I tried it but it didn't work out very well. The LED lights I have tried are plug and play. The HID was able to plug right into the H4 plug on the bike but it requires an extra 12V power and ground connections for the ballast. The HID lights need an insane amount of power when they are initially turned on (the HID ignition voltage is in the 24kV range). The ballast provides the voltage needed to ignite the HID and to regulate current draw after the HID is tuned ON.
However, I ran into two problems that I was not able to resolve and eventually just switched to LED.
1. When I initially turned on the bike the bike display would be blank. The blue back lighting would be ON but all the text would be missing. After 5-10 seconds I would turn the bike OFF and then back ON and everything would be fine. The HID needs tons of power to ignite but once its warmed up it doesn't need so much.
2. The HID would randomly turn OFF while riding. It seemed to happen when I would go over bumps but I was never really able to definitively determine the root cause.
I tried couple different wiring configurations to try to correct these problems. Initially I had the 12V power and ground connections for the HID ballast wired to an SAE connector and plugged into the accessory plug on the Zero. Next I tried to move the ground wire to connect to the best ground point I could find on the bike (I didn't want to drill into metal or have to scrape away any paint). Under the headlight there is a ground wire that is connected to the dash/headlight mounting spot. It appears this is the 12V circuit ground for the dash and headlight so I though maybe using a common ground would help....nope.
I already had a dedicated 12V battery I installed for some XkGlow LED lights so I decided to connect the ballast 12V and ground to the dedicated battery. Of course, the HID is still plugged into the H4 connector on the bike. Still the same problems. The last thing I tried was to connect the dedicated battery to the ground point I mentioned earlier. This didn't work either.
Ultimately, I ended up switching to the LED headlight even though I liked the color and brightness of the HID much better. I was worried that over the long term I was going to do damage to the display or even other electronics on the bike. However, even if there wasn't any damage caused when the HID ignites, it is completely unacceptable for the HID to randomly turn OFF while riding. During the day I wouldn't even notice until I got home but in the night it's obviously super dangerous to have the headlight just turn OFF without warning. The only way to get it back on would be to turn the bike OFF and then back ON.
I was using an HID meant for a car. I have considered trying to find one that is designed for a motorcycle thinking that they might not draw so much power but for now I am happy enough with the LED that I don't want to mess with it. I might still give it a go sometime if I get bored.