[dogscoff]

I have a mount and that mount must be available only to one race. How do I do that?

I have no racial specific tech to bind it to. So how do I solve this?

As far as I know the ONLY way to create a race-specific technology is to use racial techs. You'll need to create a new racial tech and put your mount in that tech tree.

Or, if I'm misunderstanding you, you need to create a hull size that ONLY your race can research (ie a destroyer of 301kt that can only be built by your race) na drestrict your mount to that size (this mount can only be used on hulls of exactly 301kt.)