Looking at the main rear portion of the harness of the GT750 I wanted to fix some issues with its design so here's how I tackled the update to this part.
First I stripped all the old insulation tape off and separated the wires down to their respective coloured circuits. Then I set about cleaning all the wires, terminals, silicone boots and checked and re-wrapped the taped splices.
Looking at this, its easy to see why theres some voltage drop in the charging circuit and coil circuit, so heres what I did.
First the red wire, it goes from the mid connector between the two harnesses to about midway back and is then spliced at the turn of wire there to the fuse then continues to the rectifier socket.
I took this wire out and upsized it to 12 gauge wire following the wiring pattern off the old one, but I used a crimp at the splice and then soldered it covered by heat shrink tubing.
For this sort of splice you don't have to cut both wires, just bare a section about 1/2 inch long and lay the second splice into the area between the sheathing, crimp and solder it, then insulate the joint.
More power in from the battery with less resistance equals one problem solved, now we can use a 25 or 30 amp main fuse.
From the harness mid joint the red 12 gauge wire will continue up to the ignition switch where at its connection it will get a large four pin style socket to reduce any resistance issues.
Next was the orange wires, here I did some modifications to how it was from stock.
Removing the original one from the mid harness joint, I used a piece of orange 12 gauge wire and ran it from the mid harness socket location right to the regulator connector. Then I removed the original short run splice of the three orange coil wires from the old orange harness wires and spliced them into this 12 gauge orange wire.
I reused the original three small wires, but their run is now very short from the 12 gauge feed wire splice so thats ok.
This means power from the ignition switch going to the regulator and ignition coils will be on a large 12gauge main wire only.
I also removed the other medium sized orange wire from the nine cavity socket and made it a separate circuit running the flasher and rear brake lamp circuit and fan relay (if fitted).
This second orange wire is now fitted into the mid harness connector so it can use a larger pin terminal. It will run up to the front of the headlamp harness on a 12 gauge wire which will splice into the other orange wires there now.
The end result will be a branch of two 12 gauge orange wires from the new ignition switch connector. One will run into the front harness then into the rear harness and one directly into the rear harness for the coils and regulator.
Suzuki placed too much emphasis on the orange wire as a common12 volt feed tap and sadly the ignition switch does not have a dual terminal in it to use a parallel output for two separate orange wire feeds.
The original black and white wires from the mid socket are ok in gauge size so they were left as is, but their connector end by the mid socket was changed to the large pin so it can also work in the update.
All the other wires in the nine cavity socket were removed and cleaned up and put back as they were, but since it was not a latch socket, it was upgraded to one.
The yellow short run of three wires from the rectifier socket to the alternator socket will be upsized, as will the green short run from that socket to the regulator.
This covers the basic rear harness updates and here are some photos, its been laid out and sectionally taped for now, the rear portion by the short wiring for the regulator and rectifier is not completed yet in this photo.
The updated rear harness laid out and sectionally taped.
The original wires were cleaned up for the electrical panel area, the new 12 gauge red one for the fuse looks massive in comparison.
The black nine cavity latched connector replaces the old stock one.
The coil wires also got a new six cavity latched one (partially hidden)
The large four pin connector is the new mid harness socket, one red, one black/white and two orange wires now fill its cavities.
Now to finish this part up and see about working on the front harness.
