MOTORCYCLE FAILED WHEN FUEL GAUGE READ 1/8TH TANK FULL. RIDER LOST POWER ON FREEWAY AND WAS STRUCK FROM BEHIND WHILE TRYING TO REACH SHOULDER FOR SAFETY. HD SAYS THAT AT APPROXIMATELY 1/8TH TANK READING, MOTORCYCLE NEEDS TO BE SWITCHED TO RESERVE TO AVOID RUNNING OUT OF GAS, BUT MANUAL CONTAINS NO SUCH REFERENCE. BELIEVE FUEL GAUGE IS INACCURATE AND/OR IS INCONSISTENT WITH RESERVE SYSTEM. COULD BE OTHER PROBLEMS, SUCH AS FUEL VALVE.*AK