throttle problems

Okay to start off I just want to let everyone know that I am brand spanking new to motorcycles but I am fairly mechanically savvy. So to start, I bought the motorcycle a couple weeks ago thinking that it ran perfectly, which it did for the 15 minutes they had it running, but after the paperwork...

I've been reading this forum for about a month now. I've tried just about everything on this site so far but my bike still won't work. I have a 1979 xs400e (I think). All original everything. It was given to me after sitting for almost a year in the sun. I had ridden it and it ran great...