I need some help. I want to rebuild my 02 400i cat. I believe its the last year for the liquid cooled motor in the 400...but i am probably wrong. I have a K&N, jet kit, hmf penland pipe, and a pre filter....but i want more power. I got such a good deal on the bike that it is alot cheaper to redo the motor than to upgrade to a bigger bike. I have read alot about the 581 kit but no where could i find if it is actually for a 400. Does anyone know of a way to get more power out of a 400? If not...where can I get a 500 motor...i think they will bolt in. Any help is always greatly appreciated.