Richen, depends on the carb, slide carbs require you to take it apart and change the main jet. if you have a diaphragm carb there will be 2 screws right next to each other, backing out the H one will richen the high end mixture.
4 stroking is when a 2 stroke misses every other hit, properly set up a 2 stroke will not hit max RPM on the stand it will go WAAAAAAAAAAAAAAAAAAAAAAA BOGGGGGGGGGGGG WAAAAAAAAAAAAAAA BOGGGGGGG, the bog being 4 stroking. I need to make a video of this.