Dixon said it had been 10 years since the team was involved in the women's world championship.
"A friend mentioned to me that Courtney was looking for a competitive ride in this year's GPs. It took some thinking about, but Kawasaki were keen, especially since their previous champion Livia Lancelot has retired. I expect Courtney to bring Kawasaki the world title."
Duncan has been back on the bike for the past six weeks after an extensive rehabilitation programme to heal a foot ligament injury. It caused her to miss the final two rounds of the 2018 WMX, where she held a dominant 21-point advantage. Duncan had won five of the eight WMX races she contested in Europe last year.
She has had a string of bad fortune over her three WMX campaigns.
In 2017, she was winning the second-to-last race of the season when she swerved to avoid a cluster of five fallen riders blocking the track and crashed into a fence — recovering to finish sixth. The race jury initially ruled the results would be awarded on the placings from the lap before the track was blocked, when Duncan was in front. But this decision was then changed and the results at the end of the race were reinstated, meaning she did not have enough points to win the championship.
She won the season's last race by 46 seconds, finishing third in the WMX, three points off top spot.
In 2016, while leading her debut championship — after winning three of her first four races — she crashed into an errant photographer who was standing in the wrong place on a jump. She injured herself badly and missed two rounds and consequently the title.
Duncan flew out recently for her new base in England, where she is preparing to ride her Kawasaki KZ250F in the five-round WMX series.
Women's Motocross World Championship
Round 1: March 31, Valkenswaard, Netherlands
Round 2: May 19, Agueda, Portugal
Round 3: July 28, Loket,
Czech Republic
Round 4: August 18, Imola, Italy
Round 5: September 8, Afyonkarahisar, Turkey