Leon Haslam admitted he had a "weekend to forget" in the fifth round of the World Superbike Championship at Salt Lake City in the United States.
The Derbyshire rider managed only eighth and 13th in Monday's two races.
The BMW rider told his website: "This was a weekend to forget without a doubt. We have again identified some issues with the machine we must solve."
Haslam, who lies fifth overall after five rounds, is next in competition in San Marino from 10-12 June.