Australian former MotoGP rider Anthony West, who competes in the World Supersport Championship (WSSP), has been provisionally suspended for a doping violation.
On Friday, the governing International Motorcycling Federation (FIM), stated that the 37-year-old tested positive at a WSSP race at Misano, Italy, on 8 July.
The statement did not detail the substance detected in the sample.
The Kawasaki rider has been barred from participating in any motorcycling competition or activity until further notice, and can still request the analysis of a B sample.
This is the second time West fails a dope test in his motorcycle racing career.
Second slip for Anthony West
The rider tested positive for the prohibited substance methylhexanamine while competing in Moto2 at the 2012 French Grand Prix.
As a result, the FIM suspended him for 18 months.
At the MotoGP, West made 32 starts racing with a non-works Honda team in 2001 and then the Kawasaki factory team in 2007-08.
His most recent top-flight appearance dates back to 2015, when he stood for Karel Abraham aboard an Open-class Honda bike.
West is currently sixth overall in the WSSP standings, with 51 points from seven races. Germany’s Yamaha rider Sandro Cortese leads the standings with 138 points.