CRF hybrid questions

[joeb2300]

I have a 400ex frame that I converted with the help of atv four play.

What exhaust systems work best with 400ex geometry? I think 450r exhausts work but not sure.

Switching the throttle from twist to thumb throttle, is it as simple as hooking the throttle cable to the 400ex thumb throttle or do i need something else?

I've heard the 250r radiators work best, are there any other aftermarket brands other than PWR?

And where the hell can I find a Kick Start extension?

Also I plan on making the intake like Rootars crf he had a while back. I would like to know what intake boot he used for the air box and what size pipe he used for the intake if anyone could help that would be great!

[joeb2300]

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[JOHNDOE83]

I would use the CRF pipe and make it work or use the CRF header and adapt a 400ex pipe to it.

Radiators are made with overkill also, I know a guy who runs a 450r without a rad, he just runs the line from one to the other, I used a smaller rad for my build, its a third the size of the CR rad but the temp never got over 160 degrees. Try to look up cr80 and cr125 rads.

The kicker, aparently people make them but Ive yet to find one thats made for a CR250, I made my own.

The pic you posted looks like WAY to much work to attach a airfilter or air box, that just looks like overkill to me, open filters are fine if your not going mudding or driving through ponds and streams.

If you REALLY need a airbox, Im sure there is a much easier way.

post pics of your build so we can help :D

[mx Eli]

Not sure if your serious about the radiator thing or not... but you for sure needs a radiator. A 250r or 450r one are about the same. A 450 one would be cheaper prolly.

That way he made his intake it made the straitest path for the intake,getting nice path for the air is one of the hradest part to figure out on hybrids, his is one of the best I've seen for the crf/ex conv ersion

For the pipe, most use a 450r pipe, i have heard 04/05 ones work best but all require a small amount of fixing to work perfect

Rooster is still on here so he should be able to help you some

[mirror_racing]

do you think a 06 plus TRX 450 header would work on a 05 CRF motor?

[JOHNDOE83]

Originally posted by mx Eli
Not sure if your serious about the radiator thing or not... but you for sure needs a radiator.

Im not saying to "not" use a radiator, I used a 1985 cr125 radiator in mine. I was just saying some are made with overkill and are alot bigger then they need to be.

About the air box thing, Im just sayin there has to be a better way then making all that stuff into the frame.

[mx Eli]

Originally posted by mirror_racing
do you think a 06 plus TRX 450 header would work on a 05 CRF motor?

the only thing would u have to use TRX exhuast studs as they are alittle longer. other then that it would bolt up perfect, might have to do alittle fabing to get the head pipe to connect to the muffler right.

with the intake, there might be easier ways but they arnt the best for flow and you do it if your not going to do it right, u dont have to go to the extreme of ross but you can use his ideas and tweak them if needed

[mx Eli]

also theres a couple people who make kick start extentions on here, potherwise i think eastcoastatv might have a couple (i think thats the name anyway) but they come with a hefty price

the crf has a push and pull cable to operate the throttle, you want to hook the pull cable to your ex thumb throttle and itll work

[hybrid400]

I used a crf header with a trx450 pipe... Very small modification to the pipe. I also used a fluidine radiator for a trx450... I used a throttle cable from an 05 trx450 and I believe I sent it through the bottom hole on the crf carb.. I may be wrong about which hole, but I will check after work and let you know..

[mirror_racing]

Thanks man. I'm trying to get this thing finished before this season but I still have a way to go and still need some more parts.

[hybrid400]

The trx throttle cable goes into the bottom hole and loops around... Are there anymore pics on here of the intake setup above?

[mx Eli]

Originally posted by hybrid400
The trx throttle cable goes into the bottom hole and loops around... Are there anymore pics on here of the intake setup above?

do a search its in the very last pagest of the hybrid section

[joeb2300]

I don't think it is overkill to make the intake like ross' bike. I mean why do something half assed when it is a simple modification that makes everything easy.
And

I'm not going to put a cr125 radiator in it. Im not just trying to throw an engine in my ex frame that "will do" I want things to look professional and functional.

Thanks for the info guys! much appreciated!

[joeb2300]

anyone know what boot that is up there^

[flyjum]

Rossier exhaust works on my
its a JB racing mount kit
You need to make a mount on the rear subframe but it clears

its pretty close to the rear shock as well