engine cut out, sparks and shit out the exhaust

so i was riding down this back country road on me aerox (the notoriously shit one) when it just suddenly stops! the clocks just die and go dark, no throttle at all, not even an attempt to restart! my mate who was behind said he saw sparks/fire coming out the exhaust and could feel like some stoney shit hitting his face. i feelif theres compression and theres pretty much none.

so heres me thinking like the pistons shattered or the rings snapped, simple fix right...
got it home and strip it, and theres NOTHING out the ordinary. it suddenly has loads of compression, turns over fine, plugs a good colour, no abnormal shit on the piston top.

anyone have any idea what couldve happened?

 

What exhaust does it have?

 

yasuni z i think

 

are the reeds still intact ? have you checked the exhaust to see if the internal baffles aare still in there ? or the packing in the end can ?

 

reeds are fine, havnt checked the pipe though yet

 

If its spitting stuff out, either your crank is giving up Your piston or rings are on there way out, Its a weird one because it wouldnt do that for no reason, Yeah sure on the rare occasion they will backfire, however the fact its spitting stuff out is a sign of something bad

 

did you actually take the barrel off and see the rings? what about the head gasket, ,maybe it failed and some got like sucked into the motor?

 

yea checked it, all fine. reckon it might be the bowl on the carb emptying then running stupidly lean and backfiring. then the backfire damaged the baffles partly and flew out.

its the only half logical explaination i can think of

 

sounds good to me