Honda identifies Stoner crash cause

Stoner sustained a broken shoulder blade and fractured tibia in the accident at the Formula 1 venue's hairpin.

He was making his first competitive start since retiring from MotoGP at the end of 2012.

The Australian immediately cited a stuck throttle as the cause of the violent crash, and Honda has now narrowed the problem down to the throttle cable.

"Checking the throttle, which is a particular specification for Endurance HRC Factory bikes, and different from the standard throttle used on the Honda CBR1000RR road version, a malfunction was discovered related to the throttle cable," said a Honda statement.

"This kind of problem hasn't arisen before, however, HRC will cease using this throttle specification and will design a new one to be used for Endurance races.

"HRC would like to apologise to Casey Stoner and thank him for the effort he made in attending the Suzuka 8 Hour event."

Stoner had been sharing his Honda with World Superbike rider Michael van der Mark and test rider Takumi Takahashi.

Yamaha won the Suzuka event with Tech 3 MotoGP duo Bradley Smith and Pol Espargaro and its sometime works MotoGP stand-in rider Katsuyuki Nakasuga.