Topic: CB750 right hand side switch gear compatibility ?

[Toxic]

HI there

I have a partsnmore wiring harness for a 73-75 cb750 and I want to know if it is possible to wire a right hand side switch to it.
I have a NOS from a 69- 70 and before I start to dremel the cut out to run the wire loom outside of bars I want to make sure it will work with some modification.

This is the switch.


-wire colours are:
-yellow with red stripe
-solid black
-white
-black with white stripe
-another solid black
-brown with white stripe
-solid blue

This is the wiring diagram that pertains to this switch



This is the wiring diagram for the harness I have.  The PartsNmore 73 to 75


The main difference I can see is that the switch I have ( 1969 - 1970 ) the starter button grounds out in the switch housing itself,  I think.

So will I be able to make this work?

Thanks for all the input.

[Bill/BentON Racing]

Yes.Bill

[HondaMan]

The obvious part: the OFF-LOW-HI headlight switch negates the need for the LO-HI beam one on the left side, which was how the 73-75 was wired.

The not-so-obvious part: yes, the START switch grounds to the handlebars. This was pre-'safety module', as outlined in my book: in the 73-75 harness, this means that you must connect the BLACK wire to the solenoid's GREEN-RED wire to supply Ignition power to one side of that solenoid, then you can connect the YELLOW-RED from that START button to the other side of that solenoid, and it will work fine.    And throw away the safety module...

In the 73-and-later harness, there are BLACK-WHITE and BLACK-RED and BLACK-YELLOW wires that you can now ignore, or count as spares, because they run from the K3 OFF-ON headlight switch and START button to the K3-K6 fuseblock, then back to the headlight, and to the left handlebar, which you do not need: just connect the BLACK to your new headlight switch in the headlight bucket and use a single 15 amp bladed fuse between the RED that goes to the Keyswitch and the bike's battery. (BTW: where did you get that switch? I need one for my bike, too...)

A word of caution: if you are using aftermarket (non-Honda) keyswitches, they are almost universally 8 amp switches to which someone has attached a 750 connector. These switches will melt down internally or unsolder the RED lead on the back of the switch over time, as the 750 runs about 8-9 amps all the time (Honda' switches are 15 amp type). So, install a relay somewhere, like under the seat, and use the switched BLACK wire from the keyswitch to turn on the relay coil: connect the RED to one side of the relay's NO contacts and the bike's BLACK Ignition circuit to the other. In about a week, I will be offering kits to do this, for about $25, with instructions.

[Bill/BentON Racing]

Hondaman,I knew you would give him the detailed answer,would take me 2 days to type that much,and couldn't do it near as well,WOW,can't wait for your book,great info as usual,I'll PM you on sprocket,I live in Atlanta,might work,also congrats on the new kit,(needed badly)Thanks and Good Luck on switch install.,Bill

[Toxic]

Great detailed response and fast.

The obvious part: the OFF-LOW-HI headlight switch negates the need for the LO-HI beam one on the left side, which was how the 73-75 was wired.

I have a NOS left side switch as well so at least I won't have to mod it.

The not-so-obvious part: yes, the START switch grounds to the handlebars. This was pre-'safety module', as outlined in my book: in the 73-75 harness, this means that you must connect the BLACK wire to the solenoid's GREEN-RED wire to supply Ignition power to one side of that solenoid, then you can connect the YELLOW-RED from that START button to the other side of that solenoid, and it will work fine.    And throw away the safety module...

I have two black wires coming off of this switch, one from the kill switch and one from the headlight high/low/off.  Are you saying to connect the BLACK wire from the kill switch to the starter solenoid's GREEN-RED?  Sorry if this seems dumb but I am not a electric guru, I don't want to fry something.

In the 73-and-later harness, there are BLACK-WHITE and BLACK-RED and BLACK-YELLOW wires that you can now ignore, or count as spares, because they run from the K3 OFF-ON headlight switch and START button to the K3-K6 fuseblock, then back to the headlight, and to the left handlebar, which you do not need: just connect the BLACK to your new headlight switch in the headlight bucket and use a single 15 amp bladed fuse between the RED that goes to the Keyswitch and the bike's battery.

OK this part I understand.

(BTW: where did you get that switch? I need one for my bike, too...)
Ebay - paid way too much but I hadn't seen too many come up for sale.

A word of caution: if you are using aftermarket (non-Honda) keyswitches, they are almost universally 8 amp switches to which someone has attached a 750 connector. These switches will melt down internally or unsolder the RED lead on the back of the switch over time, as the 750 runs about 8-9 amps all the time (Honda' switches are 15 amp type).
Good to know I hadn't heard of this before

So, install a relay somewhere, like under the seat, and use the switched BLACK wire from the keyswitch to turn on the relay coil: connect the RED to one side of the relay's NO contacts and the bike's BLACK Ignition circuit to the other. In about a week, I will be offering kits to do this, for about $25, with instructions.

I'm going to have to stand in line for one of these kits.

Thanks for your help with this

[Toxic]

HondaMan book???

I definitely will need to get one.

I'm sure you will let us know when it is available.

[HondaMan]

The not-so-obvious part: yes, the START switch grounds to the handlebars. This was pre-'safety module', as outlined in my book: in the 73-75 harness, this means that you must connect the BLACK wire to the solenoid's GREEN-RED wire to supply Ignition power to one side of that solenoid, then you can connect the YELLOW-RED from that START button to the other side of that solenoid, and it will work fine.    And throw away the safety module...

I have two black wires coming off of this switch, one from the kill switch and one from the headlight high/low/off.  Are you saying to connect the BLACK wire from the kill switch to the starter solenoid's GREEN-RED?  Sorry if this seems dumb but I am not a electric guru, I don't want to fry something.

Both of those BLACK wires will connect to a female BLACK in the headlight (i.e., match those colors). The Starter solenoids' GREEN-RED wire should connect to a BLACK wire somewhere under the seat: a convenient spot is to make a little 3-way pigtail off of the voltage regulator's BLACK wire with one end being a female 1/4" spade connector, one end being a 1/4" male spade connector, and one end being a female plug socket (3.5mm size, like the rest of the bike: steal one from your old harness): one end will then connect to the regulator, one end to the same BLACK that used to be on the regulator, and the free end will now go to the Starter solenoid (GREEN-RED). The other wire on that solenoid will be YELLOW-RED, which will go to the START button on the handlebars. This color of wire should be available in the new wire harness, all the way up to the headlight, so the new switch can plug right in.

[greasy j]

The obvious part: the OFF-LOW-HI headlight switch negates the need for the LO-HI beam one on the left side, which was how the 73-75 was wired.

The not-so-obvious part: yes, the START switch grounds to the handlebars. This was pre-'safety module', as outlined in my book: in the 73-75 harness, this means that you must connect the BLACK wire to the solenoid's GREEN-RED wire to supply Ignition power to one side of that solenoid, then you can connect the YELLOW-RED from that START button to the other side of that solenoid, and it will work fine.    And throw away the safety module...

In the 73-and-later harness, there are BLACK-WHITE and BLACK-RED and BLACK-YELLOW wires that you can now ignore, or count as spares, because they run from the K3 OFF-ON headlight switch and START button to the K3-K6 fuseblock, then back to the headlight, and to the left handlebar, which you do not need: just connect the BLACK to your new headlight switch in the headlight bucket and use a single 15 amp bladed fuse between the RED that goes to the Keyswitch and the bike's battery. (BTW: where did you get that switch? I need one for my bike, too...)

A word of caution: if you are using aftermarket (non-Honda) keyswitches, they are almost universally 8 amp switches to which someone has attached a 750 connector. These switches will melt down internally or unsolder the RED lead on the back of the switch over time, as the 750 runs about 8-9 amps all the time (Honda' switches are 15 amp type). So, install a relay somewhere, like under the seat, and use the switched BLACK wire from the keyswitch to turn on the relay coil: connect the RED to one side of the relay's NO contacts and the bike's BLACK Ignition circuit to the other. In about a week, I will be offering kits to do this, for about $25, with instructions.

I have a K1 750. I want to replace the harness or rewire because it is close to 40 yrs. old. the partsnmore harness for the 73-up is only $75. oem for my bike is $170.

if I wanted to use the 73-up harness on my 71, do I have to go through the same routine you just outlined. honestly, I had a hard time following that. I am electrically ignorant. I don't even know what a solenoid is. I googled it. still don't. could I just rig something up using parts of my old harness to make it simpler?

so far whenever I have had to wire something I have twisted the wires together and wrapped w/ tape. I never bothered checking the gauge or anything either. is there a good resource that you guys know of where I could educate myself in the basics. specific to old bikes, though. like the proper way to solder and whatnot.

and I did check the FAQ. and if you don't know, it's cool, but don't give me that google crap.

thanks!

[Toxic]

Here's the best advice you are going to get on that subject.
If your knowledge is that limited then spend the extra money on the correct harness for your bike. You can't beat "plug and play"

There are guys on here that have been playing with these old Hondas for 30 and 40 years now withour their knowledge and constant input guys like you and me would never be able to get these old Hondas up and running again.

If been playing around for 37 years with bikes but I always avoided the basket cases with wiring problems.  With my old Honda it started life as a basket case that hadn't been touched in 24 years.  There is something very satisfying when you see it start to see the bike take shape.

There are lots of resources on here that can help you if you have the patience and desire to learn.

HondaMan's website is particularly useful because you can turn off the electrical systems you are not interested in and focus on what part interests you.
http://oldmanhonda.com/MC/wiring750K1.html

Best of luck with your project.

[HondaMan]

HondaMan's website is particularly useful because you can turn off the electrical systems you are not interested in and focus on what part interests you.
http://oldmanhonda.com/MC/wiring750K1.html

That is a cool site. But, it's not mine. 
Too bad!

[greasy j]

Here's the best advice you are going to get on that subject.
If your knowledge is that limited then spend the extra money on the correct harness for your bike. You can't beat "plug and play"

There are guys on here that have been playing with these old Hondas for 30 and 40 years now withour their knowledge and constant input guys like you and me would never be able to get these old Hondas up and running again.

If been playing around for 37 years with bikes but I always avoided the basket cases with wiring problems.  With my old Honda it started life as a basket case that hadn't been touched in 24 years.  There is something very satisfying when you see it start to see the bike take shape.

There are lots of resources on here that can help you if you have the patience and desire to learn.

HondaMan's website is particularly useful because you can turn off the electrical systems you are not interested in and focus on what part interests you.
http://oldmanhonda.com/MC/wiring750K1.html

Best of luck with your project.

thanks, that is a cool link.

thing is I have been riding for about 18 yrs. every bike a cb honda until just recently, I got a cbr while I rebuild my 750. and I still haven't rebuilt an engine or rewired anything. I've cleaned lots of carbs, painted and polished lots of stuff, but old hondas don't usually need much, so I haven't had to do much else.

I am looking to fill in any of the knowledge gaps that I have. so at some point I do want to learn more about electrical matters. I may just cough up the cash and buy the wiring harness for my bike, though. in the meantime.

thanks for your input.

[matt376]

HondaMan...  Is there an easy way to see if the switch is 8 amp vs. 15amp?  I would hate to do any unnecessary work.  Also...  how's that kit coming along?

A word of caution: if you are using aftermarket (non-Honda) keyswitches, they are almost universally 8 amp switches to which someone has attached a 750 connector. These switches will melt down internally or unsolder the RED lead on the back of the switch over time, as the 750 runs about 8-9 amps all the time (Honda' switches are 15 amp type). So, install a relay somewhere, like under the seat, and use the switched BLACK wire from the keyswitch to turn on the relay coil: connect the RED to one side of the relay's NO contacts and the bike's BLACK Ignition circuit to the other. In about a week, I will be offering kits to do this, for about $25, with instructions.

[HondaMan]

HondaMan...  Is there an easy way to see if the switch is 8 amp vs. 15amp?  I would hate to do any unnecessary work.  Also...  how's that kit coming along?

A word of caution: if you are using aftermarket (non-Honda) keyswitches, they are almost universally 8 amp switches to which someone has attached a 750 connector. These switches will melt down internally or unsolder the RED lead on the back of the switch over time, as the 750 runs about 8-9 amps all the time (Honda' switches are 15 amp type). So, install a relay somewhere, like under the seat, and use the switched BLACK wire from the keyswitch to turn on the relay coil: connect the RED to one side of the relay's NO contacts and the bike's BLACK Ignition circuit to the other. In about a week, I will be offering kits to do this, for about $25, with instructions.

Matt:
Did I just send you one? I sent a kit to someone named "Matt"... 

The easiest check: see if the RED wire in the keyswitch plug is the same size as the BROWN wires. If it is, the switch is the 8 amp variety. The 12 amp ones have a thicker RED between the plug and switch. The BLACK is also thicker, but not as noticeably as the RED one.

I am attempting to make "standard" style kits now: I've been making them on a one-at-a-time basis when someone asks up 'till now. The "standard" one will mount under the seat area, near the voltage regulator.

Installation:
You clip off the BLACK wire at the keyswitch, splice it to the kit's long BLACK (I supply the splices) wire. Then you splice the kit's RED to the bike's RED near the 15 amp fuse. The short BLACK connects to the voltage regulator's terminal and joins the bike's BLACK there, and the GREEN from the kit plugs into the spare GREEN female that hangs under the seat of all the SOHC4 bikes. The relay mounts to the frame with a black Tywrap (all pieces included).