Modern Vespa

Do you think replacing the little wedge "day time running" light with a PIAA super white bulb (same w5w type) would cause the main head light bulb to go dim? I was fiddling around with my headlight a bit and this last time I put it back together I threw a nicer PIAA w5w bulb in the day time light and now the main bulb doesn't seem to be as bright. I could take it apart and remove the day time light to see if it fixes the problem, but I was just wondering if anyone had any experience with that before I take it back apart.

The ET2 has a very small battery for supplemental use. The bike relies on the charging system to give much of its power. Rev the engine up and see if it gets brighter. The incandescent bulbs do this as well. It is a "feature" of that bike.