And yes, I have been searching for a while now.

72 CB750K
I'm wanting to put 19" Excel shouldered rims from Buchanons on my "poor man's" CR replica that I'm currently building.
I'm trying to give the illusion of the same wheel/tire size instead of going with 2 18's. Problem I'm having is finding a 19" rear tire to fit it.
The front, I'm going with the stock 3.25 x 19 (probably an avon speedmaster) the rear, I want to keep pretty close to the same overall diameter
as the stock 4.00 x 18. I'd like to have a 110, 120mm or a 4.25" width for the rear - probably a lower profile.
I'm not 100% with the speed master in the front, as I'm almost positive that I won't be able to find a vintage styled tire in that size (19")
At this point I'm open to ture suggestions. Anybody know a source for 19" rear tires in those widths ?