I know the 4rt clutch has been discussed before but I have been trying to sort mine and think I found an answer (there may be others!).

mine is a 2006 4rt -  in the past I've used Elf, Putoline GP10 and ATF dextron II & III with the same results - a dragging clutch... At best I get a lurch forward when selecting 1st or 2nd from neutral, at worst I cant change gear.

I did fit dimpled plates last year, the first time that I started the bike up and put into gear I shot across the garden... the eventual fix was to de-burr the shear edge formed when they had been stamped out. This edge was rounded off with a file and polished and the clutch drag improved but was still there to a degree. Again using Elf or Putoline didn't improve things over using ATF so I've stayed with ATF - its cheaper!

Over the last few weeks the gear change has been getting worse... to a point where its impossible to change gear.

The basket has been out a few times, all the internal linkage is in good order and without the basket in the bike it will go through the gears with ease...

On the fingers of the basket on the driving side, there were the lightest of ripples on the face. I had already filed some of the ripples out some time ago, this time I filed them out completely,  draw-filed them smooth and then polished the faces with 400 grit wet/dry paper and put a 1mm chamfer on the inner edge. I also put a 0.5mm chamfer on the friction plate fingers that run in the basket. The result is a gear change that is effortless!...I can go up and down the gears with ease and I can even find neutral which until now was only achievable with the bike not running, still with relatively cheap ATF in the bike...   

this may not work for others but it maybe another option if you have issues......

 

 That is all good, but normal wear for a 12 year old bike. Just how long have you owned it? I would be more concerned about the cracking around the foot peg mounts.