I need to know how i can get better top end in my 2000 400ex im gettin a pipe but what are some cheap ways to get top end and cna u tell me bore sizes of pistons and what cc's they are

 

Open up the air box (free), get a UNI filter or equivilant ($20) and add a couple more pounds of air in the tires (free). After that you will have to re-jet ($10+/- assuming you do it yourself). Make sure jetting is perfect! Next, you can add a 16 tooth front sprocket cheap ($10-25). Be advised....unless you go inside the engine with big bore kits, cams, porting, etc. you'll only pick up a bit of top speed. Tough to get top speed cheap.