right my 98 yz400 was over heating in slow stuff so i added a overflow tank off a wr. the cap isnt an air tight seal and it seemd to empty but never fill still the bike over heated so i tried a 1.6 rad cap off a kx500 ok so as far as i can tell its not bubbled over since, but twice now there has been water leaking from the front of the barrel, from the o-ring on the metal tube that connects to the water hoses. i assume the higher pressure from the rad cap is highlighting other weak links in the cooling chain. ive replaced the o-ring once and am about to do it again. ive been filling the radiator to the top with pure distilled water, i guess the higher pressure cap isnt allowing the excess water to vent. ideally id like some WR / YZ426 radiators which are slightly wider. any ideas how i can cure this so i dont keep blowing orings?