Marc Marquez confessed he and Honda 'we must improve a lot' after finishing the opening day of 2016 MotoGP testing in seventh position, 1.594s behind Yamaha's Jorge Lorenzo at Sepang.

Of greatest concern was that a new Honda engine offered only a 'very small improvement' over the previous 2016 spec and the long-running puzzle of aggressive engine character remains unsolved.

"Maybe Jorge is too far! Compared to what we expected," he smiled, when asked about the gap to the top. "About the rest, Valentino - the second guy - is closer. We expect already a little bit [this situation] because it takes time to work with the electronics and find a good feeling with the tyres.

"With the tyres I didn't have a big problem, but looks like with the electronics and with the character of the engine still, I didn't feel comfortable. So for that reason today was a little bit of a special day. We tried to work and of course we tried to push, but it looks like we must improve a lot."

Marquez described the newest engine as having some "small modifications" and offering "a very small improvement on the connection of the gas [throttle]. The first touch. We must keep working to find better acceleration, which is where I think we lose more."

After confirming that both 2016 engines are still very aggressive, Marquez explained that adapting the new single ECU software to the RC213V continues to complicate their efforts.

"The electronics are not fixed 100%.... If you [cut] power, you lose time. If you put more power it is aggressive, a lot of movement. We are trying to find the best compromise."

That description underlines how integral electronics are to making the RCV engine rideable. It also contrasts with the words of Suzuki's Aleix Espargaro, who like Marquez has a lot of ECU work to do, but went one-second faster without using any traction control. "The engine was so smooth, so natural and much better than with the electronics," said Espargaro, who was ninth and 1.85s behind Lorenzo.

In terms of the new tyres, Marquez admitted that his all-action braking style is not best suited to the more sensitive Michelin front.

"Always for my riding style maybe this is not one of my best circuits, but with the Bridgestone I was able to brake really late and find the lap time there," he said. "But with the Michelin I need to change a little bit the riding style.

"Today I was braking late but not like Bridgestone! I try to take some safety. But still I'm trying to learn how to ride with the Michelins, but also it looks like you need to change the balance of the bike and today I was riding completely the same like the race here."

While Honda seeks to get on top of the engine issues, it was no surprise that Marquez did not change the chassis.

"Today completely the same, as I used at the end of last year. Same bike, just the engine."

So your 2014 chassis?

"Yes."

Team-mate Dani Pedrosa was third fastest and the top Honda rider, but one-second from Lorenzo.

Testing continues on Tuesday and Wednesday.