'It’s believed by multiple sources within the paddock that Yamaha is currently under investigation for allegedly using illegal valves in their M1 engines at the opening round of the year in Jerez, where the manufacurer suffered a number of mechanical issues and subsequently was forced to take corrective action'.
the-race.com
Yamaha engine investigation puts title hopes at risk - The Race
Yamaha is believed to be under investigation over an engine discrepancy, which could impact all three of its MotoGP title hopefuls.
the-race.com