77 Kz1000 tire sizes?

I have a 19" front rim and 16" rear. I would like to put a set of Avons on my 77 KZ and I'm needing size recommendations. My front is a 3.25 and the rear is a 130/90. Should or could I go larger or just stick with the sizes on the bike now? I bought the bike in 85 and it has tubeless tires, of course with tubes inside. Is this a safe combination? One last question, should I go with bias ply or radials? I'm open to tire brand recommendations as well. I know my vehicles like certain brand of tires and I'm sure my KZ does as well. The tires on the bike now are Continentals and never could get the vibration out them no matter what the mechanic did. Tire or rim, the problem, who knows. Advice will be greatly appreciated.

You actually don't say which Z1000 you have (either a A model with an LTD rear or an LTD ( model). In either case you should avoid the radials. Since you are running tubes in your tires, can we assume you have spoked rims? If that is the case, then you are running a 'harley' rear hub? If you have converted to mags (either Lester or LTD) then you need not run tubes. Stay as close to stock as you can get (although you can go slightly wider on the rear).