We haven't yet developed a carburetor kit for the SR500, thought may be in the works this year. This carb would be an excellent choice for the SR, but you would need to determine if the carburetor will fit in the same space as the original carb; if the engine-side spigot would fit (42mm), if the air box boot would fit the intake bell (54mm); and if the same cables could be used. If the engine side spigot is not the same, perhaps another Mikuni manifold adapter can be used:
You would also need to determine what jetting would work best for your bike. I have attached a link for an article showing how to tune and jet a Mikuni carb below. This is what we do when we build a kit for a bike. You may be able to find jetting specs on one of the user groups. I'm sure someone has used this carb on a SR500, a TT500, or XT500.
I have attached a couple of links that might help you in putting this carb on your bike:
There is no provision for a vacuum port on this carb, so you could not draw vacuum from the carb, but you may be able to add a vacuum nipple to the intake manifold, or turn the petcock on manually.