Big Problem

My 2007 Carpentered bike has been performing perfectly until today. I started it up and immediately, the normal sequence was different. Usually it is a rev to 2000 rpm and then a settle down to just under 1000 rpm. Today..it seemed dead with no revving and actually died once or twice.
Today..The idle seemed lopey and unusually rough.. As I opened the throttle a bit, it was apparent that the engine is running on two cylinders and then I began to hear clattering from the engine.
I decided to ride it and am getting far less power than normal and backfiring like crazy. Has a valve been dropped or a valve spring broken??
The cam chain was adjusted a few hundred miles ago so I doubt that is the issue. I will check to be sure the plug wires and coils ore ok but it is the clattering noise that worries me and cannot be explained by ignition failure.
Thoughts??

Oh dear, sorry to read that. certainly worth checking for a spark on the cyclinder that isn't working properly. Hopefully it may be something simple and related. I'm sure the consequences would be much more dire if you'd dropped a valve. Can you do a compression checkon that cylinder? That would also confirm it.

Good luck

Zen when you adjusted the tensioner how much did you have to turn it in? Oh and I am sure you will be asked what brand and grade of oil are you running?

Coil Leads??