I have a chance to get a real nice set of nerf bars fro a great price.thay came off of a 2004 honda 400ex.Will these bolt right up to my 2007 400ex.

 

They should

 

I know that 2004 is the different gen from the 2007, but I think the plastics were the only real change, which should still alow you to fit 2007 nerf bars on a 2004. If its a great deal, then I would go ahead and buy them, and if worst comes to worst, you can always resell them if they don't fit. But I bet you dollars to donuts that they will fit. Let us know if you get them and if they do fit!

 

Looked at a catalog for AC Racing nerfs. One size covered 99-08 year models. Sounds like your gonna be getting some nerfs.