Doin the CRF conversion, have a couple questions for those who have done it.

[Narly R]

I bought an engine, and am probably going to buy a 250r frame, and send it to East Coast ATV, and have them make it fit a 450. If not then I might get a LSR frame, but can I run my 250r radiator with the crf? And has anyone ever did what I am doing? J/W.

[416exmx]

yeah your R stock radidator should work... i used a stock R radiator on a YZF426 quad with no problems, just cant let it set around and idle. i used an oversized radiator on my CRF..

you will also need an Amercian Dream water pump cover, YFZ450 throttle cable, and you have to make a boot between the motor/carb to angle the carb up and to the left...

[team_450_88]

What did u use to make the boot? Mine keeps popping off !! I use a 400ex frame and my frame rail hasnt been made yet so how would I go about doin it I read ur steps but didnt really understand!!

[Narly R]

How do I make a boot? A YFZ Throttle cable will work on my R thumb throttle, and on the CRF carb? What kind of oversize radiator did you use, where did ya get it, and for how much? And why do I need a American Dream water pump cover? Thanks

[JDiablo]

now you can take off that you need a 450 engine....idk do a search narly someone has posted on how to do the crf conversion but iwth a 400ex frame

[SRH]

i dotn have any info on doing a r frame but i know one thing i woudlnt send it to east coast atv=cob job

[416exmx]

Originally posted by team_450_88
What did u use to make the boot? Mine keeps popping off !! I use a 400ex frame and my frame rail hasnt been made yet so how would I go about doin it I read ur steps but didnt really understand!!


i used 2 1/8 ID radiator hose... you have to cut the motor side on an angle to point the carb up. you then have to turn it and cut it at another angle to point the the carb away from the frame rail. i think JB makes a boot like this for around $50. they are pretty easy to make.. mine has never came off

now here may be the downfall, i cant get the quad to run right. it cuts out on bottom- mid range.. we have jetted and jetted and cant get it right. i have come to think that the boot that you have to make from motor to carb has something to do with this. it moves the carb back about 1/4" from where it should be.. i dont know though, my water pump seal went out so now i have to replace it before i can ride it more and figure out the problem

[416exmx]

Originally posted by Narly R
How do I make a boot? A YFZ Throttle cable will work on my R thumb throttle, and on the CRF carb? What kind of oversize radiator did you use, where did ya get it, and for how much? And why do I need a American Dream water pump cover? Thanks

yep YFZ cable works right. you need the water pump relocater to point the spicket foward... otherwise your radiator hose will run right into the exhaust when you do this in a quad frame...

just get on eBay and look for a radiator... a used one goes for around $200... new ones are $300-$500.. Janssen Racing has some good ones on ebay sometimes.. oh yeah if you have a 02 motor, the 03 and up cams will gain a few more HP... they changed them i guess...

[Narly R]

Ohh, ok, thanks a TON for the info. I will save it. I will lookm for a radiator, but if I can find one I will try mine.

Where can I get the water pump cover, and the boot? I dont wanna take any chances on having it run bad. It is a 02 engine. I dunno if I will change anything yet or not.

Why do you say not to have east coast atv do my frame SRH? Many people recomended them, and Arend said he has sent quite a few to them.:confused:

Thanks guys!

[team_450_88]

Originally posted by 416exmx
i used 2 1/8 ID radiator hose... you have to cut the motor side on an angle to point the carb up. you then have to turn it and cut it at another angle to point the the carb away from the frame rail. i think JB makes a boot like this for around $50. they are pretty easy to make.. mine has never came off

now here may be the downfall, i cant get the quad to run right. it cuts out on bottom- mid range.. we have jetted and jetted and cant get it right. i have come to think that the boot that you have to make from motor to carb has something to do with this. it moves the carb back about 1/4" from where it should be.. i dont know though, my water pump seal went out so now i have to replace it before i can ride it more and figure out the problem

I know what ur talking about !! I think I got the hose angled to fit where its not gonna come off but the hose is a lil longer than the ones on the crf bike plus they arent really lined up like they should be and the carb is lined up directyly with the motor so it is taking longer to get gas to the motor maybe thats the problem cause I have jetted and jetted and still the same..I would say tho I like my crf alot better than my friends yamaha yfz's they are bad bikes but I dont think they compare to the crf's!! The crf's just got more mid or bottom end or sumthin and like the handling better also ~~

[team_450_88]

:confused: :confused: whats is JB's Site. I would like to see what there hoses look like or If you would take pictures of yours for me I would really appreciate it !! Thanks

[250rmike]

have u made sure the motor will fit in a r frame yet i was thinking of doing this a year or so ago but everyone told me the motor was too tall. if you measure your motor i can measure my frame for u just to make sure before you jump into this project

[team_450_88]

I havent heard of anyone using a stock 250r frame!! I dont think you can do it. I know all the pros ran 250r based or 250r geometry chassis but they where aftermarket frames that where made for the crf engine!! :blah: ...If I had a 400ex and had everything on it like some of you guys do I would take the crf engine ( around $1500-$2500 give or take ) and fix the swingarm that you have to where it will work with the crf motor and get a radiator and dream water pump cover and you should be set to go!! You will have to do some welding and cutting but it will be alot cheaper than selling you 400ex and fixing up a yfz450 or a 450r!!

[Narly R]

well i cant afford a frame right now, so i am going to just stick with what i have forright now. I need to sell my engine, I will prolly go with a LSR crf/r frame, Arens swingarm, and get a new shock. I have to get a new frame no matter what I do, its broken...:mad: I hav a engine on the way though. I have thought about it more, and i dont think I wanna send my engine to East Coast ATV, because then they might not back what they do, and the frame ISNT made for a 450, and might throw things off. And it will just be too iffy...:confused:


Is there a # or website to where I can get a Carb Boot, AND radiator cover???

Thanks:cool:

[team_450_88]

The Carb boots are pretty easy to make maybe I can get some pictures of some that I have made. ( I have like 2 or 3 of them that has been made laying around the house). Can any of you get pics of ur carb boot? And about the frame, How long do you plan on racing the quad beofore you sell it? If your only gonna race it like 2 year I would go with a 400ex frame because you could buy 5 or 6 stock frames for the price of 1 aftermarket frame..I would just use 416exmx's steps he used when he built his, he explained everything perfect..The frame should last you at least a year if you have it guesseted up and you got everything welded and made right!! I have had no problems out of mine but this winter im gettin another 400ex frame so I can re-make the frame for the crf motor,paint it and guesset it up and have a whole new chassis again for that year but will prolly sell before then cause I wanna race production in the gnc's!!