Compression problems

[indigojoker]

Major backfire, lost compression- HELP!!!

Hey guys, I'm a newbie and am having a problem. I have a KX 250 and have lost compression. I was riding most of the weekend and late on Sunday I was riding slow and suddenly had a big backfire (or it sounded like one), then the bike bogged and died and I lost almost all compression. It had been running rich (dark plugs) but otherwise great.
I'm guessing I either lost pressure from the rings or worse, the piston blew up. I was gonna rebuild the top end or at least try to, but didnt know if that was the total problem. I'm just hoping I didnt blow the entire motor.....
Any help would be GREAT! :bang:

 

[Ol'89r]

and suddenly had a big backfire (or it sounded like one), then the bike bogged and died and I lost almost all compression.
I'm guessing I either lost pressure from the rings or worse, the piston blew up.

Your guess is as good as ours. Take it apart.

 

[Papakeith]

The best way to tell is to pull the cylinder and take a look.

 

[Chili]

Im going to merge this with your other thread please do not cross post the same question in multiple forums.