Topic: euro spec cb500 starter button help needed

[z3mcoupe]

I acquired a Euro spec CB500 mongrel complete with the Euro wiring harness.  The right hand switch controls were missing so I acquired an ebay US spec cb500 switch control.  Now I'm confused as the US spec wires are not consistent with the Euro spec.  I've got everything working so far, but the starter switch.  They both have a yellow/red wire, but the Euro requires a seperate black wire to complete the starter button circuit.  The US spec switch simply grounds the entire switch to complete the circuit.  If I attached the control switch body to a black wire, the starter button works.  The problem is that if it grounds itself (as in when it is mounted o the bar) it blows the 15amp fuse.  My question is this.  Is there a way to make this US spec starter switch work properly with a Euro spec wiring harness?  If not, does anyone have a euro spec right hand control switch for sale?  Thanks for all your help!

[TwoTired]

Do you have a pointer to the wire diagram for your euro spec wire harness?

Year/model makes a difference.  Not all the US models were wired the same or used the same controls internally.  Prior to 75 the starter switches were grounding type.  Later they switched +12v power routing to the solenoid from the bars.

Need to know how the main harness treats your solenoid connection, and what safety interlocks your bike has/needs.

One thing that could help is a wire list for your harness and the device you wish to connect, including colors (assuming they are still Honda colors).

[bryanj]

Looms are the same US to European, its the year that matters as early ones ground through the bars whilst late ones are powered via the switch(which also turns the headlamp off when starting)

[z3mcoupe]

I did a little more research.  The original wires from the missing RH control are as follows: 
Yellow/Red,
Brown/White,
Black/White,
Black/Red,
Black,
Black,
Black. 
Also, I have a 3 fuse unit block.  I believe this bike is a Euro CB500K3.  The ebay piece I bought is for a CB500K1 or K2 and has the following RH control wires:
Yellow/Red
Brown/White
Black/White
White
Blue
Black
Black

Is there a way for this K1 or K2 control to work with a K3?  I've followed the wiring diagrams and I'm 99% sure that it's a euro model.  Any help on how to make this K1 or K2 control work on a K3 is super helpful and greatly appreciated!

[HondaMan]

At the starter solenoid, connect the YELLOW-RED to a wire that will get you to the START button for grounding. Then connect the other wire of the solenoid to the BLACK wire circuit: a good place is right at the voltage regulator.

This will make the START button ground the "low" side of the starter solenoid when pressed, and if the key is ON the BLACK wire will be hot. This is how the CB350T, CB450T, CB750K0-1-2, CB500 were all wired.

[z3mcoupe]

Honda Man,

You should just change your name to "I'm da Man".  Thanks for the reply.  I connected the wires as stated and that does work, however, when the right hand control is mounted (grounded) to the bar it blows the 15amp fuse.  Any thoughts on why?

[TwoTired]

I expect by now you have realized that there were no Cb500 K3s in the US.  There were CB550 K3s and that bar control would have worked fine on your K3.

The early US Cb500s had no neutral or clutch safety interlocks for the starter motor, whereas your K3 does.

If you wish to do away with the interlocks, just connect the Yellow/red at both the starter button and the solenoid.  The G/R at the solenoid will have to be disconnected, and patched into a Black wire.  This way when the starter button provides the GND the solenoid will activate.

if you want the safety devices to function, your best bet is to get a K3 bar control, as this routes 12v instead of Gnd as the old CB500 control does...

[Don R]

You may have to use a test light in the right control to see what is hot in there that is going to ground. Is there possibly a pinched wire? Is there a ground wire on the control that could be hooked to a black hot in the headlight? There are sometimes unused wires that don't need to go anywhere. My 70 750 has a yellow and a yellow/red from the right control that go nowhere. Also a black and brown unused in the headlight bucket. A european bike should have the park light in the headlight, that is where the brown wire goes.

[HondaMan]

Honda Man,

You should just change your name to "I'm da Man".  Thanks for the reply.  I connected the wires as stated and that does work, however, when the right hand control is mounted (grounded) to the bar it blows the 15amp fuse.  Any thoughts on why?

Try unplugging the BLACK-RED wire to the right switch (if yours has one) in the headlight area. On the stock setup, this wire feeds power to the headlight through the original seesaw START switch, when the button is not pressed. If you now have the headlight switch from the earlier style, you can just connect the bike's BLACK circuit to the BLACK wire of the headlight switch, and leave the BLACK-RED loose. If you have the 3-fuse block under the seat, the BLACK-RED comes from the HEADLIGHT fuse (7 amps) back there, and could then be used as the headlight source, too. Normally, the BLACK-RED goes from the headlight area to the START switch, then back across the headlight to the HI/LO switch on the left, then to the headlight. The earlier style headlight-on-the-right switch does all the HI/LO/OFF stuff right there, instead, from the BLACK circuit.

One caveat: I have seen the BLACK-RED wire also masquerading as a BLACK-WHITE wire on some models. If you have the BLACK-YELLOW wire in the mix, that was the original START button's wire to the solenoid, so don't let that confuse you (as if I haven't enough, already...  ).

[TwoTired]

The wire diagram for the Euro K3 is printed on page 183 (chap 19 Supplement to the Honda CB 500/550 Shop manual).

Can you confirm this diagram represents the bike you are trying repair?

It shows a starter switch single pole momentary with two wires going to it.  Blk (12V power) and Y/R (power to actuate the solenoid).
 The early US CB500 represented on page 144 (chap 14) shows a single pole momentary switch with only one lead (Y/R to solenoid).  The other contact goes directly to the bar control/bars for a GND connection.  It has no other external wire for the starter switch contact.  Unless you insulate the entire bar control from the handle bar and fabricate an extra wire from the bar control body, that switch is incapable of routing 12V through it to the starter solenoid.  If that switch (early US CB500) is the only option available, I believe my earlier post is the only avenue left to utilize that switch (where you must defeat the neutral and clutch switches, by wiring them out of circuit).

This post is based on the assumption that the two diagrams referenced represent what the OP has in hand and is trying to marry.
However, I do note that none of the K3 wire diagrams shows a Br/W wire going to the R/H bar control.
The color codes for Honda were  (from your list):
Yellow/Red - Starter solenoid  (switched from a Black wire)
Brown/White - General lighting (like instrument bulbs)
Black/White - Coil power
Black/Red - Headlight power  (to fuse block)
Black  - 12v From Key switch
Black  - 12v From Key switch
Black  - 12v From Key switch 

The CB500 K1 wires at bar control are:
Yellow/Red - Starter solenoid (switched from GND)
Brown/White - General lighting
Black/White  - Coil power
White - Headlight low beam
Blue - Headlight high beam
Black - 12v From Key switch
Black - 12v From Key switch

The K3 should have the Headlight H/L switch on the left side of the bars, not like the K1, which has it on the right side.

[z3mcoupe]

TwoTired, you are a terrific help! My bike was exported to Germany, then France, then USA and I think I speak for most of the US biker nuts here that anytime we have something from overseas it's automatically waaaayyy cool.  I disconnected the G/R wire at the solenoid and tapped into a black wire.  It works like a charm.  It works so good, it even works when the run switch is in the OFF position!  No problem as long as I stay away from the starter button while riding I'm good.

The switch is a single pole with Y/R from the switch control being connected to the starter relay and grounded through the switch to complete the circuit.  Also, I do have that unique (here anyway) left control with the Hi-Lo switch.  Now I have it on the right too since finding a RH switch for a CB500K3 over here will be impossible.

Thanks everyone for all your help!

George

[TwoTired]

It works so good, it even works when the run switch is in the OFF position! 

That pretty normal, George.  The Stop Run Stop switch controls power to the coils, or whether the engine is capable of running.  Really not much to do with the starter circuit.

What you have to be careful with, is leaving the engine in gear with the clutch out.  The 500K1/K2 control had no interlock capability.  If, for example you left the bike in gear on the sidestand, the starter motor will make the bike lurch forward, possibly knocking it off the stand.
In 74, they began making interlocks to prevent that (starter motor safety unit).  By the K3 version, the bar control had changed to route power instead of gnd to the solenoid, so the neutral switch and the clutch switch could be utilized as the safety unit(s).  So, as I mentioned earlier, the mod wiring I recommended to get you going reverts the the safety features of the 500K1/K2 model (none).

The H/L headlight selector switch is common on the K3 550 (all F models, too.)

I really think you would be better off getting a CB550 K3 right bar control.  Then you could re-enable the neutral and clutch safety devices.
But, it's your bike and you should do what pleases you.

Cheers,