Just tried out a Baja Designs HID kit. The bulky bulb is a real pain, but oh! it's bright 8-)

The original plan was to mount the HID light on one side of a dual light setup (sv650s), using the halogen side for low beam and both halogen plus HID for high. The nice thing about this setup is being able to put a modulator on the halogen side for daytime conspicuity.

The HID light had to be shimmed back about three millimeters, to give the arc about the same position as the high beam filament on the stock bulb. Left the OEM 45/45 watt halogen in place. Went for a night ride in Tilden Park, a wonderful collection of quiet, twisty, unlighted roads.

Straight and level the HID was very effective; the high beam pattern was clear and brighter than any tungsten halogen light I've seen. Tipped into a turn things got dark in a hurry: the stock highbeam pattern just isn't high enough, no matter how bright the lamp.

Oncoming traffic forced me to dim, and then things got _really_ dark. A single 45 watt headlight is impressively bad. A single 60/55 would be better, but surely isn't good.

Bottom line is that lumens are good, but distribution counts more. If you've got the watts to run cornering lights do it. 60/55 highbeams give decent straight-and-level lighting. A pair of cheap driving lights aimed up and out do more for nighttime twisties than the HID setup.

I just bought a pair of Hella Optilux 1500 driving lights for $50. The problem is that you need 110 watts to spare.

Fitting the HID light to either sv650s or vfr800 looks a bit ugly. The problem is the bulb. In the interests of RFI suppression the ignitor has been mounted tight on the bulb base, with a rigid (and nicely shielded) cable coming off at right angles. This makes for a mechanically inflexible package that fits rather poorly in either headlight assembly. On the sv650s the 3mm shim needed to match the high beam filament position gives enough clearance. On the vfr800 somewhat more shimming is required. An extra shim will spread the beam, which is probably ok given that it's just a driving light and doesn't need tight focus.

A much harder problem is retaining the bulb. The fat, square base on the HID bulb precludes use of the stock bulb retainer. My tests have been done with improvised fastenings.

Sealing the bulb into the luminaire looks like an impossible problem. Both the SV and the VFR have elaborate rubber diaphragms to seal the back of the headlight assembly. It does not fit the HID lamp, leaving the headlight open to dust and water, which will be very hard on the reflectors.

Sad to say, on a cost/benefit basis the HID is a flop. If you want to ride extremely fast in a straight line it might help. For practical purposes cornering lights will do far more good.

A single HID bulb produces much more light than two halogen cornering lights. If a suitable luminaire could be found it would make a good driving light, though a little Cyclops-like in appearance.