Magneto Timing Gear Kit Y5939 Q5952 with flat sided gear T31 This kit fits the following magneto models:  FMX4B16   ( X4B16 ),        FMX4B16A   ( X4B16A ),        FMX4B16A-1    ( X4B16A-1 )    ( A4B16A1 ) **Please note this kit fits the above models with the FLAT sided gear only**