A legal option is to just swap out the bulbs with some that provides yellow light.

Color temperature are measured in Kelvin and a very yellow one is 2500K while a major brand like Osram All Season H7 or Osram All Season Selective Yellow is 3000K

I've tried the NOK7656 - NOKYA HYPER YELLOW H7 55W 2500K Light Bulb For Motorcycle but it did not last long, even trough it was the vibration resistent version.

Now i'm riding with Michiba Gold Vision 3000K from EX_Technik on ebay. They have lasted 10000km so far with the low beam on all the time

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2011 Yamaha XT660Z ABS T�n�r�.

• Puig +8cm dark screen, Garmin Zumo 220, Scottoiler eSystem v2
• Barkbusters Storm with external weights, Noname 30mm bar risers & EzMoto alu. levers
• Kev's O2 Controller, Mccoi stepless controller with Hein Gericke heated grips
• TT +4cm seat, Pivot Pegs, Altech stainless sprocket cover