Te Awamutu's Daniel White (Kawasaki) had led the Junior 125/250cc class battle at Tokoroa, but he was a no-show at Winton and this left the way clear for Dunedin's Grason Veitch (KTM) to nip in and take the crown.
Veitch impressed with his 2-1-1 results at Winton, eventually taking the title by 14 points from Christchurch's Marshall Phillips (Yamaha). Third overall in the Junior 125/250cc class this year was fast-improving Ashburton rider Mitchell Stocker (KTM).
Ashburton's Ben Wall (Husqvarna) came from behind to win the Junior Lites (85cc) class. His 1-3-1 results at Winton meant he won the day by nine points from Palmerston North's Rhys Jillings (KTM) and he eventually secured the title by 12 points from Jillings.
Invercargill's Jack Symon (KTM) had led the Junior Lites class by a solitary point after Tokoroa and he again rode solidly at Winton, but a non-finish in the final race of the championship saw him forced to accept third overall for the series.
2017 New Zealand Supercross Championships:
SX1: 1. Cody Cooper (Mount Maunganui) 117 points; 2. Kayne Lamont (Mangakino) 105; 3. Ben Broad (Ngatea) 86.
SX2 (250cc): 1. Josh Coppins (Motueka) 117 points; 2. Micah McGoldrick (Tauranga) 88; 3. Reece Lister (Kotemaori) 84.