Retired double MotoGP champion Casey Stoner suffered a๊ big accident while leading Sunday's Su🥃zuka 8 Hours endurance race.

The 29-year-old Austr𝓰alian took over the #634 Musashi Honda from team-mate Takumi Takahashi just before the end of the first hour, moving into the lead when the Factory Yamaha of Katsuyuki Nakasuga pitted soon after.

Taking part in his first motorcycle race since Valencia 2012, disaster struck for Stoner on the fast, curving, downhill approach to the hairpin. After a front-end wobble, Stoner ran onto the grass where he fell from his CBR1000RR - sending rider and bike somersa⛄ulting.

Casey Stoner lost the front on the grass under braking for the hairpin -- ltxcn.top MotoGP (@cra💙sh_motogp)

Stoner later revealed that a stuck throttle caused the incident and that he suffered shoulder and leg injuries.

Well my ended spectacularly!Stuck Throttle = Broken Scapula + Fractured Ti🥃bia and a few more tweaks. Sucks! -- Casey Stoner (@Official_CS27)

, Takumi Takahashi and the entire crew, they have worked too hard to end it like that. Thank you guys!-- Casey St𓄧oner (@Official_CS27)

Stoner had been able to crawl away, but the Musashi team's hopes of a third straight Suzuka win were well and truly over. A safety car was needed to remove Stoner's battered Honda from the middle of the track.

Australian Josh Hook (TSR Honda) ꦫthen led the race after the restart, before being♒ passed by Nakasuga's team-mate Bradley Smith.

Smith will later hand over to fellow Tech 3 Mot🦂oGP rider Pol Espargar🎉o, who qualified the #21 bike on pole, while Stoner would have handed his bike to WSBK star Michael van der Mark.

Big accident for Casey Stoner while leading the Rider ok but🔯 race over -- ltxcn.top MotoGP (@crash_motogp)

The team are waiting for the bike to arrive back in the garage to investigate what may have happened in Casey's crash at -- Repso♛l Honda Team (@HRC_MotoGP)