cr 500

[timmy400exfast]

k i know theres a guy on here who has done this conversion but i dont rermber his name if anyone knows anything bout this build it would be helpful i am most like gonna do a cr500 400ex build here are my q's
is it really that hard of a build?
are the vibrations as bad as evryone says?
what do you do about the problem with the intake boot?

[00.400ex#55]

If you don't like working on bikes then don't bother. I put in a few hours a week to make sure things are tight and ready to go. Well, you should with any bike but it's much more important on a cr500. So far this year I have only broke 1 thing, which was my front exaust mount. I had a lock on it ( a socket cut and welded to a tab with another bolt and lock nut ) and intead of the nut backing out it eventauly just stripped the threads. I replaced it with a 30mm long coupler nut so it wont happen again.

From what I have seen, rubber mounts only seem to make things worse. When you look at a dirtbike frame the are very tight to the moter and very stiff. An atv frame is small tubing and very open. It seems simple to me, Make your frame stiff as ****!! A good idea is to add vertical cross bars to the upper and lower frame rails. This stiffens the frame alot and cuts down on vibration tremendously. If you do it this way, you can use a cr500 pipe and not have to cut it anywhere!


This is where I started, I cut out the old mounts and sat everything in the frame. It fit quite well.

http://i203.photobucket.com/albums/aa289/quadracer56/DSC00289.jpg

http://i203.photobucket.com/albums/aa289/quadracer56/DSC00299.jpg


I welded in some crass peices for the vertical tubes and an X brace for the lower mounts. Pic with one side done. They are removable aswell which makes everything much easier.


http://i203.photobucket.com/albums/aa289/quadracer56/DSC00329.jpg


This is where the front mounts get welded too. Notice the clearance is very minimal to keep it as ridged as possible.


http://i203.photobucket.com/albums/aa289/quadracer56/DSC00336.jpg

[00.400ex#55]

The silencer had to be cut and turned to bring it down. I ran it inside the sub frame.

http://i203.photobucket.com/albums/aa289/quadracer56/DSC00331.jpg


I made these in my machine shop class, They connect the vertical tubes to the existing frame. Nice and stiff!

http://i203.photobucket.com/albums/aa289/quadracer56/DSC00517.jpg


Sorry thats really all the pics I have of the build. Some other info:

Radiator is a yfz, it fits great and has kept the engine cool with some regular car coolant.

Intake is a 2.5 inch alluminium tube and the air filter is a k&n part number RU-1770. You have to cut a huge notch for the intake though, I made up for it with some more tubing underneath which you can see in the pics bellow. I made a coller that goes around the filleter which is welded to the frame. The fiter slides through it.

Make you sure you pay attention to the pipe when fitting, Mine was touching the radiator hose on the cylinder and I had to put a little indent in my pipe.

You may need a high flow fuel valve, I bought a pingle to handle the long open straights. Don't buy the one that says it fits both 450r and 400ex, it dosn't and youl have to enlarge the holes.

Hmmm, thats about all I can think of. If you need any help just send me a message anytime.

[00.400ex#55]

http://i203.photobucket.com/albums/aa289/quadracer56/P4270065.jpg

http://i203.photobucket.com/albums/aa289/quadracer56/P4270064.jpg

http://i203.photobucket.com/albums/aa289/quadracer56/P4270060.jpg

http://i203.photobucket.com/albums/aa289/quadracer56/P4270057.jpg

[00.400ex#55]

How it sits completed, and with the a-arms I made.

http://i203.photobucket.com/albums/aa289/quadracer56/DSC00541.jpg

http://i203.photobucket.com/albums/aa289/quadracer56/DSC00536.jpg


First time start up, There are no tie rods on it so ignore the front wheels.

http://i203.photobucket.com/albums/aa289/quadracer56/th_P4290069.jpg (http://s203.photobucket.com/albums/aa289/quadracer56/?action=view&current=P4290069.flv)


http://i203.photobucket.com/albums/aa289/quadracer56/th_P5100084.jpg (http://s203.photobucket.com/albums/aa289/quadracer56/?action=view&current=P5100084.flv)

[timmy400exfast]

dude ive been looking at pics of your quad and it looks sick i have a bunch of time on my hands and got money to do it will be saving up for a lil bit though i love working with motors also is it that hard of a build if you have the time?

[00.400ex#55]

Its really not that hard if you're a good welder/fabricator. It does take a good amount of time to get it all done. There will be quite a bit of trial and error, but eventualy you will get everything worked out. Don't give up the first time, mine has been 3 years in the making. For me it's deffinatly worth it, a 450 feels like dog **** compared to this. I could never go back to one. I can't help but luagh at it while im riding one. A few hours maintenace and some repaire once and a while is well worth it. Even if I have to tear it all down in the winter (which I always do anyways) and fix any little cracks, I don't mind. It gets a huge amount of attention too. Everyone is always saying "WTF is that?" I love it!!!

Also, these motors are bomb proof! I have sucked in water, ran it way to lean, ran with bad crank seals, and I rarely use the clutch to shift up or down. Still on the same piston as I was last year when I had a 250r pipe and a 44mm snowmobile carb that kept running dry.

[timmy400exfast]

dude your qaud is the sickest qaud on here love the colr scheme i was i am willing to put some time in it but i am also doing a mustang stroker project so i am gonna be contiplating wich is more inportant i wanna do this cuz every1 around here with a 450 or raptor thinks there **** odnt stink.................................ps have you dynoed it

[matt14c]

To help with the vibration a guy around here had his frame injected with some sort of foam. He put a CR250 motor in a ex frame. Not sure what kind of foam or how it was done but just an idea I guess to think about for your project. Good luck if you do and keep us updated!

[00.400ex#55]

When I first built it with a 250r pipe and a ****ty carb it made 43hp and 62ft-lbs. It is deffinatly faster now but I have not had it dyno'd. It makes at least 50hp and probly 65ft-lbs.

Heres the sheet from a while back. Look at that air-fuel ratio... Its everywhere. My bike was the first on that dyno, he didn't know what he was doing! I said **** it and bought a stock carb for it, runs like a champ.

http://i203.photobucket.com/albums/aa289/quadracer56/P1010022.jpg

[timmy400exfast]

maybe ill try that ill keep you guys posted maybe be pulling the motor on my ex late agust september then possibly be selling parts for $$$ to get the motor

[timmy400exfast]

dude this is gonna be a awsome build

[416exman21]

that thing is tight --- i want to do that to my 416 but i already have a zilla-----now you can be on the 500 2stroke level----i had a cr500 dirtbike when i was 15 and sold it last year ---holy **** that thing was a rocketship-----