Hey yall. Brand new to bikes and picked up an 1978 xs400 from a shop a few months back. They said they fully redid the carb. I have a weird problem where the bike only starts and runs with the choke on halfway, and it dies when I push it in either direction. Also the bike will die when I leave it running for 10ish minutes. Checked the air filter. Spark plugs are brand new and look terrible and sooty. When I take it out it dies whenever I come to a stop. Please advise, thanks!