I had the exact same problem at about 35k on a 2001 Daytona. Turns out one of the coils had gone. My dealer replaced all three, and made Triumph pay the bill saying that it shouldnt've happened. My bike was not under warranty at the time.
The good news is you can limp it around if you let it cool off. I was 4 states away when mine went out. Rode it home.
Contact Todd at
www.rideteamtriumph.com for specifics as to what he did.