Have an 05 400ex, the cylinder should be back next week. Bored to an 86mm with a 10:1 wiseco piston kit. I am running a full Yoshimura exhaust, no air box mods, just the clamp on moose filter.

I am curious what other people run for jetting and cams on a 10:1 set up.

 

Jetsrus has a jet kit for this model that has aftermarket parts.Cheaper and less frustrating than ordering one or two at a time.https://www.jetsrus.com/a_jet_kit_at..._1999-2008.htm

 

Web Racing Cams did a great job grinding a cam for my old Arctic Cat 500, I also put in a 5 degree timing advance key and K&N filter. Dynojet Stage 1 kit got me perfect. You have to tell the cam grinder what you are looking for. The cam they did for me made it a stump puller, yet it still turned all the way to 8,500.