1981 Honda CB750C Starting issuses

[Sxevon]

I just recently bought a 1981 Honda. Ran great, needed new pipes gave it a tune up and continued to run perfect as long as you allowed it to warm up. Just within the past week if I try to start it all you hear is the starter spinning. All lights work so it's not the battery, and you hear it chug once and a while just a little bit. Now would this be the starter or something even more major. I did get it to start once last week after it started this, but if I allowed choke to go in it would start to chug and would have probably stalled if I didn't pull the choke all the way back out.