Topic: yellow and red wire, top of solenoid

[Green74cb750]

should it read any voltage, I'm getting zero?  Also the black wire next to it is dead... 

[KingCustomCycles.com]

Red yellow will show voltage with the key on and the start button depressed.  Black wire is ground.

[bollingball]

Looks like R/Y gets hot from start button. Key sw, on. I don't know if 74 had the ssm if so the bike has to be in neutreal or clutch pulled in.

[TwoTired]

Honda convention: black wires are switched 12 V  (It's in the FAQ, as well)
For your particular model (74CB750), the black wire is hot when the key is on.
The Yellow/Red supplies gnd or Battery NEG when the button is pushed.

Cheers,

[KingCustomCycles.com]

In my defense TT, those wires can be crossed and still function I believe?  I'll go away now..........

[Green74cb750]

Thanks.  So, I'm getting a zero read with key on, clutch is not pull in.  This bike is a new project and I've never started it...not sure how, do i need to pull the clutch lever in to test the yellow/red wire and black wires?  Will the ground wires give me a 12v read if working properly?

[Green74cb750]

And what is this about the wires being switched?  (too tired and customkingcycles)

[bollingball]

TT will know for sure But I don't think a true grd (green) will not, no

[Green74cb750]

Also, I just have wires hanging on the right hand switch--NO BUTTONS, could this be why I dont have a read on the red/yellow?  Anyone bought start buttons, I read somewhere in here about a button at radio shack?

[KingCustomCycles.com]

When you touch those wires sticking out where the start button used to be, it should crank.  I have seen that "fix" many times.

[bollingball]

Green I did buy a button about a year ago I will dig through my papers I think it was from DSS.

[Green74cb750]

Green I did buy a button about a year ago I will dig through my papers I think it was from DSS.

Thank you!

[Green74cb750]

When you touch those wires sticking out where the start button used to be, it should crank.  I have seen that "fix" many times.

I'll give it a go and report back, thanks

[TwoTired]

The solenoid will activate when power is applied across the Black and Yel/red wires.  It doesn't matter the polarity if they aren't attached to the bike harness.  These leads attach to a coil of wire inside the solenoid.

A voltmeter measures a potential across the leads/probes.    With probes unattached the meter should read zero.  If you put just one probe on a battery terminal, the meter still reads zero.  When you place probes on both battery terminals, THEN you get a meter reading.

The same is true wherever you probe with the meter, and you must state where BOTH probes are connected for any reading you give us to be meaningful.

If you don't have switches on the bike, how do you expect the thing to work? 

Anyway, if you want the solenoid to activate.  The key switch, if you have one, should supply 12V to the black wire of the solenoid, assuming it is connected.  If you just want to test the solenoid, (you never told us what your goal is).  Then jumper the battery neg terminal to the yel/red wire on the solenoid, (disconnected from the wire harness).

If your goal is to see voltage on the yel/red wire, then supply 12V to the black wire of the solenoid, and place you meter probe on the yel/red and Battery neg terminals.  The solenoid's internal coil will distribute the voltage through it, so you can see a satisfying reading.  Normally, it will read 12V until you ground it out, (which will activate the solenoid).

[bollingball]

This is where I got my horn button had to modify with dremel just a little but worked fine

http://www.cb750supply.com/products/5/electrical/56/horns

[Green74cb750]

The solenoid will activate when power is applied across the Black and Yel/red wires.  It doesn't matter the polarity if they aren't attached to the bike harness.  These leads attach to a coil of wire inside the solenoid.

A voltmeter measures a potential across the leads/probes.    With probes unattached the meter should read zero.  If you put just one probe on a battery terminal, the meter still reads zero.  When you place probes on both battery terminals, THEN you get a meter reading.

The same is true wherever you probe with the meter, and you must state where BOTH probes are connected for any reading you give us to be meaningful.

If you don't have switches on the bike, how do you expect the thing to work? 

Anyway, if you want the solenoid to activate.  The key switch, if you have one, should supply 12V to the black wire of the solenoid, assuming it is connected.  If you just want to test the solenoid, (you never told us what your goal is).  Then jumper the battery neg terminal to the yel/red wire on the solenoid, (disconnected from the wire harness).

If your goal is to see voltage on the yel/red wire, then supply 12V to the black wire of the solenoid, and place you meter probe on the yel/red and Battery neg terminals.  The solenoid's internal coil will distribute the voltage through it, so you can see a satisfying reading.  Normally, it will read 12V until you ground it out, (which will activate the solenoid).

Okay, my goal is find where my electrical problems are, and to learn how to get the electric system to work.  You guys have answered my question about the yellow/red and black wires.  To start it I'm going to need to wire up a start button.  this is what i'm working with

[Green74cb750]

here we go.  the black has been soldered to a black/white (was taped)  there's a green and a yellow/red, then a brown and ahh...refer to photo

which of thes should be attached to start button?

[TwoTired]

Electricity doesn't much care about wire insulation color.  Those colors are for humans, which helps sort out what is going on and what's connected where.
In the FAQ, you can find a write up showing guidelines of what Honda used for what purpose.
Black/White is generally power for the coils, and the stop/run switch will cut that power off to stop the engine.

If you aren't going to follow Honda convention, telling us the wire color you are using won't help, unless you follow it back to it's source and tell us what connects to it at the opposite end.

Is your start button a Honda unit that matches the year model of your bike?  Are you using the stock wire harness for your year and model bike?

I suppose it sounds like I'm being a hard ass.  But, electricity doesn't work for you on good intentions alone.  It has very specific needs to operate, and you either supply those needs, or you simply don't enable what you want it to do.

Do you have the stock wire diagram for your bike?  That is your road map for the electrical pathways.  It's rather hard to navigate the unknown without a map.

[Spanner 1]

The green and yellow/red go to the start button..........
For the solenoid to 'click' and send energy to the starter motor, the appropriate wires must be connected in the h/l bucket, the ign. 'on', the bike must be in N ( or the clutch pulled ) and you must have 12+ volts at the black wire @ the solenoid..........

[skamagedon]

take a screwdriver to the 2 posts on the solenoid and it should crank if the starter is good. any black reading 12v can be jumped to the yellow/red and should get the same result.

[Green74cb750]

Electricity doesn't much care about wire insulation color.  Those colors are for humans, which helps sort out what is going on and what's connected where.
In the FAQ, you can find a write up showing guidelines of what Honda used for what purpose.
Black/White is generally power for the coils, and the stop/run switch will cut that power off to stop the engine.

If you aren't going to follow Honda convention, telling us the wire color you are using won't help, unless you follow it back to it's source and tell us what connects to it at the opposite end.

Is your start button a Honda unit that matches the year model of your bike?  Are you using the stock wire harness for your year and model bike?

I suppose it sounds like I'm being a hard ass.  But, electricity doesn't work for you on good intentions alone.  It has very specific needs to operate, and you either supply those needs, or you simply don't enable what you want it to do.

Do you have the stock wire diagram for your bike?  That is your road map for the electrical pathways.  It's rather hard to navigate the unknown without a map.

Thanks for the enlightening post.  yes, the harness is the same for the year of my bike--the 73-75 one.  I wouldn't be asking these specific questions about color if I weren't using a stock harness.  Yes, i know that electricity doesn't much care what color the wire insulation color is.  You are kind of being an ass, yes.  if you are going to talk down to me every time you post, just don't. yes i have the diagram.  I have zero switches on right hand, only wires with color codes.  As i only have a limited knowledge of bike electric/mechanics I am asking some questions to get some help.

[TwoTired]

Ok.

Good luck to you then.

[bollingball]

Green I know it can get frustrating some times. The heat makes me grumpy Don't burn a bridge that you may need to go over again one day
Did you get it to work yet?

[skamagedon]

the start switch also has a kill for the headlight. like  the hi low beam switch. black in hot. yellow red to soleniod, black red to headlight

[Bodi]

early bikes don't have the headlight kill switch IIRC. I don't have a full set of wiring diagrams so I can't speak with certainty about your bike.
If you have one of the various color wiring diagrams, shred it and start over with a real Honda wiring diagram. These were in the owner's booklet and service manual, and should be findable on the web. get the right version - at least the right year if you can as the differences between a K and F aren't serious.
Look for obvious oddities in your harness. Taped or soldered wires, melted wires, extra wires added to the outside of the harness tape... whatever. Try to sort these out first.
There are single fuse and three fuse versions of the harness, three fuse started around 1973 I think. Regardless, with good fuses you should have battery +12V on every black wire in the harness when the key switch is "ON". If not, find out why.
The starter circuit changed a lot over the years. I think they all had some sort of starter safety system preventing the starter motor from working with the trans in gear and the clutch engaged, maybe very early models didn't. This circuit changed a bit - some have a solenoid with +12 on it all the time and the ground is switched (via the start button) through a safety unit, some have the solenoid grounded and the start button switching +12 coming from a diode from the neutral switch or from the clutch lever switch. The color diagrams generally skip these (and other...) details: these are rather vital to debugging the starting circuit.
TT knows what he's talking about, after a few years of helping us he has limited tolerance for dumb questions. Asking about the starting circuit then later mentioning the switchpod is not connected is a bit naff. BTW, hopefully you have the original switchpod. Although many look the same, the switch wiring and wires coming out are very different for different years and bike models.