Meh, I've only had it up to 75 the only time I gave it some throttle, or at least that's when I glanced down.
I think it will hit 110 maybe, there's no oil spout for 5th gear though so you can't be as hard on it as the first four. It's supposed to be a good wheelie machine with the twin carburetors though for some reason(there's not many Yamaha XT's around here, it's mostly a European model).
I got a new spark plug today and everything is good now, just my main fuel tank is a little gummed up, so I will have to clean out the fuel tank here sooner or later. It works on reserve though... lol