Welcome Kymco Owners!
Get a set of 6-7 gr Dr. Pulley sliders or Ninja sliders. Also get these... http://www.partsforscooters.com/151-37-Slide_piece_qmb139?sc=38&category=138773Sliders will last 10 - 15 times as long, and work MUCH better. Look at, and follow the instruction to be SURE they are installed correctly.Get a new contra spring too (2000)
I think around 7 is stock. you can do just weights, but weights along with stronger contra spring will make a HUGE difference.
Have any idea what the stock spring is? Heard its an 850 spring. If so, wonder which is best, 1000, 1500, 2000 to upgrade to? Whats the difference? I read wordslinger likes a 1500, but i dont know if his a50 is modded? Another guy said he used a 2000 and he lost alot of top end speed, so he went back to stock. So idk lol!! Also, since im here, im a little confused as to why i have a 12v 4amp battery from dealer instead of a 6amp like the manual says i should have, thought that was strange? It has a GTX5L-BS in it btw. Im thinking the reason they did that was because its cheaper to install a 4amp for the dealer?? Either that or my manual has a typo?
Make sure that if you Kymco dealer does install the de-restricted boss that they also up-jet the carb so the bike is not running lean at high rpms.