Picked up a 2003 400EX with an XR650R engine.

[Blown 331]

I already have an XR650R, only liquid cooled XR ever and only aluminum frame XR ever, and now I have a quad to match! I only test rode it before I picked it up, it's still on back of my truck. It has a ton of power and a real clean install. I also got a hot cam, spare bottom end and a bunch of other parts. It has Looney Tune true dual exhaust which was supposed to be $800. It supposedly beats Banshees, 450s and a Cam Am 800, we'll see! Either way, I absolutely love it so far. First thing on the to do list is front fenders, I hate race cuts, had to get fenders for my Banshee too.
http://i1041.photobucket.com/albums/b411/Blown_331/20141110_182258_zps8rqyryyl.jpg (http://s1041.photobucket.com/user/Blown_331/media/20141110_182258_zps8rqyryyl.jpg.html)

[YTZ drew]

sweet! enjoy it!

[oldskool83]

they cut the fenders cuz the radaitors, your just gonna waste money on new fenders you gonna have to cut up anyway. A real trike rider does not need fenders on a ATV because you cant see where the where is!

[Blown 331]

Well I hate race cuts so its getting fenders. I don't care if I have to move the oil tank up front and use a TRX450R radiator. I don't think it will come to that and the conversion is so clean I'd hate to mess with it. I think fenders will fit with the radiators. My cousin has a spare set, I'll will try to get a hold of those. And if minor cutting is needed, so be it. It will still look way better than it does now.

[IKE-Z]

If my memory serves me right you helped a fellow member get a sweet Tri-z. Here's some good karma coming back to you. That looks like neat addition to your toys!

[rdonald1979]

You should do the quad rad anyway. Just a little more cooling.

[deathman53]

defintely use the trx450r radiator, the stock xr650r radiators can barely cool it in the dirtbike form. Throw 2 high traction wheels and the slower speed atv's go at times and it heat rises fast. My crf450r is trx250r does run kinda hot, especially when slow riding. Put a larger motor in there and watch the heat go up.

[Blown 331]

I've never heard of 650R cooling issues and I have one. I'll research it. No matter.
http://i1041.photobucket.com/albums/b411/Blown_331/20141213_173532_zpskle7ojhi.jpg (http://s1041.photobucket.com/user/Blown_331/media/20141213_173532_zpskle7ojhi.jpg.html)

[SteveCZ28]

looks way better with the full fender on it

[Blown 331]

Thanks and I couldn't agree more! I hate race cuts. I had to buy front fenders for my Banshee as well, seems like 75% are cut. Crazy.

[NeverLift]

Ride report yet? Thing looks great. It's been a dream of mine to build one of these.

[oscarmayer]

Looks like a very nice setup. Are you gonna upgrade the suspension? I am thinking that with that much more power, it would make sense to upgrade the suspension and set it up with nicer stuff.

[Blown 331]

I have not raced it yet but it would not surprise me if it is the fastest ATV I own. The power and torque are unbelievable, even leaning up over the handlebars, it will lift the front end with just throttle in 3rd gear. Seems like it would actually be kind of difficult to race. Well if you ease into it you can keep the front end down. The stock carburetor is a round the slide with no accelerator pump I have an FCR from a 2006 Honda 450 I'm going to try on it one of these days. I absolutely love this thing it's definitely one of my favorite. suspension had actually not crossed my mind. These things handle pretty decent I think. If I was going to buy any suspension it would probably be for the banshee.


]http://i1041.photobucket.com/albums/b411/Blown_331/20141213_212613_zpsgwfdyqkg.jpg (http://s1041.photobucket.com/user/Blown_331/media/20141213_212613_zpsgwfdyqkg.jpg.html)

[nd4speed]

that's a really cool conversion...I like it a lot.

So if a 400ex motor goes in a 350x without much problem and a xr650 motor goes in a 400ex then...? The liquid cooling probably doesnt fit anywhere except on the triples like the first gen Tecate.

[oscarmayer]

^ we are always stuffing 2-smokers into 4-stroker frames, don;t be so quick to judge. i stuffed a 450r into a rapy 125 frame w/o any problems or issues. just FYI. this has the rad on the side. Me, I would look at putting in a 2011 YFZ450R rad into it. a racing alloy one off ebay is shipped for $90. pretty cheap and ensures you never have an issue,

[Blown 331]

One of the first ATC450Rs I ever saw was a 350X with CRF450 engine. It had the radiators mounted in the same location you'd normally see them on a dirt bike or ATC250R. The stock 350X shrouds would not fit though. Perhaps a whole 650R gas tank and shrouds could be used?
My cousin put an XR650L engine in a 350X. The 650L and 650R basically share nothing in common. The 650L is air cooled. That engine was too tall to fit in a 350X frame so he grafted the whole engine cradle out of the 650L into the 350X frame. That would not be possible with the 650R frame since it is aluminum. So I'd say you'd have to cut the engine cradle out of the 350X frame and make your own. Getting radiators on a 350X frame shouldn't be too hard but getting shrouds over them could take a little work. I did see a pic of an whole XR650R converted to a 3 wheeler. It basically just the dirt bike with an ATV swing arm and 3-wheeler front end, it was rideable but needed a lot of work yet in my opinion.
And from what I could find unless you are running the lean stock jetting theres really no overheating issues with the stock radiators. They are quite huge, bigger than the MX bikes. In my opinion the XR650R is just in a league of its own, nothing else like it.

[oldskool83]

suspension and chassis upgrades get costly quick is not your not keeping it don't do it. a plus 2 swinger would prob be better idea if you want to keep the front end down.

[Blown 331]

This is definitely a keeper but I'm still not really planning on suspension modifications. Swingarm maybe something to consider but that would be about it.

[SteveCZ28]

after seeing the side pic with the ful front fenders on it again, it looks sweet. most people wouldnt notice that motor in there, so it just looks like another every day 400ex. but those that have the trained eye will notice it. id love to have one of these. looks like a blast