OK, I'd do this:
Remove the belt. Snug both front and rear nuts, a little.
Is there any play up/down/fore/aft in the front assembly, or in the rear?
Front shaft bearing good?......Rear shaft bearing or bearings in clutch good?
If I didn't find movement in those shafts or assemblies, I'd look at the rollers and if they are correct size and in good health (NO lube in there!) relax....it is belt slap caused by the belt.
If I really couldn't live with the belt slap, I'd try a 2nd stock Kymco belt. If that didn't help, I'd install a new clutch. @$100 for my LIKE200i, fully assembled.
Stig
Stig - there is some play in the front shaft, without the pulleys installed I can pull it out and push back a little, probably 1/10th of an inch or so. The rear is fine. The clutch installed, there is a definite play rolling the bell over, but as Karl mentioned before, that is absolutely normal. The rollers are OEM stock 23*18mm / 20gr rollers, brand new, installed not 50 miles ago. I did not lube anything in the rollers area, but the inner sleeve I have cleaned today of the lithium grease I put in the other day and used some moly lube, as Karl suggested. I aslo greased the needle bearing of the clutch, it is fine, turn around without any hiccups, so is the front bearing. Funnily enough with all this hassle I start to be back at ground zero - meaning just before I touched anything in there. The clutch chatter is not much pronounced (but audible) and the front pulley belt slap is much reduced to the decel stage of a couple of seconds. I do suspect the clutch assemby, it does not close properly sometimes, and I have to twist the pulley faces in order to get them apart at the beginning stage, but then I can push them apart by a simple pushing motion, rather than the twisting. I do not have the special clutch holidng tool, or the special narrow spanner for the thin nut, I guess, I could get by with an impact tool, but I'm somewhat afraid to take that bit apart and making matters worse (that huge spring looks to be a nightmare to hold, whilst installing the thin nut without the special tool) Anybody has got a handy tip, how to diy the thing?
Oh btw, I forgot to mention, on one of the previous occasions we spoke about the clunk if the front and how soft the dampening is. Well, I have added some 0.5dl of 10W fork oil to the forks, and it changed the whole mushy crap, that was my front to a hard, but very responsive feeling. The oil smelled in there rather gross, but I do not have a large quantity of fork oil at the moment, so replacing the old stuff will have to come later.