"A couple of things like that held us back," he said.
"I didn't even think it would be an issue.
"It was a difficult weekend, we weren't into it."
A new development class for 2017-18, Gixxer racing is done on GSX-150F machines, with competition rules stating they must all be maintained to an identical standard.
Greymouth's Clark Fountain won the final race, which moved him up to third in the final season points, while Ross was second and also took season runnerup, and Newton's third place was more than enough to comfortably guarantee him the title with Walker out of contention.
While disappointed with the conclusion, Walker has enjoyed the new division, which started during the Suzuki Series and carried onto the national championships.
"I filled up the top of the wardrobe [with trophies].
"It's been awesome fun, heaps of learning.
"I'll bring it back next year and take the lessons learned."
The teenager is working on the testing and developing of a new bike to enter the Pro Twin division, with the winter season also beginning in just over a month.
"That will be 110 per cent moving forward. That's the most exciting," he said.
Meanwhile, Whanganui's superbike racer Jayden Carrick also had a difficult weekend in Taupo, as during practice riding on Friday it was revealed he had an engine issue with his Kawasaki ZX10.
Supporter Mark Paul said with no time to repair, Carrick was loaned a complete race bike by one of his sponsors.
"Although the suspension etc was not set-up for Jayden, it was a clear display of his skill in that he brought the bike home in eighth place [in Race 1]."
For Race 2 on Sunday, Carrick was forced to pull out due to a loose brake, and then during the third race he had again worked his way up to eighth place when he was forced to withdraw with a loose foot peg.
"One can only imagine how well Jayden could have gone, had he an ounce of good fortune go his way," said Paul.
"The performances Jayden displays when his bike is going well, is there for all to see, and the two DNF's on Sunday were both factors on the borrowed bike, and are no reflection on Jayden's hard working team of volunteers and sponsors."
Wellington's Sloan Frost was able to wrap up the Superbike title in Taupo, with Whakatane's Mitch Rees finishing second overall and Glen Eden's Daniel Mettam third.