Monster Energy Kawasaki has officially confirmed its 2027 factory 450 lineup, announcing the signing of Malcolm Stewart alongside returning rider Garrett Marchbanks.
The announcement, made October 28, comes just five days after Kawasaki and Chase Sexton mutually agreed to part ways, ending their partnership after a single season.
Stewart, who previously competed for Rockstar Energy Husqvarna Factory Racing, will make the move to Kawasaki for the upcoming SuperMotocross season.
Marchbanks, meanwhile, has earned a contract extension following his successful 450-class rookie campaign.
Together, the two riders will represent Monster Energy Kawasaki aboard the new 2027 KX450F-SR.
Malcolm Stewart Returns to His Kawasaki Roots
For Stewart, the move carries significance beyond a change of motorcycle manufacturer.
The 34-year-old American began his racing career aboard Kawasaki machinery as an amateur, competing through the manufacturer's Team Green development program.
Now, more than a decade into his professional career, Stewart is returning to the same brand as a factory 450 rider.
Kawasaki's October 28 announcement confirms he will carry his familiar #27 as he begins the next chapter of his career.
Stewart described the opportunity as a return to his roots and expressed enthusiasm about joining the team and beginning work with its new motorcycle.
The move also reconnects the Stewart family name with Kawasaki, the manufacturer closely associated with the early professional career of Malcolm's older brother, James Stewart.
For Malcolm, however, the opportunity is about building on his own achievements.
A Proven 450SX Race Winner
Stewart arrives with extensive experience in professional Supercross.
He captured the 2016 AMA 250SX East Championship before establishing himself as a regular competitor in the premier 450 class.
His long-awaited first 450SX Main Event victory came at Tampa in February 2025, a career milestone after years of chasing the top step of the podium.
Later that year, he also won the King of Paris Supercross title.
During the 2026 SuperMotocross campaign, Stewart recorded one podium and 14 top-10 finishes across the championship disciplines, according to Kawasaki's announcement.
His addition provides the team with an experienced rider who has demonstrated the ability to compete against established 450-class contenders.
Stewart's next challenge will be adapting to the factory Kawasaki program and its updated 2027 KX450F-SR.
Garrett Marchbanks Earns Another Year With Kawasaki
While Stewart is the new arrival, Garrett Marchbanks provides continuity for Monster Energy Kawasaki.
The former Kawasaki Team Green and Monster Energy Pro Circuit Kawasaki rider completed his first full premier-class season in 2026.
Marchbanks earned 450SX Rookie of the Year honors, highlighting a debut campaign that showed steady development throughout the championship.
His progress continued during the outdoor season, where he recorded career-best fourth-overall finishes at Thunder Valley and Unadilla.
He also achieved five top-five SuperMotocross finishes and concluded the 2026 SMX World Championship in sixth place.
Those performances helped secure his return to the factory Kawasaki program for 2027.
Marchbanks enters his second 450 season with established familiarity with the team, while Stewart brings additional race-winning experience to the lineup.
Kawasaki Rebuilds Following Chase Sexton's Departure
The announcement also resolves a major question created by Chase Sexton's unexpected departure.
On October 23, Kawasaki confirmed that it and Sexton had mutually agreed to end their relationship immediately.
The separation came after just one season together, despite the original multiyear agreement.
Sexton delivered two 450SX Main Event victories aboard the factory Kawasaki in 2026, but the partnership ultimately concluded before the 2027 season.
With Stewart now signed and Marchbanks confirmed for another year, Kawasaki has officially established its two-rider factory 450 roster.
The combination creates a different team structure heading into the championship.
Stewart provides extensive premier-class experience, while Marchbanks enters his second year looking to build on a promising rookie season.
Sexton's next team has not been officially confirmed in the announcement covered here.
The New 2027 Kawasaki KX450F-SR
Both riders will compete aboard Kawasaki's new 2027 KX450F-SR factory race motorcycle.
The updated platform will play an important role in the team's preparation for the upcoming season.
Stewart will be transitioning from Husqvarna equipment, while Marchbanks will be adapting to the updated Kawasaki platform after competing on the previous factory motorcycle.
For the team, the preseason will involve integrating its new rider, preparing the updated bike and building on the development progress established during 2026.
The two-rider lineup gives Kawasaki a combination of experience and continuity as it enters a new competitive chapter.
What to Expect in 2027
The 2027 Monster Energy AMA Supercross Championship is scheduled to begin January 9 at Angel Stadium in Anaheim, California.
Stewart enters the season with an opportunity to pursue additional 450SX victories with a new factory program.
Marchbanks will look to take another step forward after earning Rookie of the Year honors in 2026.
For Kawasaki, the announcement brings clarity to a factory roster that had been uncertain following Sexton's departure.
The team now has two confirmed riders and an updated race motorcycle as it prepares for Anaheim 1.
Monster Energy Kawasaki's 2027 factory 450 lineup is official: Malcolm Stewart and Garrett Marchbanks.
Supercross.com will continue following Kawasaki's preseason preparations, rider developments and official team announcements ahead of the 2027 championship.
Explore Malcolm Stewart's and Garrett Marchbanks' rider profiles, revisit our coverage of Chase Sexton's Kawasaki departure, and follow the complete 2027 Supercross Team Lineups on Supercross.com.
Photo: Monster Energy Kawasaki — Malcolm Stewart aboard the new 2027 Kawasaki KX450F-SR from the team's official announcement.
