I always need to trim a little from the base of the H4 bulb before I install it in the BA20D socket. If you headlight was aimed properly before, and now it isn't, the tight fit of your H4 bulb is causing an improper alignment of the bulb with the reflector.
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Spud
"Never argue with an idiot. He will drag you down to his level, and beat you with experience."
Mark Twain
2015 Zongshen ZS250GY-3 (RX3)
2006 Zongshen ZS200GY-2 (Sierra 200)
2005 Honda XR650L
2004 Honda CRF250X
1998 Kawasaki KDX220
Mods made to my Zongshen ZS200GY-2:
http://www.chinariders.net/showthread.php?t=6894