Topic: Mini Gauge Wiring Help CB550

[jeffcampagna]

Hey everyone. Love my original 77' CB550K but the time has come to make some small mods to it.

I've got a Mini Tach and Speedo and I've got the majority of the wiring all hooked up based mostly on this awesome SOHC topic: http://forums.sohc4.net/index.php?topic=147394.0

But... I've got two rogue Harness wires that have nowhere to go (Blue, Brown/Blue). Looking for some guidance on what the hell to do with them.

How I've got everything connected so far:

Tach
Black connected to Green (Harness)
Red connected to Black (Harness)

Speedo
Red/Black connected to Blue/Red (Harness, oil)
Red wire and Green wire connected to Brown/White (Harness)
Yellow/Black, Black, Blue/Black all connected with one connector to Green (Harness, ground)
Orange connected to Brown/White (Harness)
Blue connected to Blue (Headlight)
Green/Black connected to Green/Red
Yellow connected to signals with a diode.

Some pics attached.

Thanks in advance for the help guys. (I ******* hate wiring ;)

[DaveBarbier]

Do you have a wiring diagram?

The brown/blue is for the winker buzzer. If you're not using that then you can tape it off or remove the wire completely. Or, I saw a post where a member hooked up the brown/blue to the gauge's signal indicator, which was pretty smart. That way you won't need to do the ol' 2 diode trick. You only mention 1 in your post. You'll need 2 for it to work properly. One on each signal wire from the harness going into the gauge's indicator (orientation matters with diodes)

The solid blue wire is for high beam. I see in the double terminal for the blue wire going to your H4 headlight plug you only have the high beam indicator wire for the gauge plugged in. You need power to illuminate the high beam from your loose blue wire.

You going to shrink all those heatshrinks?

[jeffcampagna]

Hey Dave,

Yeah, I've got a CB550 wiring diagram and it's helped a bit, but it's a bit convoluted for my novice eyes.

So, I taped off the Blue/Brown like you said. And I've got the Blue wire running into the headlamp connector (see new pic).

Everything seems to be working (bike turns over, lights work etc...) EXCEPT all four of my signals stay on all the time. If I activate a signal, there's a brief moment where it turns off, then turns back on without a flash. Is this due to the fact that I only have one signal diode? The guy I bought the gauges off of only sent me the one!

And yes, haha, I'm going to shrink the heat shrinks. I just know that I've probably made a few mistakes and didn't want to the heat gun before the horse....

Thanks for the help, sir.

[calj737]

Yes.

[DaveBarbier]

You'll need two diodes like I mentioned above, I use 1N4001 diodes but others could work. If you have a Radio Shack near by (not sure what they have in Toronto) they'll have them for like $1 each which is actually a little expensive. Or you can use eBay or Mouser.com

If you search the site, or search google with "sohc4" in front of your search you'll come up with many posts with explanations and diagrams on how to wire it up.

If this is the only issue you've got when wiring up these gauges then I'd say you're doing pretty good for a novice

[jeffcampagna]

Hey Dave,

So, do I need two more diodes for the rear signals as well, then?

I've rebuilt a few bikes in the past, but I've never really messed with wiring. I guess I'm somewhere in limbo between novice and amateur.

Nice 550K by the way. It's one year older then mine. Great bikes. Will post a pic once I'm done with her. Won't be long now. I'm keeping her pretty close to stock, just minor changes.

[calj737]

You only 2 diodes period. They go onto the input wire for the gauge, separating R and L side indicator power flow from each other.

OR, use your stock R turn signal tap wired to the gauge, and use BROWN/BLUE you taped off for the L side. Skip the diodes completely.

The front and rear indicators are powered from the same circuit so don't confuse yourself about each side and both ends being signal generators to the gauge.

[jeffcampagna]

Hey guys,

So I tried removing the single diode and wired the Brown/Blue buzzer wire to the Left Signal in the Harness, and the Yellow wire from the gauge to the Right Signal in the Harness but it didn't help. Then I put the diode back in, and same issue. Lights just stay on. Unless I turn a signal on, then the signal I turned on goes off completely.

Any idea where the electrical gremlin could be lurking? Is it safe to assume the bugger is hiding in the harness' signal ports? Cause everything else seems to be working fine. Could it be anywhere? arg....

Thanks for the help guys.

[calj737]

You don't wire the Br/BL to anything but the gauge input, where you have the right side wired. You leave the right side connected to the gauge as is, without the diode. Because the Br/BL is NOT connected to the actual indicator light, it won't bleed over when the right side is active.

[jeffcampagna]

Gotcha. Will try that out ASAP. Thanks!

[jeffcampagna]

Hey Gents,

So, Signals are working finally. Thanks for all the help. Think I had the leads going into the single harness connector mixed up with the leads going into the double harness connectors.

But.... now that I hooked by headlight back up, both the headlight and the hi beam work well, but the hi beam indicator light in the mini speedo seems to be opposite. When the hi beam is activated, the light goes off, when the hi beam in turned off, the light comes on.

Any ideas? I tried a few different combos (swapped the blue and the white, but that killed the hi beam entirely.)

Thanks guys.

[calj737]

The wire that feeds the gauge comes from the BLUE wire that feeds the HI beam. Whatever color your HI beam uses, splice into it and attach it to the gauge input wire.