I have an 2000 400ex with a .40 overbore and has a fmf slip on with stock headder pipe has all new swing arm, axel , hi performance stator, hi performance coil and cap, and a rev box cdi... The new parts have jus been put on maybe 10 to 15 rides ago and now she will not go I got a buddy of mine over and there's a lot more wrong then I thought my swing arm moves on the axel my second jet the head got snapped off in the carb and there's some type of leak where the head meats the motor... How much as is right now

 

Prices are regional. In the North East depending on esthetics and how tight the rest of the ex is you are looking at 500-800. Prices for a older turn key ex start at 1100-1200 around here.