400ex/cr250r hybrid? Maybe? yes.

[JOHNDOE83]

Well its been a goal of mine to do a cr250 or cr500 swap into my 400ex drag bike. I recently found a 99 cr250 for $500, in good running condition and might go get it tomorrow!

I have a metal fab shop that will do the work almost free of charge and has a good reputation.

I did a lil bit of research and its said that the cr250r motor has 45 HP and is 20+ lbs lighter then the EX motor, which if this is true will make this thing fly down the 300ft or 1/8th mile!

I dont care about vibration and things like that. "its a drag bike"

Does anyone have any issues with this idea or know what others have done with cr250r motors?



http://i953.photobucket.com/albums/ae15/johndoe83_2010/dragraces008.jpg

[Zakradu398]

http://www.servicehonda.com/honda-2010-models/atv-srx250r

[JOHNDOE83]

Originally posted by Zakradu398
http://www.servicehonda.com/honda-2010-models/atv-srx250r

Yup thats what Im building:D

[Zakradu398]

That would be sick, but now I'm selling my 400 to get a banshee and stroke/ port it.

[JOHNDOE83]

The project has started.


http://i953.photobucket.com/albums/ae15/johndoe83_2010/Workandplay051.jpg

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

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


So far the swinger bolt hole in the motor is to big for the 400ex swinger bolt, Im going in a few hours to drop off the stuff to have a bushing made.

Then I can see if the sprokets line up right or if I need some grinding or shiming... maybe both?

The stock ex motor mounts almost work, they could be shaped to fit or I could get new ones made, maybe Ill try to get new ones made instead of heating and bending the stock mounts.

The top motor mount and the mount under the motor will have to be made.

A pipe and a kick starter will also need to be made, I think 250r pipes work, One guy had to cut a 1in section out to clear his tie rods. Im hoping to find a out of frame 250r pipe to avoid issues.

[JOHNDOE83]

The 400ex motor weighed 100lbs, the cr250r motor weighed 50lbs!!!

The chassis with no motor weighs almost exactly 200lbs.

With the drag cut plastics and that CR motor with components this quad will weigh around 260lbs, with drag struts you can take a extra 20lbs off that also.

[sand_blaster]

Exciting project, keep up the good work.

[HondaPohl]

All hail the 2 stroke!!!!!!!! I went four stroke but its good to be back with the smokers. Should be nice. Just watch vibration.

[JOHNDOE83]

Heres a Update!!!!!!



http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb001.jpg
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/exfabb004.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb006.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb005.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb011.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb012.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb013.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb008.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb010.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb015.jpg



And this is where it all happend...LOL.

http://i953.photobucket.com/albums/ae15/johndoe83_2010/exfabb014.jpg

[MisterGraphic]

Nice project,
Keep up the good work!

[mirror_racing]

Looks sweet. Can't wait to see more!

[SRH]

that bottom motor mount is not going to do the job, you need to put a cross tube with tabs

we had a 400ex with a 2001 cr 250 engine...very dissappointing, the pipe is the main issue...but really the gearing of the engine combined with 2 stroke characteristics...it wasnt a fun quad

[SRH]

airbox is off a 85-86 atc 250r , we used a 4 trax pipe...really needs the dirtbike one but you run into some interference with frame rails... guy here did a 500 ...should be able to find the thread where he got it to work by making a moveable frame rail

[JOHNDOE83]

Check out the progress



http://i953.photobucket.com/albums/ae15/johndoe83_2010/blandish008.jpghttp://i953.photobucket.com/albums/ae15/johndoe83_2010/blandish007.jpghttp://i953.photobucket.com/albums/ae15/johndoe83_2010/blandish009.jpg



This is the difference between a cr250 gnarly pipe expansion chamber compared to the ftz drag pipe chamber.


http://i953.photobucket.com/albums/ae15/johndoe83_2010/blandish004.jpg


Those bottom mounts dont do anything to hold the motor in place, they are just there for stability so they are fine like that.

Im gonna run open filter with no airbox but using the atc airbox would have been a great idea!

This is gonna be a WOT quad only so the 5 speed gearing and 2 stroke charecteristics are gonna work in my favor for this specific build.

Im gonna change my kicker assembly a lil bit, Im gonna run a xr80 kicker now!

[Chukkinsod]

your on the right path... looks like you are making great progress....will it see a big bor stoker in the near future????? Thought about doing the same only with an R based motor>> keep me informed

[ytman]

Cool. Where'd the radiator go ? Or maybe where's it gonna go ?

[JOHNDOE83]

Originally posted by Chukkinsod
your on the right path... looks like you are making great progress....will it see a big bor stoker in the near future????? Thought about doing the same only with an R based motor>> keep me informed

It will deff see a big bore, im gonna wait till the stock rod goes before i do a stroker crank.

[JOHNDOE83]

Originally posted by ytman
Cool. Where'd the radiator go ? Or maybe where's it gonna go ?

Im using the stock cr radiator, so far I think its going above the front grab bar area.

Im gonna find out tomorrow!

[JOHNDOE83]

Well I got the top motor mount, kick starter and pipe welded up!

Unfortunatly when I was marking and drilling the mount for the top of the motor, I somehow drilled the hole for the right frame mounting bolt "alot" of center :rolleyes: like almost 1/4 inch.

Its the only mistake so far and its not horrible but now I have to settle for a wobbled out of center hole, But its a good steel mount so its cool. :ermm:

Atleast now I can put it all together and put the plastics on and re fluid the motor, the only thing left after that is to bend a new stinger to silencer mid pipe.

Maybe I can test ride it this weekend?

I will have new update pics friday night!

[JOHNDOE83]

Well I got alot of progress done today, but was only able to get a few pics.

At the end of the day I had the carb, electronics, radiator and all sorts of other stuff done...just didnt stop and take to many pics, sorry guys. Atleast now you know by the next time I post pics it will be essentially done.

I discovered the throttle cable for the cr was bad so I have to get a new one of those, Im using a 1985 cr80 radiator instead of the 250 rad, its smaller but thicker and the way the hoses are routed on the 80 rad make a better fit.

I also discovered that 400ex sprokets fit the cr sproket shaft and it made the sproket allignment perfect, so I stepped up the 13t to a 14t.

AND, If your chain slider is getting worn, you can grind it back smooth and get more usage out of it! So I did that to.

Heres the pics...

http://i953.photobucket.com/albums/ae15/johndoe83_2010/newzies013.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/newzies014.jpg


CR 80 Radiator and where its going.


http://i953.photobucket.com/albums/ae15/johndoe83_2010/newzies010.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/newzies011.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/newzies012.jpg



Top motor mount....



http://i953.photobucket.com/albums/ae15/johndoe83_2010/newzies007.jpg


pipe welded and put into place, I got to find some smaller springs to make it fit perfectly into the head.



http://i953.photobucket.com/albums/ae15/johndoe83_2010/newzies006.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/newzies009.jpg.

[JOHNDOE83]

Here is a lil bit of progress, will be done soon.


http://i953.photobucket.com/albums/ae15/johndoe83_2010/workandquad052.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/workandquad051.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/workandquad050.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/workandquad046.jpg
http://i953.photobucket.com/albums/ae15/johndoe83_2010/workandquad045.jpg

[JOHNDOE83]

Mine starts and rides:D THIS THING RIPS!!!

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

[711stretfighter]

LOL Man that thing is loud!!!! Gotta get some riding video too.

[03trx400]

I agree with 711! Looks and sounds good, how's it compare to the old 400?

[JOHNDOE83]

In comparison to the 400ex motor this is Alot faster, it was spining those 18s alot more then the ex motor did, even with the slicks on a dirt road this thing pulls HARD!!!

I can only imagine how fast its gonna be when its hookin up, the pipe makes the powerband so NICE, it easily added 5-10hp over the gnarly pipe and this is noticeable even after switching it to the quad frame.

Im gonna start tearing it apart in the next week to grind some tabs off the frame and re paint and re grease eveything and add loctite.

[Zakradu398]

I need one of these

[03trx400]

Originally posted by JOHNDOE83
In comparison to the 400ex motor this is Alot faster, it was spining those 18s alot more then the ex motor did, even with the slicks on a dirt road this thing pulls HARD!!!

I can only imagine how fast its gonna be when its hookin up, the pipe makes the powerband so NICE, it easily added 5-10hp over the gnarly pipe and this is noticeable even after switching it to the quad frame.

Im gonna start tearing it apart in the next week to grind some tabs off the frame and re paint and re grease eveything and add loctite.

Good to hear! Definitely wishing mine was at the same point but still waiting on the radiator. Have you taken any more vids? Would like to see that thing in action!

[JOHNDOE83]

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

[tayyo789]

To fix the look of the scoop, make it lower in the back, and longer overall, to hide the hole in your plastic from view. Personally, I would make it smaller altogether to match the aftermarket type hoods, and then put some small scoops behind the shocks that push air up into the radiator. Much more subtle of a look

[JOHNDOE83]

Ya I think im gonna buy a 250r hood and cut it short to make it fit right over that hole in the plastic so that the opening is right at the rad.