What is the alternative to a 110/90-16 REAR motorcycle tire?

I've been searching and searching and can't find anything that matches a rear tire for my inherited 1982 Honda Custom CM250C. It is listed as 110/90-16 or 110/90S16 - which would be like a 4.25"tire or MP85. Of the few tires I can find on bikebandit and other sites, they all say"front"tire. I just really want a generic cheap tire to get this"learner"bike going. I did find the matching sized tubes, just not the tires. The FRONT tire is a 3.25S18 4PR (translates to about a 100/90-18, which I can find).I'm not seeing a 110/100-16 anywhere either?So if it exists, a rear 110/100 would work, but just be harder to get on?Can you only go bigger? And how much bigger can you go? Should the front tire be changed any if the back tire is not standard?In theory would a 120/90-16 tire work to replace a 110/90-16. I can find that in a REAR tire.Thanks SOOOO much!!! I asked another question about tube size to go with the new tire size...

JC WHITNEY claims 3 different models of tires especially chosen for your motorcycle, and indeed I think they chose a fatter tire for the rear. It's a slender reed, but I think I'd go with it and the Kenda tires.Cheng Shin Barracuda,Street Tread, AndKenda K671 Cruiser tires130/90-16 Rear K671 Cruiser ST TireThis is speed rated to 130 mph, $58They have front and rear tires specified.Hope this helps. I took mine to the dealer and said put some new tires on it. Got a fairly nice set of Cheng shins and Tubes though my rims will accept tubeless.