Radiator for conversion question

[Chanman420q]

Does the stock 250R radiator keep the engine cool enough when running it on a hybrid, for like a yz426? I dont see how a radiator made for 250ccs is big enough to keep a 426 cool.

[worm]

youre right and i htink that w/ it a high performace 4 stroke that makes it evenowrse..thats why everyone runs larger bigbore 250r radiators.. not a stock one.. when i wass interested in doing a conversion i loooked into jansenn racings radiaotr

[Chanman420q]

Originally posted by worm
youre right and i htink that w/ it a high performace 4 stroke that makes it evenowrse..thats why everyone runs larger bigbore 250r radiators.. not a stock one.. when i wass interested in doing a conversion i loooked into jansenn racings radiaotr

ive been reading around and a lot have said things about using a stock 250r radiator and it doesnt sound big enough to keep it running good

[MOUSE]

some people run a stcok rad but i would suggest a oversized and a radiator cap with a little bit higher pressure rating. than the stock cap. :macho

ive talked to several people and thats what im going with im doing the 426 conversion, a friend is using his stock 250r rad on a yz400 and he boils over if he idles for more than a few minutes

[mxracer111]

raising the pressure of the cap is NOT a good idea!... you will blow head gaskets and such by putting more pressure in the engine. use a STOCK PRESSURE CAP, if your boiling over you have something else wrong, such as jetting maybe causing it to run hot...

i have a Walsh radiator in my yz conversion, using a stock cap. it is about 2 times as large as a stock 250r radiator.... works fine. i also have a lot of mods to the motor and it seems to stay cool

[400exBro]

i have seen some with stock 250r rads and they haven't had a single problem...

i would take a safe way and uses the over sized rad... JRD rad is a good one, Forum uses one on his yzf426 and said he liked it and is happy with it...