...wow...200 bucks...wow...
..i bought a 05 junker Marshin for 20 bucks, that i'm using for some spare parts..lol...
..my first belt lasted 30,000km...so, unless it's dry-rotted from not being used, it should be ok...
..get yourself a new spark plug...
..the rollers will begin to develope flat spots pretty quickly, but might last 10,000-15,000 km without much performance drop...
..with the derestrictions you've did already, you should check your carburetor's main jet...stock is an 80 and you could probably use an 82 or 84...
..next, get rid of the stock airbox, and install a free-flow filter...then re-jet your carb again...lol..
..my preference for cvt parts would be Malossi...
...but for stock replacement parts, go to stadiumyamaha.com...and mention that you are on this forum...
..this a lnk to the Agility 50 service manual...you will need this...
http://www.eserviceinfo.com/downloadsm/35810/Kymco_Agility%2050.html...oh, and Welcome to the Forum!!!
peace