At this point I'm in the habit of buying everything in sets with all the sizes available. It seems Triumph makes it a habit of using a number of different types of fasteners and in the oddest sizs they can find. I seem to always be looking for a tool in a size that I don't have. When I did the forks on my Trophy I bought a set of large sockets knowing I'd need one to loosen the fork caps the set included - 19,20,21,22,23,25,27mm surely it would be one of those, nope 24mm!!!
I already have a set of meteric sockets but when I was in Sears two weeks ago they were selling a 10 or 11 piece set for $10. 8mm - 18mm I think, 6 point 3/8ths drive. Couldn't pass that up especially since it included all the sizes in that range.
Let us know if you find that 19mm hex bit.
Keith