7/8's
Awesome, so it's a 1" post with a 7/8" inner? Get a banger quill stem. Put some banger bars in the stem. Insert the stem into the post, tighten it down, and use your superhuman gorilla strength to twist/pull the post out. The bars will provide leverage. Do not try this with any bars/stems that you care about; they may well be destroyed.
Ok.. So what does a banger quill look like.? Sorry
There's enough tubing for a seat post clamp also I like the idea of the stem wedge like you have pictured...It looks like there's a hacksaw cut on the old stem already, maybe they gave up. I wrap a cloth or use a heavy glove when using a hacksaw blade, it's a lot of work.
If they cut the post and frame down to the top tube, then the problem will be tightening the replacement seat stem. Is there room above the top tube for a collar to tighten the stem? If not, you could have the new stem tack welded in place, or customize the stem to tighten up like the old AMF stems, like a handlebar stem. You would have to find a bolt and wedge from a handlebar stem, then cut the new seat stem to have the wedge slide up and tighten. Then you could adjust it.
Thanks for the feedback on the "Banger Stem" defenition.. Yeah I was thinking about the dementions on the ID on the seat post also.. Unless if I get the correct ID tubing that would fit inside the seat post and create a wedge and bolt set to fit. and maybe weld a larger bolt head on top to get a closed socket and attach a breaker bar. Then spray some PB Blast lube and little by little twist and turn to loosen the seat post out.. Maybe heat it up with a torch.. I wish there was a way to thank the D.A. that cut this seat post up.!!! URRGGG.!!!
