Circuit pipe woes

My Austro Diamler is an excellent bike. It handles nice, rides smooth, always runs and looks like Robocop turned into a moped. About two months ago I was riding it to Moped Monday. Headed down a dark and dangerous street, my headlight didn't cast enough warning and I hit a huge pot hole. It banged very loud. I heard a scraping noise, and look behind me to see my tail-light, still lit, dragging behind me bouncing along the road, and then suddenly it lets go and becomes black as it slides to a stop. AD's gas tank is plastic and great, except for the fact that the only thing that holds the tank under the frame is the tail light. I know, pretty stupid. Perhaps the rear fender played some role, but I dont' know, I've never had one. With the light gone, I realize the gas tank is dragging on the rear wheel and now my moped is very loud. I get the light, put it in my bag, reach behind me with my left hand and hold the gas tank up while I drive home with the other. I put it in time-out, not because the moped misbehaved so much, as I wanted to punish the engineers. Last week I zip tied the tank on and took it for a ride, and it was still incredibly loud. I tightened up the exhaust cap screws, but they were both snug. When the motor was running, I could feel exhaust with my hand. In spite of the air leak, I rode this bike to Moped Monday last week, and every time I hit a bump I was relieved to see the pipe was still with me. I didn't really think about the danger involved until I was driving at 35mph down a bumpy street, imagining the header snapping clean off, throwing that big metal snail right under my rear wheel. I pulled the pipe to inspect it and here is what I saw.
The subframe pivot must have pushed the circuit pipe down low enough to connect with the pavement when I hit that pot hole, cracking my header. I'll take this pipe down to the shop and weld it up sometime next week. I'm not sure if I can get a TIG torch in there or not, we will see.