i just picked up a 15 year old cbr600 so i was thinking it probably needs a good tune up so its not quite as easy as a tire change. so probably a carb clean and balance maybe a valve adjustment
I've always dealt with Denny at TSR in Georgetown. It's not Mississauga but it's close and I trust him.
If you want a no BS check up and you're not sure what to look for he's my recommendation.
http://www.tsrltd.com/