So I bought my bike with HIDs installed by a previous owner. My high beam works without fail but my low beam is a different story. Every time I start the bike, the low beam flashes on for a split second. Usually then it goes right back off. Very occasionally will the low beam fire and stay lit when starting the bike. After riding for about 30 minutes, the low beam will usually come on and stay on until I turn the bike off. But if I shut the bike off and then start it right back up, same thing, low beam lights up while starter cranks but won't stay on. Does anyone have an idea what's wrong? Bad ballast? Bad wiring?
Try swapping the ballast between the high beam and low beam. If the problem switches over to your high beam, then it could be a problem with your ballast. If it doesn't, then continue by swapping your bulbs+wiring harness. If the problem now switches over to your high beam, then could be your bulb/bulb wiring harness. If not, check the wiring upstream to your low beam ballast.
I has a similar situation with my previous bike. Turned out to be a faulty ballast. I replaced it and the problem was solved. Good luck.
I would slave the bulbs before the ballasts just because you ballasts are probably mounted with 3m tape or something. My low light beam is doing it too. Mine works about 75% of the time. I switched the bulbs out for a couple days and it never failed. Mine is probably a bulb. Yours sounds like a ballast though as it flashes momentarily on start up.