It started in May when Casey Stoner told MotoGP: “I’m just not that into you”.

This weekend, the long goodbye for the Australian his peers rate as the fastest and best on two wheels enters its most bittersweet phase.

It will be Stoner’s last Australian Grand Prix as he attempts to win six in a row at Victoria’s Phillip Island before he retires at the end of the season, aged just 27.

Record crowds are expected for the final home soil appearance of Stoner’s glittering career.

Many will be asking the same question virtually all who have ridden world motorcycling’s premier class are.

Just as he was expected to ride into history, why is Stoner instead riding into the sunset?

If his sport was simply about racing bikes at high speed, two-time MotoGP world champion Stoner would not be quitting at the peak of his powers.

But it is the circuit life and its off-track demands, and where he sees the sport heading, that have sapped love from marrow.

Stoner, who has battled illness and injury throughout his career, knows also the extraordinary stress MotoGP riding puts on bodies.

Bodies which absorb phenomenal shudder and force for 20 races and countless laps a year, not to mention the regular high-speed crashes – even for great riders like Stoner.

So many past champions walk with a limp or shake hands with bent, wizened fingers.

From a bike, there is nothing to catch you when you fall.

Stoner has chased the dream since he was 14 – moving with his family to England to work his way through the road racing classes.

These days, he has his own family – wife Adriana and baby daughter Alli – and a wish to spend quality time with them.

Stoner goes into Phillip Island just weeks after ankle surgery to repair a serious injury following a fall.

It wrote off his chances of a third world crown to add to his 2007 and 2011 titles.

But he has recovered well enough – though he admits he is still in pain – to farewell Phillip Island.

“It’s been built up to be a very big weekend,” Stoner said.

“People have been expecting for me to win for more than just this year. It’s not something new to me.

“Last year I didn’t feel the pressure that I had in previous years.

“I’m not really feeling pressure here. I know what my capabilities are, and unfortunately they’re not the same at this point.

“The only thing I can do is my best.”

Whatever the result on Sunday, Stoner will leave the sport recognised as one of its greats.

He is fourth on the all-time world 500cc/MotoGP winners’ list.

Only Italian superstars Valentino Rossi and Giacomo Agostini and Australian Mick Doohan have won more races than his 37.

At the track he has dominated since 2007, Stoner’s achievements in world motorcycling will forever be recognised.

Turn three, a bend Stoner admits was his Achilles heel early in his career, has been named Stoner Corner.

He joins the most exalted of Australian motorcycling company with that honour. Wayne Gardner and Doohan both have sections of the track named after them.

A trophy presented this week to mark the occasion bore a plaque saying Stoner has won the Australian Grand Prix five times.

Such is the hope for a fairytale that he was given an additional plaque which says six, and extra screws just in case.

A move from two wheels to four looms as his next career move.

Driving a V8 Supercar, which comes with the added bonus of a more relaxed life in Australia, looks a certainty, though the smart money is on an extended rest before he leaps fulltime into a car.

Stoner has tested a V8 Supercar for competition benchmark Team Vodafone and impressed.

Others have done what he is contemplating.

The late Gregg Hansford and Gardner both made the transition from the world motorcycle championship to driving touring cars.

It will come as no surprise if he excels.

Stoner has always been swift.

Sadly, so too was his top-flight motorcycling career.