Broken or whipped out rotor timing gear?  Nooooo problem! We got you covered with our brand new fiber timing gear for all "J" series Fairbanks Magneto's!  All "J" series Magneto's have the timing gear located in the lower cover. Always check to make sure your purchase the correct timing gear. The Fairbanks "X" or known as the FMX, has the timing gear mounted on the breaker plate. Two completely different timing gears.  This gear replaces F/M P/N- Y5939.  See our P/N 1507-31 for the correct timing gear for the "X" series Mags.