Have you ever seen this before?

[Milan]

These pipes came off the 350 I am working on.
The one in another post that is only running in 1 cylinder.

Do you think, while the PO was riding, if the 1 cylinder stopped firing, would this have caused this blowout?

[Ws76133]

I'd think it could if the spark returned after the silencer and chamber filled with unburned fuel.  When I was in high school, admittedly years ago, I'd switch the ignition off on my car while rolling down the road; turning it back on gave a loud backfire.  One of those opened the muffler along the weld seam.

[msr]

To this day, my 50+ year old brother will do this on any carbureted bike he owns.

[Striker1423]

To this day, my 50+ year old brother will do this on any carbureted bike he owns.

[m in sc]

 



I mean.. yeah.

[RDFL]

Wonder if he filled his pants when it blew.

[rodneya]

I cant see that blowing up being the cause of that. It would have ballooned out a bit at least. There is also other damage on the tube a bit closer to the stinger.
Ive had really bad backfires pop the pipe off at the cylinder flange as that's probably the easiest spot to release pressure.

[m in sc]

agreed. that wasnt a backfire issue IMHO either, but i bet theres a good story there. My guess would be a crack in the aluminum that wasn't caught in time and eventually got completely out of hand. 

[teazer]

^^^^

What he said.

That's not an explosion type failure.  If you look at the ragged edge you will probably see dirty parts where it was cracked for a long time and siny parts where the two parts fretted against each other. It does look like a fatigue crack.