I'm wondering how hard it would be to put an xr600 or xr650 motor in a 400ex? If possible would it be worth the conversion. Mostly I'm just curious & I'm not really considering it yet. I'd appreciate some indepth comments. I'm really not that familiar with the 600 or 650 motor. Would it be a improvement or not. How much fabricastion would it involve? What do you all think? Thanks

 

I've seen that it's been done successfully but on a strong budget of course.

If you have to ask on an internet forum how hard it would be to swap engines, i have my doubts in how successful your venture will be.

why not just buy a 450R or a YFZ or a Raptor?

 

It just crossed my mind at the office. So I fugured this would be a place to start. Is the xr650 a good engine & would it work well in a 400. I'd be paying my wrench to do it as it is definately more than I could do at this point. Realistically its probably not going to happen. Just curious as to what people thought of the swap

 

You would also have to think about setting up the motor for a four wheeled quad. It's not the same as a bike. Would be a very interesting project and would cost major lute to do it right.

 

what do you mean "set it up"? are you talking about gearing, flywheel weight, ect.? Or the lining up of sprockets and leveling of the engine?

I've put an RM250 motor in an LT250R which I would say is probably roughly as extensive of a swap as an XR650 in a 400EX...

electronics, exhaust, ect... not that big of a deal as long as you've got a parts bike handy.

Money always help. Throw money at it.