I've been researching that as i am thinking about building up a 400ex, so nobody has actually put a xr600-650 motor in a 400ex frame on here?

 

dirtwheels made a quad like that awhile ago they called it the 600ex. it was extremely fast. me and a buddy put together a 400ex and we decided a cr500 motor would be a little bit funner than a 400

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Honda TRX450R - LRD stage one kit, fastest bike around havent been beat in a drag yet

 

I think like 5 years ago, dirtwheels put a xr 400, or xr650 engine in a 300ex, I think it was before the 400ex was a quad, but dont quote me, I am not sure.

 

Looks like im not the only one that wants to put an xr650 motor in a 400ex. DAMN COPYCATS!

 

Hopefully, you will be able to buy one off a dealers floor, sometime soon!

 

lol sorry, i like how light and agile a 400ex is, but after riding my ds, it feels soooooo slow,