I hope this ain't too wordy...
My philosophy's kinda always been throw money at tools and consumable bits (and do a bunch of reading) rather than hard parts, especially when then option is to have tools and materials for the next project costs roughly the same or slightly more than throwing money at a questionable aftermarket product. Unsure if OEM is available from Honda. I just checked a site I use from time to time that provides decent, aftermarket stuff for our bikes. They sell harnesses for 69-71 and 73-75 for $72 right now. The rub: K0, K1, K2, K3&4 (maybe the same?), and K5 all have differences, so none are really plug and play without some head scratching (What DOES this brown/blue wire supposed to do??? Why does this green/red land here???, etc.).
Here's my bit: inspect all yr connectors. Clean female bullets with q-tips and something like Caig Detoxit D-5. Scuff males with fine-ish (220-300) sandpaper. Use tiny flathead to remove blade connections from blocks (mark the block for color, R, G, Y, etc). Carefully untape the whole harness. Take note and mark where sub-harnesses- dunno a better term... like, say, the wiring for the ignition switch- branch out. Look for those wires that melted together over the years. This is also the time to lose extraneous stuff like the neutral lock out wiring (and all the BS "repairs/mods" that the past 4 PO's did), if you so choose. Solder in wires to replace grilled cheese bits (check heat sink photo) and leave slack to measure to already mounted parts if new connectors are required. All the soldered connections I've seen left the factory with brown tape. Don't worry about heat shrink.
Check out vintageconnections.com . Del pretty much rules the world of quality electrical minutia for the machines we dig. Get 3.5 mm bullets to connect to stock harness, a crimp tool, whatever blocks that need replacing, and a roll of Scotch 33+ tape from him. A 30-45w soldering iron, a small roll of rosin core solder, and a couple of alligator clips and you're on yr way to rehabbing a better harness than aftermarket might provide.
