With MotoGP's summer break halfway done, testing resumes later this week for some of the top names in the sport. Current and former champions take to the track at Brno and Motegi, with Yamaha, Honda and Suzuki all testing a range of material.

The most relevant test for this year's championship will be held at Brno, where Yamaha's Jorge Lorenzo and Valentino Rossi will be testing the factory M1s. Lorenzo's aim will be to test his collarbone, while Rossi continues to work on set up, chasing minor improvements to the major step forward made during the Aragon test. The Yamaha pair will also hope to be testing Yamaha's seamless gearbox at the two-day test, the first time that the factory riders will get to try out the new seamless transmission. So far, it has only been tested by Yamaha's test riders in Japan, working on reliability. Whether the Brno test means that the seamless gearbox will be ready for use later this season remains to be seen.

Over in Japan, Yamaha's test team, consisting Wataru Yoshikawa and Katsuaki Nakasuga, will be at Motegi, where they will be joined for a private test by Honda's test team and Suzuki. Motegi sees the temporary return of Casey Stoner to the MotoGP fold, where he will be replacing the injured Kousuke Akiyoshi. Stoner will be testing Honda's 2014 RC213V to be used by the factory team, and also continuing work on the Production Racer Honda is building as a replacement for the CRT bikes. Joining Stoner will be his former crew chief Cristian Gabarrini, an indication of just how seriously HRC are taking this test.

The return of Stoner to testing has spawned a veritable firestorm of rumors that the Australian is about to make a shock return to MotoGP. Repsol Honda team principal Livio Suppo stated when the test was announced that there were no plans for Stoner to race as a wildcard in 2013, though he made no comment on any plans for 2014. In an interview with GPOne.com, Gabarrini offers his opinion, that Stoner's return is only a reflection of his desire to ride the bike, and that he is unlikely to want to return to racing. One of the conditions of the test is that it will be done in private, with no media present, meaning that Stoner can just focus on and enjoy riding without enduring the questions of reporters.

Also present at the test will be Randy de Puniet, who will be continuing work on Suzuki's MotoGP machine. Development is still ongoing on the bike, with Suzuki's return to the series scheduled for 2015. Development is focused on extracting more performance from the engine and chassis, while waiting to start work with the spec electronics systems. Speaking to MotoGP.com, Suzuki team manager Davide Brivio explained that Suzuki is still using the Mitsubishi electronics at the moment, as Suzuki's engineers are still working on analyzing the spec Magneti Marelli ECU which all MotoGP bikes must use next year. The process of porting software from one system to the other is tedious and time-consuming, with existing algorithms having to be reimplemented for an entirely different system, and an analysis made of which algorithms need to be changed to accommodate the differing hardware specs and data inputs between the two systems.

How much news emerges from the tests remains to be seen. While Jorge Lorenzo and Valentino Rossi will doubtless be quizzed about the test once they arrive at Indianapolis for the Indy round of MotoGP, news of Casey Stoner's lap times will either have to come from official HRC press releases, or from spies at the test. With three teams present, there are more opportunities for such leaks to occur.