I would not run a radial tire on these bikes, as they were not designed for radials. Radial tires are made differently, and bikes which come with them from the factory, were designed for this type of tire. Your bike was designed to run on bias ply tires only.
I would suggest two new, matching tires. The best wet traction tires I've found are
Pirelli MT66 Route tires. Rode four days in the rain, two up, bike overloaded, back in 2009 -- a '79 CB750K. The bike felt like it was glued to the roadway, slightly leaning, at 60 MPH/95 KPH, in curves. They're the only tire I will run on after that.
Otherwise, if you have a tire in mind, type its name into your preferred search engine, looking for reviews: "Pirelli MT66 Route tire review". Best of luck. Cheers!
1979 CB750K (sold, 2012, but not forgotten)
1983 Kawasaki 440 LTD Belt Drive (sold, 2011)
1993 Kawasaki Voyager XII