Coppins will send Queenstown's national MX2 champion Scott Columb, Waitakere's Ethan Martens and Te Puke's Logan Blackburn.
Townley will send Mount Maunganui's national MX1 champion Cody Cooper and fellow Kiwi international John Phillips, of Rotorua.
"Here we have two elite riders who have taken off their helmets and boots and picked up a clipboard and stopwatch. This is a head-to-head battle on the sidelines," says host Bay of Plenty Motorcycle Club spokesman Tony Rees.
"These men know what it takes to win, and it will be great to see the battles between their team riders."
The factory teams will also be competing in Summercross.
Aucklander Hamish Dobbyn, Atiamuri's Hadleigh Knight and Hamilton's Josiah Natzke will represent the CMR Red Bull KTM Team, Taupo's Brad Groombridge, Mount Maunganui's Rhys Carter and Dunedin's Campbell King the Moto City Suzuki Team and Taupo's Nick Saunders, Paraparaumu's Jesse Donnelly, Atiamuri's Dion Picard and Rotorua BikesportNZ.com rider Scotty Canham will be riding for Kawasaki New Zealand .
It will also be worth watching for former national and world champion Darryll King, of Hamilton, local heroes such as Whakatane riders Damon Rees, Blair Gibson, Rhys Robb, Shelby van Beek, Bryce Colbourn, Blake Cheesman, Keanu Viitakang, Sam McPherson and William Milsom, as well as Honda hotshots Peter Broxholme from Tauranga, Rotorua's Michael Phillips, Cambridge's Damien King, Auckland's James Ainsworth and Masterton's Bjarne Frederiksen.
"This event will be the first big hit-out of the season to feature all the major teams," says Rees.
"The club has built a new mini motocross section, with features that will really test the youngest riders, although the more advanced of the 65cc class riders are also invited to race with the juniors on the main track on Saturday."
The Honda Whakatane Summercross is a two-day affair. Minis and juniors race on Saturday and seniors, women and veterans race on Sunday.