I have a friend that has a 03 400 EX that is currently a very good running 440 but he wants more so...Has anyone put a XR 650 motor in a 400 EX frame and if so how difficult was it?Any 300 foot times on a EX with a XR 650 motor?How about some pictures.Thanks for any responses.

 

This was done a lot in the past. One of them raced one of the big desert races (Vegas to Reno as I recall.....it didn't win), but I haven't heard of it much since the 450R came out.

 

ive done it and its awesome . go to my profile and there are some pics. thanks mike

 

But.....when a CRF450X is as fast as a XR650, what is there to be gained unless you are just looking for a project???? The whole idea of the 450 class of engines is to do more with less.........

 

It's probably a hell of a lot easier to pick up a used XR650 engine than it is to get a fairly new (I'm presuming) CRF450X engine. Though the weight advantages might be worth it ...

 

the xr650 in a 400ex is an awesome and different dune quad and it will smoke any 450 in the dunes. thats what i built mine for and it handles great too.

 

If you want a "different" quad ... look at XR650Warrior's machine. Same mod concept done on a warrior .. pretty sweet actually ..

 

I have a 400ex conversion done now with a xr650L as well, there is one pic of it on my page, just a motor view though, my other pics were too big to load at this time, other pics of it have been floating around on other sites, it ran 4.6's first time out in a raw state without any tuning, times are now getting better.[img]i/expressions/face-icon-small-smile.gif[/img]

 

Got a couple more pics of 650ex loaded on my page now, should be approved soon

 

4.6 is really moving.I will pass this information on.Thanks.