as designed, meaning colours can only connect to the same, and NEVER mismatched. Eg B/W to B/W, Black to Black.... NOT Black to Grey etc. If you’ve (eg) 3 Black Females floating in the headlamp bowl (wherever) and 3 Black Males, you needn’t worry where each is from / going to, you just connect them.
The above said, when checking the functioning of the Kill Switch, you DO need its specific Black feed wire as in total, there are 3 Black wires going to this RH switch gear.. ie the Kill switch, Engine Starter & Headlamp.
It’s all getting complicated - sorry. A quicker check of the kill switch might be to connect the two Black/Greys together, and also ensure ALL Blacks are connected (ie none left floating around). Then, with the Ignition ON, and VOLTAGE Scale dialed in, put the Red probe into the B/W Coil connector, and the Black probe on the battery -ve.... as you did recently. Flip the kill switch and hope to see 0V / 11.4V / 0V.
(I reiterate though. Doing the above MAY liven up some various ‘loose ends’ given your bike seems to have been badly messed with - and cause blown fuses etc)
You might be better to seek local hands-on advice?

Cheers,
Simon
« Last Edit: November 11, 2020, 06:06:21 AM by Lobo »

Offline smoothoperator

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Re: Kill Switch 400/4
« Reply #10 on: November 11, 2020, 08:30:17 AM »
Thanks for this Simon, some very useful information. Wiring issues often result in a can of worms opening up and it's clear I need to really dig into this issue. My plan is to completely strip the bike so currently I'm trying to fix what issues I can rather than face them during the rebuild. That said I might end up with a new loom, new left hand switch, new right hand switch etc so with that in mind I'll go as far as I can with this but if it beats me then I'll take a new tack. For example let's say I buy new handlebar switch gear I would be looking at the problem in a different way, e.g. where is the wire in the loom that I fit this wire from the switch to. Got a free day today so I'll be giving it a good look. By the way the reason I might buy a new r/h switch is because it looks like I need a new left hand one and aesthetically I would want them to match. They aren't stupidly expensive either.
Steve
2017 Triumph Bonneville T100
1977 Honda 400 Four Restored April 2022

Offline Lobo

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Re: Kill Switch 400/4
« Reply #11 on: November 11, 2020, 10:38:06 AM »
Agreed. Often it can be a false economy to patch things that are worn out, and wiring issues especially, are notoriously difficult to fettle on a roadside.
Peace of mind is often underrated!
Good luck...

Offline smoothoperator

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Re: Kill Switch 400/4
« Reply #12 on: November 11, 2020, 12:21:36 PM »
Disconnected both handlebar looms, removed "the bag", cleaned wires so things are clearer. Added 3 images. The first shows that the b/w from r/h switch went into a grey that connects to NOTHING. Another black connects to NOTHING. Also the thin white white wire went to NOTHING. At this point I take a mental decision to buy new l/h and r/h switch, so focus now on planning for this. With that in mind, the r/h switch loom has 7 wires, 6 male and 1 female, b/w. The main loom into which these connect are all female. The l/h switch wires all male. So the odd one out is the b/w. Presumably new switch wires will be the same, leaving me with just one issue, understanding why the b/w is female in both cases?

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

Steve
2017 Triumph Bonneville T100
1977 Honda 400 Four Restored April 2022

Offline smoothoperator

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Re: Kill Switch 400/4
« Reply #13 on: November 11, 2020, 02:27:07 PM »
Just studied the pics, it looks like the PO has removed the kill switch from the wiring as Lobo suspected. For some reason the last pic where you’ve removed all the wires from the loom you’ve left a male black/white wire still connected to a black female. Honda and most other manufacturers used plastic sleeving to cover all wires which held power, these were normally female. So you could disconnect these wires and they wouldn’t short on the frame blowing a fuse. All wires which tapped into this power were uninsulated except for a small covering where the connector was attached to the wire. So if it’s bare it’s usually dead. Now the right hand switch has a covered black/white as when the male blacks are connected it feeds the kill switch, with the switch on power comes back down the black/white hence the insulation. This should connect to the male black/white you can see in the last pic connected to the black, this goes into the loom and comes out again near the coils as a twin female, this feeds the coils, so kill switch off and no power down the black/white so no power to coils, engine stops.

Sorry if this sounds a repeat of some of the advice already given but it explains why Honda did things like this

Thanks, all observations welcome on this one. In the image where I'm wearing a glove, I left the male wire attached to the female b/w just to show how in fact it lead to nowhere. In the next image I have removed it. I still can't see how I connect the female from the switch to the female of the loom without a male to male piece for example. When I install a new handlebar switch, that is. All connections to the left handlebar switch I "get". You can see on images of new handlebar switches, they have the one b/w insulated female connector.
Steve
2017 Triumph Bonneville T100
1977 Honda 400 Four Restored April 2022

Offline smoothoperator

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Re: Kill Switch 400/4
« Reply #14 on: November 11, 2020, 04:48:26 PM »
Yes, just to pint out that is where I found the wire it's not my doing! You've really helped me by focusing on this so thanks again. Looking at the wiring diagram posted by Lobo, I can see that the b/w wire in question should go directly to the female b/w wire from the handlebar switch. It's probably been put where it is to bypass the kill switch and provide a voltage to the coils regardless of kill switch position.

It has also occurred to me that the clever little wiring diagram shows the gender of the termination, triangle for male and rectangle for female. Also where rectangles are joined to each other, then that signifies a double connector.

Searching for both l/h and r/h switches, DS copies look favourite so far.
Steve
2017 Triumph Bonneville T100
1977 Honda 400 Four Restored April 2022

 

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