i started my bike this afternoon (full choke, had already been run 50kms in the morning) and it was a bit quieter than usual, and then bang

the motor is stock with a daytona filter, kiss d-r box and has race exhaust chambers/cans (cant spot any branding on them but they are freaking loud, the right chamber touches the fairing, they have springs holding them to the cylinders and are connected to one another below the rear susp spring, sound familiar to anyone?)
ok thanks

Tim