"I heard it's been raining down there. Perfect. It'll settle the dust."
Ploen was happy to hear a feature of the course was open spaces and rolling paddocks, which he said was the secret to good racing.
"That's what we love. Natural terrain," he said.
Ploen's rise to fame in the early 70s was sudden. Opportunity knocked when a former boss broke his collarbone on the eve of the 1970 Australian Grand National.
Ploen was 19 at the time and took the vacant spot. And won. He went on to win NZ titles in 1973, 1974 and 1975.
"It had rained and rained when I got there. The conditions were just like home," he recalled.
Fast forward 50 years, and he had ridden motocross ever since. He remains spectacularly fit and fast for his age, and was highly competitive.
"I never stopped. I couldn't stop," he said.
Ploen had a front row seat when the sport exploded in New Zealand and bike models went through an era of rapid change from the late 1960s to the early 1980s.
There was an evolution shift as air-cooled, twin-shocked bikes with drum brakes began to give way to water-cooled, single shock bikes with disc brakes, with a shift higher suspension.
More and more imported bikes were on the market as Japanese bike manufacturers began to evolve design.
The NZ VMX was as much a race event as it was a homage to an era and early design of bike. Many riders entered were purists and their, now vintage, bikes immaculate. Racing catered for eras of bike, with classes ranging in stages from pre-1970 to pre-1996.
The event alternated between the North and South Island each year and retained an inter-Island rivalry that existed during the sport's heyday.
The event was held at Seddon in 2019, while the corresponding event last year was cancelled due to Covid-19 lockdown.
This weekend Ploen will be joined by more than 100 riders on a dairy farm owned by Wayne Moxham, himself an avid rider who had no qualms about opening the gates.
Moxham had also been a motocross enthusiast his whole life, and said he was more than happy to have his farm as a venue.
"I've been more than happy to rip up someone else's farm ... hopefully everyone's going to enjoy it," he said.
The acorn hasn't fallen far from the tree with his sons Zac, 24, Tyler, 12, and Ryder, 6, all riding this weekend.
"It's never been forced on them. They want to go out and ride," he said.
It was during the Covid-19 lockdown that Moxham made the course on his farm, to keep the younger boys occupied once they had finished their home schooling.
Moxham said the sport had a strong following in Horowhenua and sponsors were keen to support the event.
The small Koputaroa farming community, near Levin, had always had a special relationship with the sport. For many years the Johnny Old Memorial motocross event was held at a course owned by Mrs Old, not far from the Moxham farm.
There would also be a swap meet area roped off where people could sell or trade in old and new parts.
Meanwhile, a large crowd was expected with good viewing areas to watch the racing. Entry was by gold coin donation.