Here's a link reagrding this subject:Luggage Rack Post

I don't own the seat rail (yet). The Harley luggage rack might not be compatible with the Triumph seat rail. The mounting point that's shared between the luggage rack and seat rail may not be condusive to use with the Harley luggage rack.

You would need an America style single seat and its mounting bolt to use either luggage rack on your bike.

Keep in mind the luggage rack is only rated for 10-15lbs, so it's mainly for "show", or one 12 pack of beer when tie downs are used.