It did happen to mine not long after installing the BB but it's just coincidental. Triumph made a design change in about 07 to correct the problem. The inside socket (part of the engine casing) for the idler gear shaft was weak. The newer engine casings have a beefed up socket.
My bike was off warranty almost 8 months, but my dealer was able to get Triumph to cover it. It took a long time (over a month) to get a new casing from England. My bike was in the shop almost two months. The starter broke just as I was picking it up from a follow up service check after a 1000 miles on the BB.
I guess I was lucky. Triumph claims there is only a 2% failure rate, but have done a lot of replacements out of warranty. Get your dealer to help.
