I have never been able to find a shop willing to work on a motorcycle tire. Sorry I don’t have any information that can help.
Where is the leak and what kind of tire is it? I ran across a good article on this a few years ago: https://www.motorcyclistonline.com/tire-repair-plugs-should-you-use-plugs-on-motorcycle-tires. Some tire manufacturers don’t EVEN recommend emergency plugs and that could be the reasons shops won’t repair. And even if the tire manufacturer does allow repairs, they have a whole host of criteria that must be followed about where the repair can be made and how.
(Sorry this is in all-caps, I can’t seem to make the reply do anything else)