Topic: Wiring Purpose built Moto black box to stock harness-cb750 help!

[Bduck72750k]

I dont usually post but wondering if anyone has used a Purpose Built Moto black box V3 woth their 2 or 3-button switches. I have a stock harness (brand new) for my CB750k4, and i have a wired in LED tail light (integrated with signals) and LED headlight with integrated signals.

Trying to make sense of the k1 k2 wires in the diagram and whether an additional relay is needed. This is not currently on the bike as im awaiting all my rts to come back from powder coat. I guess im hoping to find someone who has done this that can help me along. Also curious what they are referring to when commenting “+ve”. Thanks!

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[calj737]

That Black Box looks very much like a cheap clone of a MotoGadget mUnit.

Using momentary switches, you might as well ditch your new, stock harness. The wires from the push buttons are "grounds" and trigger the input side of the Black Box to send power to the output side (+VE or switched 12v) and directly to the component (lights, indicators, tail light, etc). You'll be hacking up the harness a fair bit because it was originally configured to route power through the switch at the handlebar, then onward to the component.

One of your links (Black Box sw diagram) is zero bytes, so can't open it to examine it.

Looks like the k1, k2 wiring is for powering the coils/ignition. Likely routed to a KILL/RUN switch. Normally closed, it would pass +VE through it (RUN), OPEN it severs the power (KILL)

[Bduck72750k]

Hopefully that uploads now-

Thank you for the reply! At this point im invested into this unit unfortunately so ill try and make it work. This is my first build, so learning from mistakes. My hope is to get this working and maybe i will in the near future convert to an M-unit. My goal was to clean up the front end with new switches.

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[calj737]

Run wires from the black box to a relay, using k1 and k2. That’s what the diagram shows. That relay sits between the push button and the black box. When closed (RUN) it sends power to the coils. When open (KILL) it disrupts the power to the coils so the bike won’t start/fire.