Author Topic: More help w 550k munit wiring  (Read 2026 times)

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Offline Misanthropist

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More help w 550k munit wiring
« on: September 18, 2024, 04:37:42 AM »
Hey all, posted a couple weeks ago and got my problem worked out. Now a new issue. This thing is kicking my butt. 78 cb550. Everything works right except the start/ignition circuit. 

Coming from the R handlebar (start and killswitch), I have 2 black wires, 1 black w white, 1 black w red and 1 y w red.

Currently I have the b w w going to the coils. The y w r going to start input and the b w r going to ignition output.

If I put the 2 black to ground, the starter circuit works. If I put them to 12v the ignition works.


Offline Misanthropist

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Re: More help w 550k munit wiring
« Reply #1 on: September 18, 2024, 06:47:06 AM »
What actual RH switch control are you using? Stock? Aftermarket?

How you should wire the sequence up is from mUnit switched power side:
AUX - BLKWHT to coils.
START - To solenoid YR

From RH control to mUnit input side:
YR to START
REDBLK to KILL

One of your wires at the control needs to be grounded to the frame so that ALL wires in the control send a ground signal to the mUnit. The above assumes the YR and RB connect within the control. You can use an Ohm meter to test that by checking continuity with  the RUN switch. But if your control is not stock, colors may be off.

Thanks, yes stock controls. 2 black and b w r have constant continuity. I have continuity on the kill switch when on with 2 black + b w w OR 2 black 1 b w r. For start, I have continuity with 2 black and 1 y w r (when pressed). None have constant continuity w ground

Offline Misanthropist

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Re: More help w 550k munit wiring
« Reply #2 on: September 18, 2024, 11:45:44 AM »
They won’t have continuity to ground until you wire one of them to ground. You are “re-routing” the circuit so that when pressed, the button sends a ground signal to mUnit. Stock configuration had them pass voltage. You are changing that. The power goes from mUnit directly to the component, the switch sends a ground signal to mUnit.

Should I put the blk wht directly to coils from aux and bypass the switch?

Offline Misanthropist

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Re: More help w 550k munit wiring
« Reply #3 on: September 18, 2024, 02:16:09 PM »
Clear. I'm gonna wire 2 black to ground and everything else you said. Only minor inconvenience is its going to run in the kill position and die in the run position (3 position kill/run/kill switch) No big deal to me