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New starter/kill switch assembly

Herb400t

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Location
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I'm replacing my old starter switch with new Domino switch but I can't quite work out proper wiring. I did some online research and found an old post from the old Honda Twins forum that sorta explained... but not really.
So I'm hoping that someone might be able to tell me which new wire to connect to which old wire. There are five wires on each side so I'm hoping it will be that easy...??

Also, is there somewhere on the forum where I can find an explanation on how to read switch continuity diagrams (bottom diagram on attached). It seems like it must be simple but, since I'm also simple, I've never really had the "ah ha" moment. and very related, is there a post somewhere explaining all the the abbreviations contained in these diagrams? I THINK I sorted out a few and Jim explained some to me in past but I'm still not sure on many; "W"? "TL1" TL2" ???, etc. "HL" on particular has me a bit stumped; "headlight"?? But why then an "HL" on starter/kill switch?

Thanks!
Screen Shot 2022-09-09 at 4.28.54 PM.png
 
The headlight power goes through that switch, the lights or normally on with the key switch in on position, the starter button kills the power to the lights and switches it to the starter while cranking the engine.
 
Mike,
Thanks for insight, all makes sense. (And I now vaguely remember reading something about cutting power to headlight at start-up, but ages ago...I've been working on this bike for 6 years now). Do you have any advice on which new wires to connect to old wires? From what I can decipher, new Domino switch seems to have three wires associated with the on/stop/kill switch and two with the starter button. But it looks like Honda wiring is opposite; two with on/stop/kill and three with starter button.
 
IIRC, the kill switch on the SOHC 400/450 models that use CDI ignition is simply shorting the black with white wire to ground. The switch assembly you bought is probably designed to disconnect ignition power to the typical battery/coil ignition.
 
TL1 is taillight in normal key on position, TL2 is taillight on in key Park position
IG is ignition, HL is headlight, don't recall W
Looking at the switch diagram top one.
Run/Kill switch:
Black will not be connected.
Blue will connect to Honda Black w/White
Black w/Yellow will connect to Honda solid Green

Start Button:
Black w/White will connect to Honda Black
Orange will connect to Honda Yellow w/Red

This leaves no power to the headlight. By connecting Honda Black to Honda Black with Red you will have fulltime headlight controlled by the ignition key, it'll stay on while cranking. To correct that will require a relay and different wiring
 
Thanks Jim! I have studied the two wiring diagrams endlessly and have drawn up many "connection scenarios".... NONE of them matched up with your instructions.

Just so I understand headlight power issue, it sounds like I will need to connect Honda red/black to Honda black so that I have functioning headlight. BUT as soon as I turn key in ignition, headlight will come on and stay on AND the start button function of cutting power to headlight at start up with no longer work. Is that right?

BTW: I did finally find a youtube video that explains the continuity diagrams in original Honda wire diagram. Now I finally comprehend
 
Thanks Jim! I have studied the two wiring diagrams endlessly and have drawn up many "connection scenarios".... NONE of them matched up with your instructions.

Just so I understand headlight power issue, it sounds like I will need to connect Honda red/black to Honda black so that I have functioning headlight. BUT as soon as I turn key in ignition, headlight will come on and stay on AND the start button function of cutting power to headlight at start up with no longer work. Is that right?

BTW: I did finally find a youtube video that explains the continuity diagrams in original Honda wire diagram. Now I finally comprehend
That's correct. Which also means if you have weak battery you may not get it to start. I'll figure out the relay and post here.
 
OK, get this relay https://www.stockwiseauto.com/bosch...Oc7smXon9HnsCxR8WzFVk_0hApuxD5AaAjCpEALw_wcB&
Wire connections:
Headlight
Honda Black to 30
Honda Black w/Red to 87
Starter solenoid
Yellow w/Red from the switch to 85
Yellow w/Red to the solenoid to 86
You'll be splitting the Yellow w/Red to make the connections.
What happens is when you push the switch power goes into the relay and splits part of it bypasses the coil and the rest triggers the coil to open the circuit from 30 to 87 killing the headlight. Once you release the switch the headlight circuit is completed again.
 
Headlight power lead needs to connect to terminal 87a (normally closed terminal), triggering the relay will break the connection between 30 and 87a and kill the light.
 
Jim,

I thought I posted a response yesterday but maybe I failed to hit the proper button, Anyhow the response was "Thanks!" and "watch this space because I'm sure that installing the new relay will not go smoothly and there will be additional cries for help"

Mike thanks for your additional pointer

David
 
Jim,

I thought I posted a response yesterday but maybe I failed to hit the proper button, Anyhow the response was "Thanks!" and "watch this space because I'm sure that installing the new relay will not go smoothly and there will be additional cries for help"

Mike thanks for your additional pointer

David
We'll be here waiting for the success or help wanted post.
 
Jim, Mike,

Can you do me the favor of checking the attached wiring diagram to see if it's matches with your instructions above?

also, a few remaining questions:

The black/red wire use to run to start/kill switch. In new wiring scenario, it will run to 87a on new relay. I'm assuming it ends there and, since I want to mount new relay at back of bike near starter solenoid, it will end up being much shorter wire. does that sound correct?

The red/yellow wire splits at new relay; the end from switch connects to 85 on new relay, other side runs from 86 to starter solenoid. again, is that correct?

lastly, the black wire from switch will connect to 30 on new relay. BUT the wire branches off in a lot of places. does it matter where new relay gets spliced into that "network" of black wires?

Thanks again for help and patience!
 
Jim,

hanks for confirming. BUT, on that black wire; can I attached it to new relay at any spot in the "Black Wire Network"? (which sounds like it should be a movie starring Keanu Reeves)

DH
 
I would ground terminal 86 and connect the starter solenoid wire to terminal 87, in case the relay trigger circuit won't pass enough current to work the starter relay.
 
Moved the relevant posts to this thread, probably will delete a couple.
Yes, the Black wire is battery voltage switched on/off by the ignition so anywhere is fine.
I like Mike's idea of wiring.
 
Jim, Mike,

soooooo, I'm at wits end.

History: this bike is the very first motorcycle/engine/wiring/etc project I've ever taken on. I decided about SEVEN years ago that a motorcycle restoration/modification project would be a great hobby as I neared retirement age. So I bought this bike for $400 and started in. I would say that about two years ago, it changed form; went from a motorcycle to an albatross. This simply comes down to me biting off way more then I can chew. WAY too many mods for someone with such little experience.
But I've come too far, made way too many mistakes--some I've actually learned from--and spent way too much $ to give up now.

That all explained, its probably pretty close to being complete... I just cant resolve wiring. I actually thought I had it all button up a couple of years ago but then I did something stupid. I had installed a new bucket headlight and was struggling to fit connectors inside so I decide to change out the large NEW connectors for slightly smaller ones. That done, suddenly nothing seems to work.

Here is a list of mods to electrical system:

New Domino starter switch AND light switch
New headlamp (with a parking lightblub)
New coil
New Reg/rectifier
New Turn signals
New starter solenoid
New speedo and tach
New levers (so new brake switch and clutch switch)
New 12V Shorai lithium battery
and connectors...

AT MOMENT, the problem is sorting out the wiring for new light/turn signal switch. This thread started with my troubles wiring new Domino starter/kill switch. You guys helped solved the missing function of momentarily killing power to headlamp during start by adding a relay. But now, after two days of pondering original bike wire diagram AND lights/turnsignal switch wiring diagram, I'm wondering IF relay to momentarily kill headlight was needed. New Domino switch has a headlamp "off" position but--I THINK that in original setup, the headlight and taillight came on as soon as key was turned on (which would then explain need for momentarily killing power to headlamp). BUT if new switches allow for bike to start WITHOUT headlight being on, is relay necessary?

It's all a mess and there are times when my head feels like it's going to explode.

I called a local bike repair shop to ask if they had anybody who might want to consult--for a fee--in their off-hours. I could see the guy's eyes roll OVER THE PHONE and it was suggested to me--in a not all that polite fashion--that I might be crazy.

Do either of you have any suggestions on how I might get expert help beyond this forum? I ask that because I think the entire electrical system needs a good once-over by a pro which I think is too unwieldy a proposition to try to tackle on this forum

lastly, here she is (last year, progress has been made since):Bike.jpg
 
I feel for you and fully understand where you're coming from. While the forum isn't ideal for working thru these issues it's probably the best that's available, hands on would be ideal. Finding a local motorcycle tech that can help is unlikely since they aren't trained/taught any of this stuff anymore and anything older than 10 years is obsolete tech as far as they're concerned. So that said, let's see what we can accomplish.
First up is to resolve the new smaller connector problems. I'm guessing the you have the correct crimper tool for the new connectors, if not then that is needed. I would go thru each one using a VOM with a needle probe for one lead. https://www.ebay.com/itm/234062601606 so you poke into a wire with it and then connect to the connector in question and see if there is a complete zero resistance reading. Anything open or more the .5 ohm resistance need repair. When I do new connectors I cover the wire and connector with soldering flux, crimp it and then add a touch of solder. Overkill? sure but I know I have a good connection that's not going to loosen up. I can't tell you the number of times I've thought I had a good crimp only to pull the wire right back out.

Note: mark each needle probe point so when you're done you can go back and wipe a smear to silicone sealer into the hole to seal it.
 
Thanks Jim,

I've had A LOT of practice crimping terminals and I feel like my technique is pretty good. I have considered also soldering as you suggest, but felt like it was... well...overkill. AND, I may have exaggerated when I said "nothing seems to work". Some things do, see below

But after I sent earlier text, I realized that what I really should have explained is that I'm afraid the approach I've been taking--asking specific questions about specific discrete elements of electrical system on forum--might just be too piecemeal, in that without a clear picture of ALL the mods, some things that were originally wired one way might be best wired a slightly different way. ??

Right now my problem is wiring the new Domino light/turn signal switch into existing wire harness.

I have turn signals and horn working (beep, beep). The old switch--as I'm sure you're aware--has a two position light switch; low and high. But new switch has three positions; off, low and high (as well as passing switch--momentary bright light). So I'm wondering if that function on start/kill switch that momentarily kills power to headlight is really necessary considering that there might be a way to wire switch(es) so that bike can be started with headlight off. ?? My guess is that might also involve modifying how the ignition switch is wired???.

I need to track down a clean version of the wiring diagram for Domino light switch (too maybe scribbles/erasures on my hard copy) and I'll post it along with portion of original bike wire diagram that includes connector to old light switch.

Thanks again for help and patience!
 
I know little about the SOHC 400 models but IIRC the ignition switch is just a 2 position (possibly with the Park feature if they hadn't gotten rid of it by then) so it's basically and On/Off switch, first and second positions. So, you could wire the headlight for all 3 positions of the new switch because the older twins had the same style switch before the government mandated headlight on all the time happened. Of course, that also depends on the inter-wiring of the kill switch, on some aftermarket switches the kill switch also kills the starter from turning.
 
It can definitely be wired without the relay.
Clean wiring diagrams of all the new components will be good. From there we can figure out exactly what's needed to get all the electrical sorted.
 
The ignition switch has three positions; off, on and park. My new headlamp has two bulbs, main (low and high) and small parking light.

I was wrong on Domino switch tho, it essentially has four positions: off, parking, low, and then a separate red push-in switch for high beam. It also has a momentary (not sure that's the correct term) switch for "passing light" which is just the high beam

I located the wire diagram for Domino light switch. I just need to figure out how much of the Honda's original wire diagram I need to include here. Will post before end of day. (Day job has me very busy--not retired yet--so it's getting in way of my hobby.)
 
From that description it shouldn't be too big a deal, the functional results will mostly depend on how the switch really operates electrically. IOW, does the parking bulb stay on when you go to low beam or does it go off, little stuff like that.
 
gentlemen,

So sorry for the long pause... i got hit with a virus that knocked me out for last 3-4 days and, even now, only at about 50% (Strongly recommend to anyone reading who is over age of 50, get the two-does shingles vaccine! 'cause shingles suck!))

I've attached the following:

The wiring diagram for new Domino light/blinker switch
A portion of the original wiring diagram for the Honda
and, just as a reminder; I've attached the start/kill switch (also Domino) diagram AND a hand drawn diagram of new relay added to start/kill per earlier instructions

On new light/blinker switch, there are essentially three switches that control various aspects of lights:

"sliding" switch with three positions; off, parking (I think), and low beam
A red "push-in" switch that turns on high-beams
and a momentary "Passing" switch that turns on high beams when depressed

Original switch had only two positions; low and high.

On new switch, I have horn and turn signals resolved, so I just need to resolve the various light switches. (I have turn signal indicator resolved as well, with new diode, per Jim's recommendation, since there is only one indicator light that activates for both left and right)

NOTE that on original Honda diagram I added black and brown wires coming from a separate small, parking bulb in headlamp. Headlamp is new and parking bulb is a new element that was not on original bike.

Lastly, as I mentioned above, I'm a bit concerned that the relay that I added to wiring of start/kill switch might not be necessary now since headlight MAY not come on when key is turned in ignition as it did originally.

Any advice/help wiring new switch would be greatly appreciated!

DH DOMINO_LEFT_SWITCH_HOUSING.jpgHonda CM400T Wiring Diagram 1979.jpgScreen Shot 2022-09-09 at 4.09.23 PM.pngNew Switch Wiring.jpg
 
I'm pretty sure this will give you what's needed. No relay used.
Starter:
Honda Black to Switch Black w/White
Honda Yellow w/Red to Switch Orange

Run/Kill: Because this is a grounding circuit and the switch is set as a power supply the switch operation will be backwards.
Honda Black w/White to Switch Black
Honda Green to Switch Blue
A relay can be used to make the switch operation normal

Headlight:
Honda Black to Switch Green w/White
Honda Dk. Blue to Switch White for Hi Beam
Honda White to Switch Black for Lo Beam

Flash to Pass:
Honda Black to Switch Green
Honda Dk. Blue to Switch Blue w/White

Since the park light and instrument lights are controlled by the Ignition switch just use the extra Brown lead found in the headlight bucket. That's it's original use.
 
Jim, Thanks much for all of this -- especially the prompt reply, which I hardly deserve!

I think my next step is draw all this out and then I'll post for you to confirm

One of the things that threw me on headlight/blinker switch is that there are:

Green/black wire
Green/white wire
and
2 green wires

But they are all wired together in the Domino wire diagram creating what I thought was one "big" ground wire. But if that was the case, why wouldn't they all just be green (rhetorical Q, no need for an answer)

anyhow, thanks for your efforts, much appreciated!

David
 
I'm pretty sure this will give you what's needed. No relay used.

Headlight:
Honda Black to Switch Green w/White
Honda Dk. Blue to Switch White for Hi Beam
Honda White to Switch Black for Lo Beam

Flash to Pass:
Honda Black to Switch Green
Honda Dk. Blue to Switch Blue w/White

Since the park light and instrument lights are controlled by the Ignition switch just use the extra Brown lead found in the headlight bucket. That's it's original use.

Jim, finally have had time... and energy... to sort out your instructions. I am uncertain about a portion of them, tho.

On "Headlight" section
With "Honda Dk. Blue to switch White," are you referring to the Dark blue wire that comes directly from headlamp? rather than the Honda 8 pin connector (which doesn't have a dark blue wire). Same goes with "Honda white" and "Honda black"

same uncertainty on "Flash to Pass." there is no "Honda black" coming from original headlamp and the black wire at connector in original diagram sorta "dead ends" at connector, does not lead to switch.

Lastly, at that 8 pin connector--there is a black/yellow wire that use to lead to switch (labeled "HL1" at switch) but isn't mentioned in your instructions. I'm guessing that it's no longer necessary since it may have had something to do with cutting power to headlamp when start button is pushed. ? and there's also a brown/white at that connector that used to lead to "TL" on original switch. Guessing "TL" is "tail light" and I just need to wire it much like parking light so that it turns on when ignition key is turned. ??

and just so you get some sense of the rabbit hole I fell into about 4-5 years ago--and can't seem to get myself out of--see attached. It shows about half of the self-drawn wire diagrams I've made in an attempt to extricate myself from this mess.
WiringChaos.jpg
 
Answers in Blue
Jim, finally have had time... and energy... to sort out your instructions. I am uncertain about a portion of them, tho.

On "Headlight" section
With "Honda Dk. Blue to switch White," are you referring to the Dark blue wire that comes directly from headlamp? rather than the Honda 8 pin connector (which doesn't have a dark blue wire). Same goes with "Honda white" and "Honda black"
Yes, Honda Dk. Blue and Honda White are the headlight wires. Honda Black is a harness wire, it's power ON with the key.

same uncertainty on "Flash to Pass." there is no "Honda black" coming from original headlamp and the black wire at connector in original diagram sorta "dead ends" at connector, does not lead to switch.
You'll add a wire from the Honda harness Black.

Lastly, at that 8 pin connector--there is a black/yellow wire that use to lead to switch (labeled "HL1" at switch) but isn't mentioned in your instructions. I'm guessing that it's no longer necessary since it may have had something to do with cutting power to headlamp when start button is pushed. ? and there's also a brown/white at that connector that used to lead to "TL" on original switch. Guessing "TL" is "tail light" and I just need to wire it much like parking light so that it turns on when ignition key is turned. ??
I wrote the instructions with out having the headlight turn off with starter use. Simpler wiring w/o a relay involved.

and just so you get some sense of the rabbit hole I fell into about 4-5 years ago--and can't seem to get myself out of--see attached. It shows about half of the self-drawn wire diagrams I've made in an attempt to extricate myself from this mess.
We've all been down the rabbit hole at some point, your diagram isn't bad. Individual colors makes it easy to read, usually people use a pencil so every wire looks the same.
 
Jim,

I drew up a new wire scheme for front end and I'm hoping you check it over as well as answer some..well, many... remaining questions.

Two attachments:
One shows new diagram
second shows same diagram with various areas circled where I have following questions:

#1. there is a yellow wire and a green/black wire on new Domino switch that don't seem to have a function as far as your instructions. Are they not needed? or does green/black just get wired as a ground?

#2. I'm not quite sure what to do with black wire coming from parking light, ground or should it be wired into black other blacks in main harness?

#3 At connector A, which is the bottom most connector on original diagram (I've label the four connectors "A" thru "D" to help me keep them straight. I've labeled actual connectors on bike with paint pen), there is a brown/white and a black/yellow wire that don't seem to be needed. From what I can tell, Black/yellow was part of the system that killed power to head lamp when starting (along with red/black wire on start/kill switch). Brown/white --I THINK--part of tail light and instruments lights and prodivides power when ignition key is turned. so maybe it has no need to be connect to headlight/blinker switch?

#4. Can you confirm that the blue/black yellow/black and two blacks--one from speedo, one from tach--are all grounds? Note that wire diagram of speedo labels solid-color wires positive and solid/black as negative.

#5. Can you confirm that red/black and green/black get wired to black at connector "C"? I'm taking my cue from original Honda diagram.

#6. I have a black wire coming from right brake lever switch. In original Honda, it was wired to blacks. There is a brown/blue wire at connector D that isn't in use, but--and something I can't quite get my head around--in Honda diagram, brown/blue connected to blacks at connector D. So can I run my black from break lever switch directly to brown/blue OR does brown/blue need to get wired into the blacks?

Lastly

#7. I think the red/black wire is now a "remnant" from temp power kill to headlight function and is unnecessary at this point. It connects with black/yellow at fuse box and black/yellow runs to light/blinker switch (see #3 above). I/m guessing those two wires can be eliminated from harness all-together. yes?

THANKS so much for time and patience. and please answer at your leisure


WireDiagram11-7.jpgWireDiagram11-7_w:Qs.jpg
 
Blue answers
Jim,

I drew up a new wire scheme for front end and I'm hoping you check it over as well as answer some..well, many... remaining questions.

Two attachments:
One shows new diagram
second shows same diagram with various areas circled where I have following questions:

#1. there is a yellow wire and a green/black wire on new Domino switch that don't seem to have a function as far as your instructions. Are they not needed? or does green/black just get wired as a ground?
Cap those 2 wires, not needed

#2. I'm not quite sure what to do with black wire coming from parking light, ground or should it be wired into black other blacks in main harness?
That is a ground, Honda Green

#3 At connector A, which is the bottom most connector on original diagram (I've label the four connectors "A" thru "D" to help me keep them straight. I've labeled actual connectors on bike with paint pen), there is a brown/white and a black/yellow wire that don't seem to be needed. From what I can tell, Black/yellow was part of the system that killed power to head lamp when starting (along with red/black wire on start/kill switch). Brown/white --I THINK--part of tail light and instruments lights and provides power when ignition key is turned. so maybe it has no need to be connect to headlight/blinker switch?
Black w/Yellow isn't used. Instrument back lights should go to Honda Brown w/White

#4. Can you confirm that the blue/black yellow/black and two blacks--one from speedo, one from tach--are all grounds? Note that wire diagram of speedo labels solid-color wires positive and solid/black as negative.
Unless you're running LED bulbs + - don't matter. Yes, those go to ground.

#5. Can you confirm that red/black and green/black get wired to black at connector "C"? I'm taking my cue from original Honda diagram.
Yes, those go to Black. Unless you have LED bulbs
#6. I have a black wire coming from right brake lever switch. In original Honda, it was wired to blacks. There is a brown/blue wire at connector D that isn't in use, but--and something I can't quite get my head around--in Honda diagram, brown/blue connected to blacks at connector D. So can I run my black from break lever switch directly to brown/blue OR does brown/blue need to get wired into the blacks?
Honda used a jumper wire to power the Brown w/Blue so that wire does need to go to Black

Lastly

#7. I think the red/black wire is now a "remnant" from temp power kill to headlight function and is unnecessary at this point. It connects with black/yellow at fuse box and black/yellow runs to light/blinker switch (see #3 above). I/m guessing those two wires can be eliminated from harness all-together. yes?
Correct, Red w/Black isn't used
Do Not remove any excess wiring until you've got everything connected and working properly. Even then I would hesitate to do that in case the switches fail and you have to go backwards to stock.

THANKS so much for time and patience. and please answer at your leisure


View attachment 18448View attachment 18449
 
Thanks for help! just one clarification on this in Q #6:

Honda used a jumper wire to power the Brown w/Blue so that wire does need to go to Black"

If I understand correctly, both the Brown/Blue AND the Black from brake lever need to connect to Black. Is that correct?
 
Thanks for help! just one clarification on this in Q #6:

Honda used a jumper wire to power the Brown w/Blue so that wire does need to go to Black"

If I understand correctly, both the Brown/Blue AND the Black from brake lever need to connect to Black. Is that correct?
Yes, if you follow the Honda wiring diagram you'll see the Brown w/Blue goes to the fuse block as a power feed.
 
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