1985-1986 Honda ATC250R Shop Manual, Page 224Get this manual
ELECTRICAL SYSTEM
Measure the primary coil resistance between the primary and ground terminalsPRIMARY COIL RESISTANCE: 0.16-0.2 fl
Remove the spark plug cap from the spark plug wireMeasure the secondary coil resistance without the spark plug capSECONDARY COIL RESISTANCE: 3.69-4.51 kfl