Hi DSTREB!!!
Welcome to our new little site

... There are Federal and probably State laws that cover you question (Is it the Moss Furgeson act? Is that close? I'm not a lawyer), but essentially it states you can do your own service and still be covered under warranty. Save your reciepts, of course, and it wouldn't hurt to use Triumph parts... that way there is no dispute if something goes wrong. You could possibly use an oil with a anti friction agent that could mess with your clutch, as an example, and that may void the warranty on your clutch.
Its always best to have somekind of relationship with your dealer... you may actually need his help someday. There a quite a few people who don't like dealers, but I've always tried to work with mine. Plus, they know things like current TSB's and recalls or just plain fixes for quirks that you wouldn't know about. I like going to my dealer... its always a good time.
Here I am shooting my mouth off on your dime...Please... join in!!