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I just bought a good old 2002 crf450r, i had a hole blown in the head pipe when I got it so i immediately put on a t-4 pro circuit head pipe only. My first ride on it it was puking antifreeze, so i thought it was coming out of the weep hole so i put a new water pump seal in it, and still after 5 mins of riding i lose a lot of antifreeze out of the overflow,(water pump seems fine, dont think rad is plugged, and im using prestone), I havent jetted for this pipe but still i dont think jetting would make this big of problem. Oh and im from canada and right now its only about 10 degrees Celsius so something is defiantly wrong if its overflowing within 5 mins.
Thanks

welcome to CRF's Only! if this is happening while you are riding at a reasonable pace (not just idling around) then something is definitely not right. if you are confident the pump is functioning as designed, and you have clean topped off engine/trans oil, no head gasket issues then it's got to be in the radiators, hoses or coolant passages. this is assuming you followed the proper procedure when replacing the coolant to eliminate air trapped in the system.

again, welcome!

ken

Thanks, this is a great set up you got here. Appreciate it. And just to make sure I just finished taking the water pump cover off and flushing the rads. The impeller turns with the motor and seems to be working. I put it all back together filled coolant back up, tipped the bike left got air bubbles out (thats the way ive always done it, not sure if its best) and then started it and idled without the rad cap for a minute or 2. Then took it for a rip and same thing happend I trail ride but fast enough for plenty of air, and after 5min she was pukin again. But the weird thing i noticed this time is the rad/motor isnt even to hot to touch, like i could probably dip my finger in the coolant its that cool. And to note i just finished a fresh oil change and tranny oil change.

could be as simple as a bad radiator cap. get a higher pressure version even if it is good:

http://www.crfsonly.com/catalog/product ... ts_id/3202

ken

I tried my buddies cap today, he has the same bike and did the same thing, but i guess a high pressure one is worth a try.
Thanks

humm...motor not hot, coolant cool and still puking. so, there has to be a blockage somewhere in the system.

Ya like I am stumped, i put the hose to the rad for a good 5 min pumping it in at the top and up through the hose that attaches to the top of the water pump. And it seemed to pump through no prob. Could i possibly have the coolant too full? (try to fill it 10mm below the top) I just didnt want to run the bike to long to see if it stops.

if the coolant overflowing isn't hot i would keep an eye on it but i wouldn't be too concerned if you are able to flush water through the system (indicating their isn't a blockage). after a short ride that would certainly bring the engine to operating temperature and then let it cool off and see what the coolant level is. if coolant is overflowing via steam and boil over that is another issue. normally you can feel the heat through the shrouds when the bike is or is close to overheating. you could also put some temperature strips on each radiator to monitor the temps.

ken

Thank so much for such quick responses really appreciate it, I'll give that a try tomorrow.
Thanks

thank you, crfsonly for your suggestion on putting temperature strips on the radiator. I have the exact same issue on my CRF450X. Could you let us know the temperature at which it should operate and what should be the maximum temperature. I will be able to verify that with a temperature gun.