[Water Warrior 2]

There are adjustment screws for the headlight. At about 4 o clock and 8 o clock on the head light bucket near the front. L side(clutch side) is the height adjuster IIRC. REquired tools, a screw driver, flashlight and a wall. Go for a ride. Repeat if necessary. Also try a SilverStar bulb from Sylvania, they are brighter but do not draw any more wattage. They do have a slightly shorter life span due to vibration on the GZ but worth the $ if you ride a lot of nights. I have had SS bulbs in my Vstrom for 4 years now with no failures but the bike is also a lot smoother and the lights are not directly mounted to the front end but in a fairing. SS in my Ranger too. Best bulb for the $ in my opinion.

You may also want to install one MR-16 35 watt halogen light similar to the pic. The GZ will not support much more power draw.
The pic is a MR-11 so it is a bit smaller in overall size.