collis

ok, it looks like my nice relaxed week off work next week and been put of hold till the next time...

I was riding my bike (2001 curvy) to work yesterday morning when suddenly top end power just died and started making a rough grinding noise, sounded very much like it was fireing on the exhaust instead of at the top.
Then on my way home, the last half a mile the bike struggled to do pretty much anything even tickover. The engine was fireing only on the exhaust (from the sounds of it) and was extreemly loud.
My suspicion is... one of my cam chain tensioners has litterally given up, possibly the chain has bounced inside it and then grinded the tensioner flat.
For the last few days is has intermittently made a little grinding every now and again (generally around 5-6k rpm) but I simply thought that it was where my front brakes need new pads, bike pulled in every gear as it is ment to... not any more though.

The only thing i'm wondering is can you inspect the CCT's with the engine in situe on the bike and can they be replaced the same?
I guess I'll need to remove the fuel tank and the airbox to get to everything.
Also is there an easy way to isolate which CCT is the faulty one seeing as there are 4 of them 2 on each side (if i'm correct) unless there is another gear somewhere that needs to be checked as well?

Thanks in advance.
Collis