He had been promised a "reasonable wage" after years of just breaking even with prize money earned riding internationally and was disappointed when it fell through.
"I've been doing it a long time and I can't be bothered doing it for nothing."
After slogging his way through the national motocross championships to finish second in the 250cc class, he has picked up his game to hold the lead in the country's supercross competition in the same category.
The third round in Tokoroa on Sunday gave him a nine-point buffer over Mason Phillips, of Mount Maunganui, when he placed second in the opening race and won the other two.
"It's been a long season and I haven't been overly motivated.
As the series is going on, I'm getting better," Columb said.
In the fourth and final round set for Manukau on Saturday night, he needs to beat Phillips once and then finish directly behind him twice, to claim his second consecutive supercross lites crown.
From there he will compete in the New Zealand Motocross Grand Prix at Woodville at the end of the month, but after that his future is up in the air.
He hopes to be picked up by an international team or that his British ride finds a replacement sponsor.
Bay of Plenty rider Ben Townley crashed heavily while leading the first of three open class races at Tokoroa, and limped home ninth.
The 25-year-old former world motocross champion and American supercross champion picked himself up and went on win the next two races.
He now has a 26-point advantage over his nearest rival, Justin McDonald, of Christchurch.
Dunedin super motard riders Hayden Scorringe and Scott Baird both had three top-five finishes in the first round of the three-event Super motard South Island Cup.
Debuting his new 450cc KTM SMR, Scorringe said it was "a bit sluggish" as the engine received its run in on the Ruapuna race circuit.
He achieved a 3-3-4 set of results, with Baird right behind him, logging 4-4-5.
They will compete again this weekend, at Teretonga Park.
Defending 125GP champion Tim McArthur, of Dunedin, lost out to Christchurch rider Alastair Hoogenboezem, who won all three races and established a 19-point lead over McArthur.