Hardly-Dramamine is a brand of sand bikes, preferred by the Monochrome Boys.
When Roger Wilco went into the Ulence Flats Bar in search of a drink, he was tossed out of the bar by the Monochrome Boys who took offense at the fact that he was in full color. In retaliation, Roger knocked over the Boys' Dramamines and ran for his life. The Boys, angered by Roger's actions, mounted their bikes and went to try and run Roger over. However, Roger was able to successfully dodge the bikes and re-enter the BAR.
In the Disk version of Space Quest 4, the bikes were red, green and blue (as a poke on the RGB color model), while in the CD-version they had been changed to monochrome just like The Boys. Roger comments "How come their bikes can go through the forcefield?". This is not a clue to anything.
Hardly-Dramamine is a spoof of Harley-Davidson.