Green’s Dictionary of Slang

mono n.

In phrases

pop a mono (v.)

(Aus.)

1993		Aus. Word Map 🌐 mono As in ‘pop a mono’ - to lift the front wheel of your old dragster, so you're riding on one wheel, hence ‘mono’: You should’ve seen the mono I just popped!
2008		J. Roy Town 213: Clinton Werrington goes by on his motorbike, & he sees us & tries to pop a mono.