It doesn't have to be removed, but I agree with JK, it would be a lot easier to take it out. Since Honda changed to the longitudinally mounted engines, most of the time it's easier to just remove the engine if you have to remove either the front or rear crankcase cover. If you don't, you don't have much room to work in.
Most 4-wheeler problems are caused by a loose nut connecting the handlebars and the seat!!
You only need two tools in life -- WD-40 and duct tape. If it doesn't move and should, use the WD-40. If it shouldn't move and does, use the duct tape.