Motorcycles

"Motorcycle boots" are mentioned in the Freak Out! Hot Spots, item #16.

A line of Bwana Dik lyrics goes: "My dick is a Harley, you kick it to start".

The "motorcycle man" is Frank Zappa's role in Titties & Beer.

In The Adventures Of Greggery Peccary the lyrics go "... They zoom after him in all manner of cars, trucks, garishly-painted buses, and motorcycles. ..."