I am running 32.5's. A larger is a must, I would say a 27.5 would be fine, if not then a 30 will do it. Mine was running on a 32.5 on one side and a 27.5 on the other when I bought my bike used. And the guy I got it from gave me a reciept that it was jetted from Trinity, go figure. I had problems launching on second, and hard on cold starts. Now with 32.5's I can launch very clean.
If you buy a used bike it's always good to go through it b4 you start dealing with headaches assuming the other guy should have it tunes or something.