Fresh out of hibernation

Recently released my beast from its shackles of storage. I have not seen her in soooo long (4 years). She was well taken care of and maintained. It was more like running and fixing storage as I had a great friend, with the space and motorcycle know how to do some work on her while I was out of state and keep her in first-crank-start-up-mode. Been going over the bike, 76 KZ900 and seems I might have an issue that I thought I would ask an opinion about. On one exhaust side there is white smoke coming out, just a trace but still there. Should I be concerned right off or just keep an eye on it as I ride. Have not ridden any long distance yet, just around the neighborhood. Is compression test and spark plug my first line in detecting the issue. Other wise then the slight smoke she runs smooth with no audible or visual issues.
Thanks everyone for your help, it's time to ride!!!!

throw some good plugs in her and take it out and beat it up for a good ways.
probably valve seals from sitting.Check for good spark on all 4.