Hello Gentleman, 
I am having issues getting my radiator cap on my 2000 GG TXT 280 to seal.  I had the rad pressure checked and was informed rad cap was no good.  I have tried three more caps and they won't seal.  I can't see any obvious imperfections.   
The fluid just leaks past the first seal and drips out my over flow hose.  It is a somewhat constant drip and it doesn't matter if the bike is warm or hot.   
Just rebuilt motor and know for sure that it is not a blown headgasket.  Any suggestions would be greatly appreciated.  
Thanks, Bigbore