trx450r loosing coolant??

[trx416m]

My brother has a '05 trx450r that i recently put a 480cc cylinder works kit in. It has also has a new, used head with a mild port and polish that we bought off ebay and an hrc cam. We race hare scrambles and after the last 2 races it has been really low on coolant. The fan works, but the weep hole on the side of the head always has a significant amount of fluid coming out of it after the races compared to my other quads. I dont know if its coolant or oil. We have tried a new head gasket with no luck. Im thinking the head we got may be cracked but not sure. The oil is not milky either though. Any suggestions would be appreciated.

[DnB_racing]

more then likely the fluid from the weep hole is oil from the seal around the plug chase bieng worn or cracked, or a loose spark plug cap allowing water to get in

you can check your coolant issue by .... before starting quad remove cap and let warm up, the fluid shouldn't be bubbling it might overflow when warmed up but not shooting out, and you should be able to make sure that it is circulating this way also, if shooting out then your pressurizing the cooling system from a leak or crack,
and also when the day is the coldest you might be able to see steam out of exhaust

or it could be just a bad overfull line with a hole in it, when hot it could be just leaking out instead of going to the bottle

also make sure your not overfilling the overfill bottle or it will cause over pressurizing your system and you could overheat and overflow and will also cause your radiator to run low

[trx416m]

thanks, We found the problem though, the top of the radiator has a small leak that was not noticeable until we got the machine really warm.