Noise/feeling ? Not CCT! :)
 

OK guys, as I am at rebuilding my lightly crashed FireStorm... oh, sorry it is Shawk on your side ;) I realized that for last 4000 km I had some strange problem that was getting worse...but I forgot about it because of accident I had later and other damage.
Here comes. When I ride it in any gear at any speed with my left foot I feel (rather than hear) kinda noise, like something rubbing against something with period approximately same with full chain "circle". After actually really noticing it about 2500 km ago I was putting it down to stiff link in the chain, but could not do much being in wonderful deep countryside of France with not much access to services :) But when I got to disassembling bike at home, removing final drive and really checked chain for stiff links I did not quite found any. I mean - I never seen an stuck link on X-ring DID, may be I just do not know what it should be like?
Other thing is that front sprocket is quite shot. No, it still got all teeth but they...well, worn beyond service and rubber/plastic damper on front sprocket worn to into "chain" form. But on all my bikes before I did wear sprocket to that level and did not have this kind of noise/vibration. I also clearly feel bike "pulsing" forward way more than you can put down to engine, more like my single-cylinder 800cc Suzuki enduro than Storm. Engine thou works fine, I mean - fine, no probs at all. And weird pulsation does not dissapear with clutch pulled.
What bothering me - perhaps it is nothing to do with chain? could it be that it is something up in transmittion? But then - it does with with clutch pulled in too!
Could it be somehow that gearbox output shaft bearing is gone bad? I did not drive with too tight chain thou, I mean - at all.
Did anybody ever experienced such reaction of Storm to badly worn chain and front sprocket?
Yes, and I did check rear wheel bearings - they are fine.
Bike got now 60 000 km on the clock, and never missed a bit or did anything wrong except this....

Have you used a rear stand and rotated the rear wheel to see if there is anything bent, wobbling, or not aligned? How about brakes, rear in particular? Is it dragging? I doubt an output shaft bearing or would be the problem. You'd probably hear that and it would self destruct rather quickly I'd think. It also wouldn't have enough friction to where you'd feel it riding. Have you checked the cush drive/rubber inserts to make sure they are in good condition? That's about all I can think of at the moment.

I have checked all, rotated rear wheel with chain on and it's kind of little resistant to turn at particular part of the turn, but not each rotation, I'd say about 1 "resistant turn moment " per 2 rotations approximately. Dissapeared when I removed chain and rotated wheel again.
One thing might be spot on. Cush drive. Inserts worn too much I think, I can feel serious gap when I'm holding rear sprocket and trying to rotate wheel. And when I disassmbled rear hub on one of cush drive inserts "connecitng" piece of rubber that keeps two parts of insert together was broken. Is it possible that worn cush drive causing such "rubbing" effect?

I had a similar issue on my 98'. Could feel some what of a faint vibration being felt in the left foot peg, with an occasional "pop" noise. Checked the chain and found no binding links. Went for a ride with one of the guy's from work one afternoon and the vibration got alot worse on the way back home, but there was no pop noise this time. Pulled over to check for anything obvious. Pulled through a parking lot while the guy from work followed behind. He came rushing up beside me and siad my rear wheel was wobbling a little. Ended up being the bearing on the left side of the wheel had catastrophically failed. Just my experience though.

There are three bearings on the rear wheel. One on the sprocket carrier, two on the hub. I suggest you check them all.

Thank you guys! Will disassemble rear wheel properly and will check for bearings state...just to be on safe side ;)