Moped Army

I've done a lot of searching. You'll see I've only posted on here a couple times. I got a '78 Motobecane Mobylette with the 50v, and though i believe it is just the single gear, I don't quite believe it can still do 35+ on an engine with 6k miles and a fuel tank with a hole somewhere in the seam.

I have a parts frame that doesn't run. The tank is good! I was running fuel from the petcock in the spare tank to the running motor I had standing. I was thinking of breaking down the whole main bike and swapping it over, but really, most of the main frame the bike I'm talking about consists of is really well kept and rust free; alas the tank on the other is good. Straight swap, best of both, clean, order, reassemble?

The timing feels forward, but I haven't gotten it to quite fire yet. I bought the correct spark plugs at kragen from a cute girl. i researched ahead. I should have asked her out. Alas I don't have a spark plug socket or any sockets for that matter (lost all my tools over two moves).

I've searched and come across so many threads that say "search for other threads" but after a while it get's redundant. Real info, right here, _please_?

Have the Gurtner carb. it seems to work alright, albeit ugly. Everyone upgrades? Review your carb setup.

I bought a putty material for metal but it cringes when exposed to gas. I am unsure of the products short to long term hold strength for repairing the hole in the pinch seam.

Would a direct swap be more viable? i.e. disassemble, clean, replace, upgrade, reassemble.

There's a plethora of kits. Can someone put me in the loop? I like the porting and rebuilding angle. I can weld, however how does one tune a pipe?

I lived in Portland, and never got a moped, till now. :(