The second day of MotoGP testing at Sepang turned out to be Motor Monday. Four of MotoGP’s six manufacturers dedicated their day to gathering the data to make a decision on their 2018 engine.

All of them have the lessons of 2017 in mind, when the rule on sealed engines caught Suzuki out completely, and Honda to a lesser extent. Make the wrong choice in testing, and you have nineteen races to spend regretting it, much as Suzuki did last year.

The difficulty factories face is that the testing tracks early in the year are ideally suited to camouflage potential problems. Sepang is fast and wide, with relatively few very slow corners to test just how aggressive an engine might be. It is also almost as hot as the surface of Venus, which saps power and tames the engine.

Buriram replaces Phillip Island as a test track this year, but neither is conducive to teaching anything. Phillip Island is fast and flowing, and easy to go fast on. Buriram is stop and go in a heat even fiercer than Sepang, making a nonsense of engine assessment.

There’s the Qatar test, of course, but if you finally figure out what is wrong with your engine at Qatar, you have two weeks to fix it before the start of the season. That is not something that is ever going to happen, even in an ideal world.

So Monday was designated as engine day for the MotoGP teams, factory riders making a concerted effort to discern whether the engineers had found the correct direction for development.

It looks very much like that is the case for Ducati, Honda, Suzuki, and Yamaha. Ducati, Suzuki, and Yamaha confirmed that the new engine is better than their old ones, and have laid their worries to rest.