ATV Florida Forum

Ive been talking about a cr500 or cr250 conversion in my 400ex for a long time now, just recently I found a 98 cr250 and the guy only wanted $500 for it.

So now the project begins!!

The 400ex motor is said to be around 31hp stock, the cr250 45hp stock, I know theres extra weight involved but a stock 45hp in a atv should still be around 40hp.

With my 440, big carb, cam, timing and other mods I think Im only pushing 40hp anyway. So with a cr stock pushing 45ish HP, after I add some drag pipe, high comp, timing, reeds. etc... 

I think this will be a big improvement on DFA's 300ft drag strip 8) It will also improve my 8th mile time 8)

Currently it starts right up and runs, it may need a rebuild, it will deffinetly need tuned again, but it doesnt look to beat up, I feel that I got a sweet deal on this thing.

Let the tear down and fabrication begin 8)

What do you guys think? Any experience with modding these 250rs? Whats a good starting point on modding these motors and where and who is a quality shop in FL?

the weight difference between the 2 motors is said that the cr250 motor weighs 25lbs less then the 400ex motor also

If you're looking for a builder. RTR is legendary with the 250R motors. He built our blaster and it went from back of pack to top 3 in points in our class. Rick is a pleasure to deal with as well! Check his site and give him a call tell him what you looking to do.


Or just bring it to DirtyFOot this weekend, he will be there and you could run the dragstrip!

check out the progress!!!    I need to get some bushings/spacers made and I have to grind the swinger bolt hole on the motor to get the sprokets to line up, possibly even use some washers to space my rear sproket a lil bit.

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/Workandplay061.jpg)

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/Workandplay062.jpg)

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/Workandplay064.jpg)

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/Workandplay063.jpg)

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/Workandplay065.jpg)

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/Workandplay061.jpg)

The 400ex rolling chassis weighs right at 200 lbs, the 400ex motor weighed 100 lbs, the cr 250 motor weighs 50lbs!

This is gonna weigh around 260lbs when Im done.

Is that kicker going to clear the frame?

cool project but something you should consider is that you really shouldn't use a motor out of a bike in a 4 wheeler. atv engines have counter balancers for a reason. using a cr 250 top end is a good idea but you really want a trx case. your gonna need to buy red lock tight by the 50 gallon drum. good luck with it.

I was hoping to see the video but I guess you just gave us the ending :Clap.gif

Updates!!!!!!!!!  Fabbed up some stuff!!!!!! Got my FTZ drag pipe!

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb002.jpg)
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb003.jpg)
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb009.jpg)
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb005.jpg)
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb007.jpg)
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/blandish005.jpg)
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/blandish007.jpg)
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/blandish009.jpg)
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/blandish008.jpg)

The kicker needs a 3 in extension and is pre made like everything else, Im getting everything welded like the kicker extension, pipe and top motor mount the week after xmas andnbefore new years, hopefully I can be at DFAs drag races for new years weekend!

I just wanna get it all together and running, then later get the motor work, re painting, custom subframe and possibly custom a-arms in the very near future.

Are you kidding me?

Well its almost done!

All I have to do is put the kicker on and put some new fluids in it, Ill be test riding it this weekend.  8)

Here's the progress pic's!

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/workandquad045.jpg)

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/workandquad046.jpg)

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/workandquad052.jpg)

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/workandquad051.jpg)

that thing is going to be sick! Screw the negative morons on here! Ive seen a few bike conversions from here to cali. people dont like anything thats not built in a factory. f'em, I love it. hope you finish it and post some vids. :o ;) 8)

Actually, I rode it this saturday! And I got a VID!   lol.

It rips way harder then the EX motor did, with drag slicks and dirt roads this thing pulls HARD!

The vid isnt that great, I start the vid try to kick it, mess with the carb, then start it and ride off, a few mins later I come back.

But heres the vid anyway, time to take it all apart and re-paint, Grease and loctite everything.

Then Ill be at DFA for the 300ft test ;)

http://s953.photobucket.com/albums/ae15/johndoe83_2010/?action=view&current=SUNP0154.mp4 (http://s953.photobucket.com/albums/ae15/johndoe83_2010/?action=view&current=SUNP0154.mp4)

Here's some updated info on the hybrid project, Ive had some seat time and this thing has far exceeded my expectation's. It starts right up, idle's good and haul's butt. I made a custom hood to cover up the radiator and create a hood scoop to force air at the rad but it looks like a mailbox...lol.

I tried to make it look like a 250r or 250ex headlight but its kinda bigg, I also took my stickers off the plastic and mounted the silencer to make it more quiet. I took the drag bars off and put my low rise bars with a new foam honda pad on, I took off the rear shock setup and put my drag strut on.

It really ride's great!

Here's some pic's and some video of it running, let me know what you think about the hood "I know it's kinda big" but I want more opinions, let me know if you want a more detailed pic of something else also?

(http://i953.photobucket.com/albums/ae15/johndoe83_2010/SUNP0160.jpg)
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/SUNP0159.jpg)
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/SUNP0161.jpg)
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/SUNP0162.jpg)


Here's the video!

walk around
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/th_SUNP0157.jpg) (http://s953.photobucket.com/albums/ae15/johndoe83_2010/?action=view&current=SUNP0157.mp4)


riding and at the end heat temp reading.
(http://i953.photobucket.com/albums/ae15/johndoe83_2010/th_SUNP0158.jpg) (http://s953.photobucket.com/albums/ae15/johndoe83_2010/?action=view&current=SUNP0158.mp4)





Here is a link to the build thread


http://www.exriders.com/vbb/showthread.php?s=&threadid=477981&highlight=hybrid (http://www.exriders.com/vbb/showthread.php?s=&threadid=477981&highlight=hybrid)

Probably feels awesome to ride your own creation.. Nice job. Not sure if I like the height of the scoop.

Looks pretty nice man. I remember several years ago there was a build on here with a cannondale frame and a cr500r motor. Thing was sick