NOOSA Banks' David Marr normally rides his 1480cc Harley-Davidson around for kicks.
In a moment of either inspired lunacy or clarity - time will tell - the 73-year-old entered the Scootarbor Challenge in which like-minded folk aged 65 or above take off from Port Augusta in South Australia on September 9 to cross the Nullarbor.
And he'll be riding a Piaggio Typhoon 50cc motor scooter.
It may be more with a whining whir than a roar that they will head off down the Eyre Hwy towards Perth almost 2400km away.
Mr Marr, a former RAAF radio technician, read about Scootarbor, an event with an aim of raising $300,000 for beyondblue which helps people battling depression.
"To be quite honest I've always wanted to ride a motorbike around Australia," Mr Marr said.
"So I'll ride a motor scooter instead."
He said he rode bikes when he was younger, but he got into motorcycles big time more than 10 years ago.
He is worried the famous Fremantle Doctor wind could be more like the Roaring 40s out on the plain headed his way.
"That's got me worried - 50ccs punching against that strong headwind," he said.
"We're grey nomads now and I've probably been around (Australia) three times."
Mr Marr said he was geared up for the ride that should have the 50cc "speed demons" sweep into Perth on Sunday, September 21.
"Fortunately I'm fairly fit," he said. "I've got a bit of experience. I hired a motor scooter in Vietnam a couple of years ago."
He said it was "just about the size of a mower".
He has raised more than $1200, - way past his initial goal of $700.