Championship leader Alfie Davidson hit the ground at Oulton Park as he topped the timesheets in FP1.
The Aprilia IN Competition Racing rider clocked a time of 1min 42.060secs to go 0.414s clear of Cameron Dawson.
Asher Durham was third fastest at the flag, with Harley McCabe fourth and Peter Willis fifth.
Pirelli British Sportbike Championship, FP1 result:
1. Alfie Davidson (Aprilia IN Competition Racing) 1min 42.060s
2. Cameron Dawson (Powerslide Suzuki Racing) +0.414s
3. Asher Durham (Powerslide Suzuki Racing) +0.553s
4. Harley McCabe (Fibre Tec Aprilia by MLav Racing) +0.573s
5. Peter Willis (Moto 12/CFMOTO) +1.137s