Ok so now I know vintage connection carries replacement round plugs. Thank you Don R.
Does anyone know where to get new rubber parts that cover the plug and ignition?
Sometimes PartsNmore has the one at the switch end. I haven't seen the round-plug end, though.
A question: are you 'set' on using the round plug? If so, get NEW contacts for it, and for the wire harness side, as they were not rated high enough in current, and for this reason Honda ended up switching to the blade-style plug in the K3 (and some late K2 as well, from the New Factory). This was a chronic electrical 'bug' in the early 750, causing low voltage all thru the system. It was for that reason that I first created the "Keyswitch Saver" relay kit for those who want to stay with that plug, but would like a little better electrics, too.
My K2 was one of the very first of its kind and has many K1 leftovers for that reason. After burning out several of the round plugs over the years, I swapped the harness end to the rectangular one and now use the K4-K6 keyswitch. DON'T use the EMGO (non-Honda) versions of these 2 switches: EMGO is using the CB350 8-amp keyswitch with the 750's plugs added, and they last about 2 months of commuting. I went thru 3 before I figured this out, years ago, and bought a Honda original (K4) version, then added the relay, too. Stopped all the troubles... 
I was about to start a new thread and hoped you'd chim in. I recently acquired a few parts, including an ignition switch, wire harness, etc. Im also in the process of organizing everything that I have for my 750.
I remember reading about 9 years ago that the Emgo switches are not good after mine melted my plug and wire harness. You are correct, lasted about 2 months of commuting. I then replaced the contacts of the plug, bought a honda switch, and it never happened again.
I found it odd tonight while going through the "new" parts I initially couldnt get the OEM ignition plug separated from the wire harness. That's because it had melted. I immediately thought of the EMGO switch. In the photo is the EMGO on the right, OEM on the left.
I am interested in keeping the original round plug. I have an ignition switch that matches my seat and fork lock. If possible Id like to keep as much original as possible.
That brings the next round of questions. If I add the "Keyswitch Saver" relay kit, would I have to change out the contacts for the round plug?
Final question, if I were to change out the ignition plug to the blade style rectangular plug, what year wire harness best fits an early K2 and who is a good manufacture of wire harnesses?
Thanks again.
