elevation

[hemi400ex]

i ride from 380-1500 ft above sea level here in WV/PA can any one help with what jets i can run so no matter where i ride i won't have to change them, putting on a k&n air filter, and a full exhaust system at the same time, and should i go with dyno jet, or keihin for my jets

[zrpilot]

I'd jet it for the middle elevation.

Stick with keihen jets..

[hornetgod13]

Is your airbox lid going to be on or off? What is temperature range that you ride in. Those are additional factors that will effect your jet selection. When the temperature drops 30 to 40 degrees you might have to bump up the main jet one size.
I would stay with keihin jets. They are easy to track, same brand as stock, and you won't need to buy a kit with a bunch of unwanted sizes.
www.jetsrus.com carries all keihin jet sizes for the 400ex.

[hemi400ex]

air box lid on, alot of dust, water, and mud, temp range is around 40 and up, would 155 main, 42 pilot, leave needle alone, hmf sport slip on, K&N filter, and K&N filter cover be a good start?

[hornetgod13]

With the airbox lid on 152K, 155K or 158K should be what you'll need.
The 40K or 42K pilot would be great as well. It will make cold weather starting a breeze.