I know this question has probably been beat to death but I have searched and have not really seen the answer I have been looking for. I just got a brand new 05 400ex and was wandering what some of the first upgrades you would make to pep it up a litle bit. Getting ready to change to oil for the first time and plan on putting Amsoil 4-stroke oil in it. Hey guys thanks for the help and ideas.

 

Full exhaust, Pro-design Intake with high flow filter and rejet. Best place to start [img]i/expressions/face-icon-small-happy.gif[/img]

 

i like what i have in mine it gave it good power

 

440 kit will give some power, but will void any kind of warantee. plus a lot of times it makes them less reliable. just the basics to start. exhaust(i love my yoshimura TRC, great sound and performance increase), intake and jet kit. then talk to us from there if you need any more

 

Get a pipe and filter for now, itll tide you over till you need a 440 kit.