2010 Triumph Thunderbird Engine problems

This happens when shutting the throttle off to make a corner or a stop light, or to adjust speed in traffic. The engine backfires through the intake of the throttle bodies and the airbox under the vehicle seat and dies. There is no warning this is about to happen and the engines dies and you are stranded in traffic while you coast to a stop, find neutral and the engine usually starts as nothing has happened and runs normally until the next time. *Tr