I had exactly the same problem, back-fire on start up and a shatterd air-box resulting! Bust into about 8 bits arround the intake of the RH carb. Only the lid busted but recon it's the whole box that needs replacing.
You'd think Triumph would have put in a blow-back valve, of maybe they are using too much re-grind in their molding process! The remains of my air-box seemed very brittel!!
Kenny
