So true. I'm up to seven now and though I say I'm going to cull the herd they just seem to always be one nut away from being finished. (guess who the nut is). 

It seems much easier to find the parts you need when you need so many parts. 

That's hilarious! I've had so many classic cars over our 40 years of marriage you think she would be used to it by now. At least I can still park my truck in the garage with motorcycles.

Hey I'm working on this bike again and was hoping you could get me some additional pictures. I'm looking for where all wires go that are associated with the battery,  including the fuse cable. If you can get some additional pics I would greatly appreciate it!

Hello there..... I have the same bike . I need the same answers ! Where second lead off of positive of battery goes, Where other red wires go and hook to voltage regulator . 

I haven't had time to work on my bike much, but I'm hoping to turn that around and get it running before the weather makes it a next year project... If I make any headway I will post it here.

Thank You. I can`t believe no one with a Electric start bike can`t supply all red wire connections under seat!

Here is AT2 large gauge goes to the battery so here’s a picture of the fuse etc hope this helps 

Cannot tell which ones heavier? Fused one comes from battery? Or the top one? You  have heavy wire going to starter relay and pigtail going to ? Maybe draw a diagram or show positive on battery and where they go? 

As I may have posted earlier, the RD200 is similar (but not the same) set up, so this might help:-

The terminal with the two wires exiting it attaches to the regulator. The heavy duty wire with the ring terminal goes to the battery. The wire with the female bullet connector attaches to one of the males from the fuse holder.

The single wire (ie not in the block) coming from the regulator, with the male bullet connector, connects to the female coming out of the end of the main harness under the seat (on the RD200 this has two wires going into the single female bullet connector).

The other male coming out of the fuse holder attaches to a single female coming out of the main harness a few inches from the end.

I've attached a photo of mine loosely connected (edit can't post photo).

There is a service manual in the Tech Library that covers the 100, 125 and 175 bikes (see link) and at the back of this is a routing diagram for a the 1976 DT125C - hopefully there wasn't much change between 1974 and 1976. If the main harness is routed correctly, then a lot of the connections become more obvious (ie you shouldn't have to stretch any wires to connect them).

Finally, I've sometimes found it useful to try and find photos of original, correct parts, just to make sure that a wrong part hasn't been fitted to one of my resto projects. I've found CMSNL a very useful source of photos. 

Even if your wiring isn't quite the same, the above might give some pointers.

Vintage Yamaha Enduro Fans - 74-76 DT100 DT125 DT175 A B C Service Manual (yamaha-enduros.com)