How the fruit does this happen?

[hellrazor]

Open throttle - humming down the road on the way home before then - bbrraaaapppppppppppppp so loud - muffler shot out the back.

How does this happen?

These mufflers are pox, i've had a crap run with the lot of them.

 

[hellrazor]

whoops no attachment

 

[rotn50]

Now thats a blowout man, would of got a little fright for a second eh

 

[my67xr]

running too rich?
filling the muffler with fuel, then a long hard wot run, build up the heat, then bang.....

 

[hellrazor]

67 - funny you say that cause at the bottom end it was running a little lean and choking up a bit when i was taking off....
But it's on a RevMX with the standard OKo carby jetting like has been recommended on here and been running the same combo for like 4 months?