Veteran Walker scored an emotional maiden victory at Oulton Park last season.
The 40-year-old fans’ favourite was in contention for a position in the Showdown until a crash at Knockhill left him with broken heels but he fought back to claim top 10 finishes on his return from injury later in the season.
Walker said: “I love racing in BSB and I am absolutely chuffed to be back on the grid in 2013 with Kawasaki. The numbers tell the story; Kawasaki won the BSB and both Superstock titles which is a massive achievement and I feel that we can only continue to move forward.
"Last year was the team’s first season in BSB and we won a race, which was an amazing feat. I think if it hadn’t been for the crash at Knockhill we would have been in with a shot of the Showdown so that bodes well for 2013."
He is joined by 19-year-old Buchan who impressed in his Championship debut in round six of 2012 with MSS Bathams Kawasaki.
The Essex rider recorded a strong fourth place finish at only his second event and the former title contender in the National Superstock 1000 Championship is now relishing the challenge of his first full campaign in the Superbike class.
Buchan said: “I am so happy to be back riding a Kawasaki, especially to be in BSB full time as that has always been one of my goals. It will be my first full season in the championship but I think working with the Bournemouth Kawasaki team and Chris will help me make progress all the time.
"I wasn’t very lucky last season but I think we can turn things around next year and we know that the Kawasaki is capable of winning races so we need to get ready and come out with a big boom at Brands Hatch.”
- Sports & Recreation