i just looked on fourstroketechs website and i saw that kit. Has anyone done this kit?

 

There is a kit on www.motosport.com for the 400ex too. Look under the engine/crank section. It is a Hot Rod crank kit.

/Jon

 

By the way, I should have mentioned that you couldn't find a more reputable builder if you choose to have Mickey install the kit he sells.

/Jon

 

Well i have the kit and i have to say very fast very very fast in the top end u have to do alot of head work and port and polish the problem i am haing is that the head cannot handle the stroke so i have to have it ported and reworked and tweaked.or you will be smoked bye a 416 kit