Yamaha revealed its proposed 2018 in-season fairing update during Monday's official test at Brno.

The design is a more radical evolution of the current fairing, including a unique cutaway front mudguard.

However Valentino Rossi - the only rider to use the new fairing, with Maverick Vinales resting following his big lap one accident in the race - said:

"Yes, I tried the cowling also to help with the wheelie, but it feels very similar."

Since it has not been used in a grand prix weekend, it is not yet clear if the fairing has been deemed legal by technical director Danny Aldridge. Yamaha could also choose to revise and re-test the design if they wish.

However once a rider has taken a new (homologated) fairing design on track during a GP session, it counts as their one in-season update and cannot be withdrawn.

Honda and Ducati have already used their in-season fairing update. The Suzuki, Aprilia and KTM riders - like Yamaha - are thought to have their 2018 update still available.