1985-1986 Honda ATC250R Shop Manual, Page 24Get this manual
MAINTENANCE
RADIATOR CORE
Remove the radiator screenCheck the air passages for clogging or damageStraighten bent fins or collapsed core tubesRemove insects, mud or any obstructions with compressed air or low water pressureReplace the radiator if the air flow is restricted over more than 20 of the radiating surface
COOLING SYSTEM
Remove the radiator shroudsInspect the hoses for cracks and deteriorationReplace, if necessaryCheck the tightness of the hose clamps and radiator mounting bolts