smoke from silencer

No, No problems.. It just means that your front pipe is (maybe)caked with deposits that are still hot when you stop riding and continue to slowly burned or smolder..

Try burning your pipes out if your not worried about discoloring them.. Heat them with a torch(propane and off the quad ofcourse). Get them hot, and then point the flame into the exhaust inlet. If it catches fire this is a sigh that theres a lot of stuff in there.. Burning this stuff out can also give you a tad of performance by freeing up some blockage and will make the exhaust a bit lighter.. And it may sound more Ring-Ping-Ringy as the deposits muffle the vibrations..
 
do this.. get your self 2 cans of a good carb cleaner, and 2 stroke silencer packing...

tkae the pipe off, take silencer apart.. inspect packing is it oily?? and black or pink or white.. blast out the inside of the silencer with carb cleaner. and do the same to the front pipe... let it dry good, ( can flush it out with a hose if you want) re pack silencer reinstal and go riding