I just did the forks on my Vento and it was very easy, I rebuild mountain bike suspension for a living though! These scooter forks are much simpler! You don't need any special tools. The only somewhat uncommon one is usually an allen wrench attached to a socket for removing the bolt inside the fork at the very bottom which holds the lower leg and stanchion tube together. On my Vento I used an 8mm allen socket attached to two long extensions.
You can loosen the two pinch bolts in the crown and the whole lower assembly can be removed. Then you will remove the top cap. The spring underneath is under a little tension, but not enough to shoot anything out, just be ready for it. Then remove the spring and drain the oil. Next is where the long allen wrench comes in. It is located all the way at the bottom inside the tube. I had to gently clamp the lower section in a vice to loosen this bolt. Once you get it undone, the stanchion tube should slide out of the lower legs. Then you gently pry out the old oil seal. I have found that a open ended wrench works well for this, just be careful not to gouge into the leg itself. To install the new seal, apply some fork oil, or even better, fork grease, I like slick honey (used for mt. bikes). The seal sometimes be pressed in with a large socket that fits just around the outer flange, also an aerosol can the right size can be used. Then just reassemble everything in reverse. Put some blue loctite on the inside allen bolt. Fill with the specified weight and volume of oil (you may try calling Kymco for this), and your ready to ride!
Feel free to ask any questions for further clarification, I hope this makes sense!
