1985-1986 Honda ATC250R Shop Manual, Page 80Get this manual
CYLINDER HEADCYLINDERPISTON
Insert the piston rings into the cylinderUse the piston to place the ring squarely in the cylinderMeasure each piston ring's end gap with feeler gauge
SERVICE LIMIT: 0.5 mm (0.02 in)
INSTALLATION
Clean the piston ring groovesLubricate the piston rings and piston ring grooves with clean 2-stroke oilInstall the piston rings on the piston
the marks facthat the rings _
After installation, check r_otate freely in the ring