WE WANTED AN LED BULB TO FIT INTO OUR FAMOUS 400019 CT110 HEADLIGHT ASSY'S AND THIS SEEMS TO WORK GREAT. I DID TEST THIS ON OUR 1979 CT90 AND IT WORKED, BUT OLDER YEARS DON'T SEEM TO HAVE THE POWER TO FIRE IT UP ): IF I WAS JUST GUESSING I MIGHT SAY THE 1978 AND 1979 CT90'S MAY HAVE MORE VOLTAGE OUT PUT ?? BUT IF YOU HAVE OLDER THAN 1979 I WOULD PASS ON THIS FOR NOW 39LED @ LED BULB IN STOCK 1979 CT90 LOW BEAM (AT_IDLE_!!) @ LED BULB IN STOCK 1979 CT90 HIGH BEAM (AT_IDLE_!!) @ STOCK 1979 CT90 TAIL LIGHT (NO_BRAKE_LIGHT) WITH LED HEADLIGHT BULB (AT_IDLE_!!) @ STOCK 1979 CT90 TAIL LIGHT (NO_BRAKE_LIGHT) WITH STOCK HEADLIGHT BULB (AT_IDLE_!!) @ STOCK 1979 CT90 VOLTAGE ACROSS BATTERY TERMINALS WITH LED HEADLIGHT ON (AT_IDLE_!!) @ STOCK 1979 CT90 VOLTAGE ACROSS BATTERY TERMINALS WITH STANDARD BULB HEADLIGHT ON (AT_IDLE_!!) @ 120CC LIFAN 12V ENGINE IN A 1991 CT70 WITH LED BULB (AT_IDLE_!!) AND USING THE STOCK REGULATOR/RECTIFIER @ REPLACEMENT SOCKET FOR OUR 400019 HEADLIGHT also WORKS WITH OUR 12V LED BULB 1002W (S1170) S1170