Author Topic: early wire harness...newer bike  (Read 6385 times)

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Offline HondaMan

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Re: early wire harness...newer bike
« Reply #25 on: July 08, 2011, 09:00:55 PM »
well....it didnt work..im not getting any spark..i didnt use and jumpers.i just cut the wires and solderd them..can anyone see from the pics what i did wrong?







In the 4th picture (of the coils), the Green ground wire appears to be loose. This MUST be grounded to the frame, right there on the front left side coil mount. Make sure the frame is cleaned of rust and paint where the bolt for the left coil mount goes in, and mount the Green wire against the frame, trapped under this bolt and mount.

Back under the seat area, the Green wire (with a similar ring terminal on it) may also be there, since the wire harness is a collection of 2 different years. If so, connect it to the threaded hole underneath the seat latch bracket. Having 2 grounds won't hurt anything.

The fuseblock: those wire colors, if they are showing accurately in the photos, look like a non-Honda color code? There should be 2 RED wires to the 15 amp MAIN fuse, two BLACK-and-RED (or might be BLACK-and-[something else stripe]) to the 7.5 amp fuse, and BROWN and/or BROWN-WHITE to the 5 amp fuse. The colors from the wiring harness will match the RED for RED, the BROWN(s) for BROWNS, and the remaining 2 will be for the 7.5 amp headlight fuse, whatever BLACK-and-[something] that they are.

Make sure also that your BLACK wire in the headlight is connecting to the BLACK-WHITE wire in there by way of the RUN-OFF switch: jumper it manually if you have to for now. The BLACK-WHITE feeds power to the coils from the RUN-OFF switch on the right handlebar. The BLACK wire feeds that switch. So, jumpering past the switch for now, in the headlight, will at least get power to the coils for sure.
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Offline immortal

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Re: early wire harness...newer bike
« Reply #26 on: July 27, 2011, 11:13:55 AM »
Hi Pat, Did you figure out what to do with the 2 prong plug next to the Solenoid with the Red wires. I have the same thing on my 1976 750F harness and trying to figure out what to do with them? Also I have another little 2 prong plug with what looks like a little relay plugged in too, Dont know if you have that one.
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Offline Patrick

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Re: early wire harness...newer bike
« Reply #27 on: July 27, 2011, 11:35:28 AM »
That little relay is a diode. It is part of the safety system in the later bikes, replacing the red safety unit that connects to the red connector in a '75. I actually have been working the opposite problem - making a 1978F wire harness work on my '75 750. Too bad I didn't see this post before we both started modifying the harnesses.

Patrick
1970 CB750 K0
1982 VF750S Sabre
1987 VT1100 Shadow
1979 Yamaha XS11
1969 Yamaha DT1B
etc.