Hi, I have a 1973 Honda Cb500//four. When I bought it it ran only on choke. I Cleaned the carbs, replaced sparkplugs, and sparkplug caps. I got it to run yesterday and it ran well with the choke off. I turned it on this morning and it ran well, then it turned off on its own. By then i had to leave to work. When i got home i turned it on again and turned it on. It ran for 30 seconds and turned off. After that it will start but only if give it throttle, but it will turn off after i let the throttle go, even if i hold it at 4k revs for like a minute. also it will only turn on with the choke off.