New bike backfiring

[munch9]

Hi guys today was the first time I used my wpb race 140 and I could hear it backfiring now and then and then my mate told me there were flames coming out of the exhaust.. I stopped and gave it a bit of throttle and blue flames started to come out of the exhaust. Turns out the exhaust was a bit lose could this have been the cause? If not what is causing this? Not even 1 hours use!

[robbo24]

Bikes will pop and bang with a loose exhaust as they draw air