Yamaha RZ250r backfiring on left cylinder

[Antman]

My left cylinder is backfiring, and the bike does not rev as well as it usually does. I did over rev it whilst changing down during a high speed overte. The problem occurred within a couple of minutes after this.

Any ideas?

If only life had a Cmd/Ctrl Z

[Max Preload]

Lack of compression on that cylinder. I'd say the top of the piston missing it's edges, maybe even a small hole in it.

[Yow Ling]

replace the plugs, if problem persists seek medical advice. Look for a simple problem first. Rz CDIs used to fail with dry joints maybe another reason for misfire. They can stand beingover reved more than you might think

[Ixion]

Another big picture for the ringa-a-dinga-ding forum of a piston with a hole in it.

Head off, and inspect.

[Antman]

Thanks for your replies. I guess I'll try my spare CDI, then whip off the cylinder head. I'm a shit mechanic, so I guess it will be grazed knuckles, swearing and flying spanners!