CR250F in a 250X/300EX

[jonboy]

I've got this idea in my head and am liking it more and more. I am wondering if anyone has done this setup, and if so what are the in and outs of getting it done. I know that it'll be a little torque monster and will probably make a great TT bike. What do you guy think?

[jonboy]

Wow! Nobody? That sucks.:confused:

[TheNewn]

I think it would be a perfect Hybrid. a 250F is a killer motor, putting out like twice the horsepower of a 300EX.

If i had the money and bikes i'd do it in a heart beat. It would be great. I'd love to see your progress of it if you choose to do it.

[250Renvy]

Here's a brand new motor

http://cgi.ebay.com/ebaymotors/2006-HONDA-CRF250-CRF-250-CRF250R-ENGINE-MOTOR-KART_W0QQitemZ150186955194QQihZ005QQcategoryZ35595 QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[400ex4ever]

I have done business with Keep it Roostin several times. I highly recommend him. What you see is what you will get.

[TheNewn]

If i were you i'd try my best to get a CRF250X motor instead, electric start would be pretty damn nice. They really should put that motor in a quad...it would be a blast to ride. I'd buy one

[jonboy]

Now thats not a bad idea either. Do they still have the kicker like the crf450x? I would like to have a kicker for back up to start it in case that tiny battery went dead.

[TheNewn]

I'm pretty sure there's some kits you can buy or something. Shouldnt be that hard at all. And you dont have to use the battery from the 450, could use the 300EX's old battery i guess. Mounts already there and waiting. Unless you wanted to put the battery in the airbox or something.

[jonboy]

Its all up in the air right now. I suppose I need to write down a list of functional components that I would like and determine how to make it all work. I've got a friend who has the 300ex and an extra 250x frame that is all in a box in a storage unit that I can get for $150-$200. I'll have to see what all it has and what is missing first and I'll prolly sell the 300ex motor for what I pay for the bike and go from there.

[TheNewn]

Hardest part is going to be finding a used CRF250X motor to stuff in there. Might as well jsut buy the whole bike.

Let me know how it turns out.

[2muchquad]

It would definately be faster than a 300ex but it wont have as much torque.;)

[TheNewn]

A stock 300EX has like 17 HP. how much does a 250F have? like 30 or something?

I'm pretty sure even the 250F will have more torque, or just as much.

[2muchquad]

no it wont actually,it has a short stroke,the powerband is more topend biased,anybody that has riden a 250f knows they are just like 125s,you have to run them wide open to go anywhere.Which engine would be more ideal for plowing snow?Exactly,the 300ex would;)

[Hondamaster5505]

Stock 300ex's are like 17hp and 250f motors are like 33.

On the yamaha db, they make peak power from like 8000rpm all the way to like 13000 or some crap like that

Just go a tooth down in the front sproket.

[300ex_#387]

I think you would have a hard time finding a place for a radiator.

[TheNewn]

I think you might be confusing bottom end power with torque. The CRF250R produces more torque than a 300EX. I looked up a couple dyno's because itgot me wondering. Here is a link to a CRF250X dyno from a 2004 bike.

And the X version creates significantly less power than an R version.
http://photos.motorcycle-usa.com/CRF250XDyno.jpg

Again, thats from a X version 2004 bike.

Here's a 300EX dyno and it has an FMF pipe to boot.
http://www.yamahaoftroy.com/photo_detail.asp?photo=227109

You can see the 300EX with a pipe produces just under 15 foot pounds. The 300EX motor basically hasnt changed since it was introduced. But the 250F's have had several upgrades throughout the years. this early X version created 15.5 foot pounds stock. More than a 300EX with a pipe.

Make it a newer R version of the 250 and it'll be considerably more. They are top end motors, but they still produce more torque.

If it makes you feel any better, the 300EX is better for plowing...if you had a plow on a sport quad...mostly because it has REVERSE...

[2muchquad]

Most people dont ride dynos in the real world.Its possible to get 40hp from a 125 2 stroke,which is almost 3 times as much as a 300ex,bottom line though its still not gonna be any good for plowing,even though its gonna have more torque on the dyno as well.Its not just gearing either.Short stroke motor dont seem to favor the lowend of the rpm scale.

[TheNewn]

My statement was the CRF250R is going to have more Torque. It does. Thats about it. Never went on to say anything about bottom end or plowing snow. As if you're going to plow snow with either quads.

[416exfreak]

I think a 250f hybrid would be the perfect quad for the 13-15 class. You could stomp everyone on 300ex's and probably even 240 blasters.

I say do it.:D

[300ex_#387]

When I ran some 200-300 outlaw races last year I raced again 4 250f hybrids. They are FAST! Most of them ran a 400ex class also and won that too. It was very tough to beat them, but not impossible. I know I did only a few times.

[jonboy]

Well I know that the 250F version makes quite a bit more power than a 300ex. Plus the size of the motor and the fact that it is water cooled makes it a good choice. I dont believe it will be a problem at all to find a place to put a radiator. I can use one from a many number af quads and posibly use an electric fan as well. Folks used to put oil coolers on the 250x and 300ex so it shouldnt be too much of a problem. I do not intend to plow snow with this quad as well. Traction and weight x-fer are large considerations for plowing snow. Like I stated I believed this to be a great hybrid setup for TT or flat track racing.

[bracey]

we are building a 400ex chassis with a 07 crf250r motor will put some pics when it is done

[TheNewn]

It would be great if you could post some pics of the build up/fab while its going on. I'd love to see it. That kind of quad would be the perfect little screamer. I'd want one.

[bracey]

we built a 400ex crf150r early this year i put some pics of it on hear my daughter loves it now we want a little more power

[TheNewn]

That would be great for a young rider. Can you like to the pages? or have any pictures you can post up here?

Edit: I found the thread

http://www.exriders.com/vbb/showthread.php?s=&threadid=257188&perpage=13&highlight=crf150r&pagenumber=2

Here is the thread if anyone else wants to see it

[bracey]

the crf250r 400ex quad will be done this coming week i will post somr pix asap

[bracey]

the crf250r quad is done the pix are in this section under the title 08 racin quads