77 78 wiring harness confusion

[Michael Shane]

I'm new to forum and thanks for having me. I'm rewiring a 77 gs750 that the previous owner caught on fire when a fuel leak ignited. I ordered a used oem 78 harness. My bike has a dark blue wire coming out of transmission. The 78 harness has no dark blue wire. This wire is for neutral safety light. The gauge cluster has the blue wire attached to the connector. Am I missing a separate harness? Did Suzuki separate blue wire from main harness from 77 to 78?

[Redman]

Welcome to TheGSR.

I have hands-on familiarity with only 1980s Gs, so I cant answer specifically about the darkblue wire on your 77 750.
But I can say the neutral sensor is used only to light a light - only. Not in interlock to starting or the ignition.

You have any schematics to follow? Have you found BassCliff site?

[Michael Shane]

Welcome to TheGSR.

I have hands-on familiarity with only 1980s Gs, so I cant answer specifically about the darkblue wire.
But I can say the neutral sensor is used only to light a light - only. Not in interlock to starting or the ignition.

You have any scheamtics to follow? Have you found BassCliff site?

Thank you. I'm glad to be here. I do have a manual with colored wiring diagrams. If there is a 2nd harness just for gear selector wiring then I would like to find it. And I have found BassCliff, tons of info!

[allojohn]

The part numbers for the ‘77 and ‘78 harnesses are different so they are different in some way. There is a six wire
separate harness with the gear indicator module on one end and plug on the other.
HTH

[Michael Shane]

The part numbers for the ‘77 and ‘78 harnesses are different so they are different in some way. There is a six wire
separate harness with the gear indicator module on one end and plug on the other.
HTH

Thanks for reply. Do u have part number for it? Or the official Suzuki name for it? I looked on EBay and couldn't find it for sale. I bet a Suzuki dealer could look it up though.

[Redman]

. . . . . .. . . . I do have a manual with colored wiring diagrams. If there is a 2nd harness just for gear selector wiring then I would like to find it. . . . . . . . . . . .

WHen you say "a manual with color wiring diagram", that makes me suspect you mean Clymers manaul. On those manuals, of the Gs, there are errors in the area of the ignition switch (mostly the function chart off to the side).

Again, I dont know about the 77 78 750s, but on models I do know (80s G), that have the gear selection lights, there is a rotary switch down on side of xmision that has a 6 conductor connector/harness (for gear 1-6 even if only 5 gears/lights) (that is separate from the main bike harness) AND a single separate wire/connector for neutral (that does go thru the main bike harness).

[allojohn]

Can't find a part number but the part looks a lot like this.