I have a 1986 honda fourtrax 125 that leaks a little bit of oil when you start moving how can i fix this?

Without any more info, I can only say look for the leak's point of occurrence. If you see oil on the bottom or side of the engine, follow the oil trail upwards to the farthest point. Replace the gasket in that area. If you're a poor boy like me, dry the leaky oil spot up ';and I do mean dry';, and then smear some high temperature black gasket maker (in a tube) over the area and pray it works.