The raids came after a concealed engine was found in a bike ridden by 19-year-old Belgian Femke Van den Driessche at the recent UCI Cyclo-cross world championships last month.
It was the first proven case of mechanical doping in elite cycling, although Den Driessche denied any wrongdoing, saying at the time the bike did not belong to her.
UCI president Brian Cookson has vowed to crack down on technological fraud, in which a small motor can be fitted inside the frame to provide assistance to a rider.
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Six teams had their bikes checked at Friday's team trial in Banyoles in Spain.
"These bike checks used the same type of equipment which the UCI trialled at the 2016 UCI Cyclo-cross World Championships in Heusden-Zolder where a concealed engine was detected," the UCI said in a statement.
"This equipment enables those performing the tests to investigate large numbers of bikes, both frames and wheels, in a short period of time."
Rumours of mechanical doping have become commonplace in cycling and the UCI said it would continue to arrive unannounced to check bikes in all disciplines throughout the season.
(Reporting by Martyn Herman, editing by Pritha Sarkar)
