The usual cause it corrosion on the plug end and that raises the amp requirement and it get hotter then it should.
Any higher output bulb will draw more amps, it's how much more. The best you can do is replace the end and when you put a new bulb in, use some dielectric grease to prevent the corrosion from starting.
I'm Just Sayin'...
2007 FLHT 103 CID SE-255
IDS drive W/30 tooth Andrews
K&N Air filter system
Vance & Hines Pro Pipe BP & FuelPak.
Torque(A bunch) HP(enough)
I have learned, Just say NO
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I do not work for Vance and Hines, I just like their stuff. Any suggestions I make are to be used at your own risk.