NC23 Indicator Strangeness

[AdrenalineJunky]

This is a bit weird. I have an NC23 Aero here and when indicating left, both left and right indicators come on and flash, at the front and at the back. It works fine when indicating right though. In the opinion of the knowledgable gentlemen posting here, is this likely to be a fault with the switch or something more time-consuming to do with the way it's wired up? I imagine this bike has a non-standard loom since it's been streetfightered bythe guy I bought it off - I've already discovered that he hasn't wired up the neutral light at all, and had to replace a too-long clutch cable that had been "imaginatively" routed so it was being trapped between the frame and the engine...

Any and all advice, torubleshooting plans, wiring diagrams, etc, gratefully received! I have the wiring diagram from the CBR400RR NC23-J that superseded the Aero in '86, does anyone know if the wiring is identical?

[AdrenalineJunky]

I think I have figured out what is happening....

The dashboard warning light that flashes when your indicators are on is connected to the "live" side of both the left- and right-hand side indicator circuits (see wiring diagrams in Haynes manual). So there are supposed to be diodes on either side of the dashboard turn-signal warning light to prevent any current from going "the wrong way" and lighting the bulbs on both sides of the bike. I emailed the guy who'd built the bike and he said this too.

I have simulated the circuit using the Java circuit simulator applet here: http://www.falstad.com/circuit/

If you want to see how it works, and play with the circuit, this link will open the applet with my "Turn Signal Simulator" running: http://www.falstad.com/circuit/#%24+1+5 ... tor+mk1%0A

GODDAMN THAT'S A BIG LINK! But pretty cool if I say so myself. By opening/closing the switch marked "short?" you can see what happens if the diode fails to block current on one side of the warning light - both sets of bulbs (left and right) come on. The circuit uses a DC source unlike the real one obviously but the current paths are unaffected by this so it is the same as what is really happening except the bulbs don't blink, they just light up. There are relays in the applet's toolbox but I couldn't be bothered with it, since the principle is the same. The dashboard warning light had to be made of two LEDs because the applet doesn't allow for a non-polarised LED to be used. If you open the switches next to the 992 Ohm resistors then turn off the indicators (switch marked "on/off") then some parts of the circuit remain at +6V above ground. The reason I put those switches in was to see the effect of what would happen if there were no high-resistance resistors there.

I hope this circuit is of use to someone, some day! I couldn't find a decent answer to this problem by googling so maybe this will help somebody in a similar situation one day. Of course, I haven't actually proved this is the case in reality yet, that will have to wait until I have time to look at the bike and solder in a couple of diodes after the dashboard light.... But I am quite confident that this will solve the problem, since this is the only way I can imagine the problem arose in the first place... I'll post back here after making the repairs.... FINGERS CROSSED!

[leopard_pagan]

"o there are supposed to be diodes on either side of the dashboard turn-signal warning light"
>> nope, this is a modification. not standard at all..

one i need to finish on my bike in fact!

in the link is a diagram on how the indicator diodes go

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