Engine Power Of A Thunderbird 900 Of 1995

I believe the thunderbird version of T300's had very mild cam timing , lower compression and most likely timing and carburetion to suit.
They ranged from your 50'odd to the super 111 which I think was just over 100'ish . But the super 3 was very hot cam's and had to pull a lot more rev's to do it.

 

It's just a guess, but are you sure it says 54 hp? And not 54 kW, pretty much equivalent to 70 hp?

 

Maybe the bike was for a different market, not Swiss.