Rebuilt the stock Dellorto UB24 and reinstalled it on the bike with a velocity stack in place of the air filter. Jetted up the main from 100 to 108, can't seem to find the needle jet for this bike in any other size other than the stock 260. Replaced all seals and did a good carb clean, didn't replace the float... When I bought the bike the guy had a really hard time starting it (I think it was because the valves were out of adjustment which I fixed), but he only filled the float bowl with gas, he didn't put any in the tank. Once I got the tank and put a little gas in it (today) I found the carb was flooding big time, despite the float arm being set at the right height. Since that's the only thing not replaced, I think I'll go ahead with that, there's plenty of NOS ones around. A couple hours after this vid I kept the petcock closed and started the bike (third kick), and everything sounded great, idled nice and steady as well. The second I opened the petcock the carb flooded and bogged the engine down
Additionally, getting the bike running revealed an exhaust header leak at the flange, noticed a little gas along the intake elbow as well, but that might have been from flooding the float bowl
Took the seat to my retired tailor Dad for some reupholstery help. Decided the foam padding was too far gone so never got around to riveting the new seat cover, this got me weighing out some options with the seat, mainly to keep it stock or go custom. There's a professional auto upholstering guy a mile away, going to check in with him to get some opinions and prices.