Hey John, and welcome Tigerfox.
I have the same vibration, that is, if you have similar symptoms as this.
Accelerating up through the gears is fine, smooth and lovely, but as you roll off the throttle between 3 and 4,000 rpm you get a vibration on an even throttle. I know you said 2,500, but I don't ride that low usually.
I've re-mapped using the Triumph off road pipe map, but still have the standard pipe. This makes the bike run a little richer at those revs. I've also adjusted the chain to about 60mm slack, ON THE SIDE STAND, measured half way, in the usual manner. This reduced the vibration to almost negligable, and everyone I've spoken to, both at the Triumph dealer, and a local independant have suggested that it's perfectly normal, and would more than likely change again when the sprocket and chain were changed. I've also noticed it's less noticeable when I've lubed the chain. The tyres also can create a vibration, if you have the Anakees especially.
The best way to check the actual chain tension is to sit rider and pillion on the bike and check the slack then. If it's set to factory specs, loaded it will be piano string tight.
Good luck with it, it may be something you just get used to, but if there is something additional the dealer finds, I hope you'll share it here!
Mick
