Marc Marquez says Honda's new swingarm-mounted winglet, which it introduced in MotoGP Americas Grand Prix practice, is making a difference under braking.
Ducati was the first to race the controversial device in Qatar, which came under protest from Honda, Aprilia, Suzuki and KTM following Andrea Dovizioso's Losail victory.
The device, which Ducati submitted to the FIM as a rear tyre cooling device, was deemed legal ahead of the Argentina race, with Honda submitting its version for homologation at Termas de Rio Hondo.
Honda initially had it rejected as it claimed its use was purely aerodynamic, and thus illegal.
However, resubmitting the design as a rear tyre cooler – which is thought to have been done to highlight a problem with the regulations – it was approved.
Running it for the first time in FP2, Marquez admits there are “positives and negatives” to the device, but highlighted it having a primary effect under braking.
“It's obvious, you saw we try something on the swingarm for the stiffness,” he joked.
“I feel something there that is interesting, but sometimes it is better to come back and analyse, understand and of course we need to take more information about it.
“One of the difference is the brake point. It's downforce, so it's an aerodynamic thing a little bit, but we need to analyse more because there is also some negative points.
“Some positive, some negative, so we need to understand what is better for our riding style.”
Marquez ended Friday's running 0.044s behind Yamaha pacesetter Maverick Vinales in second, and says Honda is struggling set up the electronics for the “special” Circuit of the Americas.
“We had a problem we were trying to fix during all of the day, we were struggling a little bit on that way,” he said.
“But apart from that, [I'm] happy because the rhythm was there. We tried the soft tyre in the rear in the end, it was a good lap.
“We are in QP2, that was the main target, and especially the rhythm is where we are working on more.
“I cannot explain the issue, because we are working on it. But this is a very special race track, it's the only track where we have many first-gear corners.
“So we are trying to adjust the electronics, because during these first races we didn't have many first-gear corners, only one.
“But here you have really long brake points. In the entry and the exit is where we lose more, and where we need to understand what's going on.”
