1985-1986 Honda ATC250R Shop Manual, Page 23Get this manual
MAINTENANCE
RADIATOR COOLANT
Place the ATC on level groundCheck the coolant level of the reserve tank with the engine running at normal operating temperatureThe level should be between the "F" and "L" level linesIf necessaryfill the tank to the "F" level line with 5050 mixture of distilled water and anti-freeze
"F" LEVEL LINE
"L" LEVEL LINE