Im thinking about installing an xr650 dirtbike motor in my 400ex chassis but im not sure if it will fit. I have seen 400ex's with xr600 motors and they fit but I dont want a kickstart. So my question is: will an xr650 motor and carb fit in a 400ex chassis? will i have to make custom headers? will my kehin 41mm carb fit an xr650 motor?

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Ive seen one in a 400ex frame before, it worked for them, but you may need to do some fabricating.

 

I really dont want to cut into the frame at all but fabricating some new brackets would be no problem. Do you know of any websites where I could view some 400ex's with this setup?

 

I dont think you will have to do anything to the frame (hopefully), but im about sure you will have to make some mounting brackets for it. Its been so long since ive seen that video that i have no idea what site it was at. You may want to try exriders.com, other than that, i have no idea, sorry.

 

only fabrication you may possible need is grinding down the frame and fill welding the holes or just make some custom engine mounts.

 

ive seen one on sandbros.com guy built it for desert racing.

 

Other frame work you'll probably need to do is to make some gusset braces to strengthen the fram to handle the high horse power. You'd be wise to strengthen every joint.

 

Thanks for the info, Im seriously contemplating doing an engine swap this winter, would it be worth it? how much hp does the xr650 motor make stock and are aftermarket parts readily available?

HA2, I checked out that website and I couldnt find the quad you were talking about unless you were talking about the 650ex with the weird rear suspension, could you give me a link?

 

A XR650 MOTOR HAS THE SAME MOUNTS AS A 4OOEX. I BUILT A XR650 THREE WHEELER. ITS REALLY FAST. IT SMOKES MY QUAD AT GLAMIS. I HAVE A 04 400 WITH A CAM REV BOX, EXHAust, intake and an edelbrock carb. i used the xr650 frame, forks from an xr600 200x triple clamps and 200x axle. i made the rear sub frame and swing arm. works perfect looks like it was made from honda. i`ll post pictures of it soon