1987-2003 Yamaha YFZ350 Banshee supplementary service manual, Page 152Get this manual
RADIATOR
1COOLANT RE-
REMOVAL 1Drain: Coolant Refer "CHAPTER PLACEMENT" section
Do not remove the radiator cap when the engine and radiator are hotScalding hot fluid and steam may be blown out under pressure, which could cause serious injuryWhen the engine has cooled, open the radiator cap by the following procedure: Remove the radiator cover by removing the screwPlace thick rag, like towel, over the radiator cap, slowly rotate the cap counterclockwise the detentThis procedure allows any residual pressure escapeWhen the hissing sound has stopped, press down on the cap while turning counterclockwise and remove it