CDI Question

[yernkie]

I've heard people talk about using a CDI off of a ??? on a 400EX. The CDI in question is supposed to be a factory Honda part off of a four stroke dirt bike (I think). I am heading up to a Honda shop to pick up some parts in 30 minutes and I was wondering if anyone knows what part I need and the advantages/disadvantages.

the only thing that i could think of is a xr400 that has same motor put a little more hp

[GPracer2500]

Pretty sure it's the XR250 CDI. It has a higher rev limit and more ign advance.