With the 2013 MotoGP season at its halfway mark, now is a good time to take a look back and examine the engine usage for the teams and riders. In 2012, with the engine durability regulations in their third full season, the factories appeared to have the situation pretty much under control. The only excitement arose when something unexpected happened, such as Jorge Lorenzo have an engine lunch itself after he was taken out by Alvaro Bautista at Assen last year.

For 2013, the engine allocation was reduced from 6 to 5 per season. Each rider now has 5 engines to last the entire season, for use in all timed practice sessions during each race weekend. With three seasons already under their belt, no real drama was expected, yet that is not quite how it has turned out. While Honda and Ducati are right on course to last the season, Yamaha find themselves unexpectedly struggling. An unidentified design flaw has seen Yamaha losing engines too rapidly for comfort. Both factory Yamaha men have had an engine withdrawn, while there are question marks over the life left in one engine each allocated to Valentino Rossi and the two Monster Tech 3 Yamaha riders.

The trouble started for Yamaha with Jorge Lorenzo's #1 engine. That showed a problem at Jerez, clearly down on power to the other engine in use. The engine was withdrawn from Lorenzo's allocation and sent back to Japan for examination and testing, though Yamaha kept the fact that the engine had been withdrawn from both the media and from Lorenzo himself. Once an engine is active - in practical terms, once it has been sealed and leaves the pit lane for the first time - it cannot be run anywhere except for at races. The engines have either inlet or exhaust ports sealed by the Technical Director's staff at the end of each MotoGP event to prevent this from happening, and so by testing the engine, Yamaha had to breach the seals and withdraw it from Lorenzo's allocation. Lorenzo was not told until two races later, Yamaha not wishing to distract the reigning world champion from the defence of his title. Yamaha have a history of misleading Lorenzo, offering soothing words to give the Spaniard time to calm down and come to terms with an unpleasant reality. A previous example came last year, when Lorenzo lost an engine at Assen, and Yamaha allowed him to believe that Race Direction would give him an extra engine, in clear contradiction of the rules. By the next race, at the Sachsenring, Lorenzo had accepted his lot, and understood that he would not after all be given an additional engine.

Though his #1 engine has been withdrawn, Lorenzo's engine allocation is now more or less back on track. His #2 engine is now nearing the end of its life, while engines #3 and #4 still have plenty of sessions left on them. There may be some juggling required, but Lorenzo should make it to the end of the season without being forced to take an extra engine and suffer a penalty. If, that is, he suffers no mishaps like the one at Assen last year.

Valentino Rossi, meanwhile, appears to be in a little more trouble. Rossi had his number two engine withdrawn after Mugello, though that engine already had 28 sessions on it, and was coming to the end of its useful life. His #1 engine is more of a cause for concern. That hasn't seen action since Mugello either, and though it is still officially available, Rossi has shown no sign of using it. Having been used in just 18 session, it is too early for that engine to be withdrawn altogether, and Rossi has been racking up the miles on his #3 and #4 engines, with 27 and 23 sessions on them respectively. At the halfway point in the season, things are looking worryingly tight for Rossi.

Then, of course, there is the question of Yamaha's seamless gearbox. The gearbox is to be tested at Brno this week, and if both Rossi and Lorenzo approve, the factory Yamaha men will use the new gearbox some time before the end of the season. The big question is, will the seamless gearbox require a new engine to be taken, or can it be retrofitted to the existing M1 engine. Depending on the technology used, a seamless gearbox is physically larger than a conventional one, with the mechanism allowing two gears to be selected at the same time taking up more space than the traditional arrangement. Will that extra functionality demand new cases, and therefore a new engine, or can the new gearshift be shoehorned into the existing cases? The third possibility is that Yamaha has been using the gearbox housing for the new seamless transmission since the beginning of the year, but have adapated their conventional transmission to use the new cases. We shall see soon enough; once Yamaha starts using the seamless gearbox, we should be able to to tell if all of the Yamahas use it, or just a single bike for each of the four men on a YZR M1.

While the problems appear to be larger in the factory team, Cal Crutchlow and Bradley Smith also need to tread carefully. Crutchlow appears to be in the best shape of the Yamaha riders, with one engine with 30 sessions currently shelved, but three more in use. Bradley Smith, however, has also had one engine with few sessions set aside, his #2 engine not having been on track since Mugello, and having racked up just 16 sessions, rather than the 35+ which are necessary to make it to the end of the season.

The contrast between the predicament of Yamaha and the comfort of Honda could hardly be greater. Of the four Honda riders, only Alvaro Bautista has had an engine withdrawn, his #2 motor having had its seals broken after Assen, with a healthy 38 sessions on it. All four Honda men still have two engines which have not yet been used, with just three engines each in play. And for all four Honda men, the #3 engines have barely seen much action at all, engines #1 and #2 having racked up serious mileages. Only Honda has managed to extract more than 40 sessions out of their engines, with Dani Pedrosa and Marc Marquez having one engine each with over 40 sessions, and Stefan Bradl having two such power units. It can hardly come as a surprise that HRC should be managing their engines so proficiently: the engineering genius of Honda saw them get it right first time, with Dani Pedrosa using just five engines in the first season of engine limits, in a period when six were allowed. Only sabotage or alien invasion will prevent Honda from making it to the end of the year with miles to spare on their engines.

Much the same could be said of Ducati. Though all four Ducati riders have had engines withdrawn, the situation is still well in hand. Nicky Hayden, Ben Spies and Andrea Iannone all have low mileage on their #3 engines, helped in the case of both Spies and Iannone by missing events through injury. Andrea Dovizioso's #3 engine is a little more used, but with 18 sessions on it, there is still plenty of life left in them. The Ducati engines appear to be able to reach 35+ sessions with relative ease, where Yamaha struggle to make 30 sessions with each engine.

Ducati's engine situation means that all four men still have two engines each left. Ducati are known to be working on a larger upgrade to the Desmosedici, and though the frame has been the main focus of design, there is some speculation that the engine may be modified at some stage this year to make it more compact, though the 90° angle between the cylinder banks will remain. If Ducati do debut a modified engine, all four Ducati men could test it at Misano, before using them for the final five races of the season.

Looking at the CRT bikes, it is clear that they, too, are improving in their engine usage. A lot more CRT engines have been withdrawn, but only the situation of Hector Barbera is actively worrying, the Avintia Blusens rider having already had half his engines withdrawn from allocation.

What is also clear from the CRT engine allocation lists is that the Aprilia in its current state is incapable of making an entire season with just 5 engines. The current rules would allow Aprilia 9 engines, were they to return to MotoGP as an MSMA entry, and that seems a more achievable goal. Both Karel Abraham and Yonny Hernandez appear to be on target to make the season with 9 engines, though they may still use 12 this year. The Aspar pairing of Aleix Espargaro and Randy de Puniet, both with heavy support from Aprilia, are having a little more trouble. De Puniet is looking the more comfortable of the two, having used just 6 of his engines to Espargaro's 7, though De Puniet has had one more engine withdrawn. The question is, of course, whether Aprilia really are trying to make it to the end of the year inside of the limit which they will face next year, if they decide to race as an MSMA entry. That, too, will be clear soon enough.

Below is the full list of engine usage for each rider, with the sessions and races used on each engine. At the bottom follows a legend, explaining the various statuses and what is meant by a 'session'.

Honda

26 Dani Pedrosa Repsol Honda Sessions Races Status Engine #1 38 4 Shelved Engine #2 46 3 Active Engine #3 5 1 Active Engine #4 0 0 Unused Engine #5 0 0 Unused

93 Marc Marquez Repsol Honda Sessions* Races* Status Engine #1 39 3 Shelved Engine #2 42 4 Active Engine #3 8 1 Active Engine #4 0 0 Unused Engine #5 0 0 Unused

* The engine usage chart for Marc Marquez was not complete, missing both warm up and the race from Laguna Seca

6 Stefan Bradl LCR Honda Sessions Races Status Engine #1 40 4 Active Engine #2 49 4 Active Engine #3 11 1 Active Engine #4 0 0 Unused Engine #5 0 0 Unused

19 Alvaro Bautista Gresini Honda Sessions Races Status Engine #1 39 4 Active Engine #2 38 4 WFA Engine #3 12 1 Active Engine #4 0 0 Unused Engine #5 0 0 Unused

Yamaha

46 Valentino Rossi Yamaha Factory Racing Sessions Races Status Engine #1 18 0 Shelved Engine #2 28 3 WFA Engine #3 27 3 Active Engine #4 23 3 Active Engine #5 0 0 Unused

99 Jorge Lorenzo Yamaha Factory Racing Sessions Races Status Engine #1 17 2 WFA Engine #2 32 1 Active Engine #3 19 3 Active Engine #4 10 2 Active Engine #5 0 0 Unused

35 Cal Crutchlow Tech 3 Yamaha Sessions Races Status Engine #1 30 3 Shelved Engine #2 22 1 Active Engine #3 21 3 Active Engine #4 15 2 Active Engine #5 0 0 Unused

38 Bradley Smith Tech 3 Yamaha Sessions Races Status Engine #1 31 3 Active Engine #2 16 0 Shelved Engine #3 19 4 Active Engine #4 7 2 Active Engine #5 0 0 Unused

Ducati

4 Andrea Dovizioso Factory Ducati Sessions Races Status Engine #1 27 4 Active Engine #2 34 2 WFA Engine #3 18 3 Active Engine #4 0 0 Unused Engine #5 0 0 Unused

69 Nicky Hayden Factory Ducati Sessions Races Status Engine #1 30 6 Active Engine #2 35 2 WFA Engine #3 11 1 Active Engine #4 0 0 Unused Engine #5 0 0 Unused

11 Ben Spies Pramac Ducati Sessions Races Status Engine #1 32 2 Active Engine #2 28 3 WFA Engine #3 13 2 Active Engine #4 0 0 Unused Engine #5 0 0 Unused

29 Andrea Iannone Pramac Ducati Sessions Races Status Engine #1 30 5 WFA Engine #2 38 1 Active Engine #3 4 1 Active Engine #4 0 0 Unused Engine #5 0 0 Unused

CRT Bikes

14 Randy de Puniet Aspar ART Sessions Races Status Engine #1 11 1 WFA Engine #2 18 3 WFA Engine #3 18 1 Active Engine #4 17 1 Active Engine #5 1 0 WFA Engine #6 5 3 Active Engine #7 0 0 Unused Engine #8 0 0 Unused Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

41 Aleix Espargaro Aspar ART Sessions Races Status Engine #1 15 0 Active Engine #2 9 1 WFA Engine #3 17 1 WFA Engine #4 7 2 Active Engine #5 17 2 Active Engine #6 4 2 Active Engine #7 3 0 Active Engine #8 0 0 Unused Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

17 Karel Abraham Cardion AB ART Sessions Races Status Engine #1 15 2 WFA Engine #2 9 0 WFA Engine #3 18 1 WFA Engine #4 19 2 Active Engine #5 6 2 Active Engine #6 0 0 Unused Engine #7 0 0 Unused Engine #8 0 0 Unused Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

68 Yonny Hernandez PBM ART Sessions Races Status Engine #1 7 1 WFA Engine #2 22 1 WFA Engine #3 11 1 WFA Engine #4 15 2 WFA Engine #5 9 2 Active Engine #6 10 2 Active Engine #7 0 0 Unused Engine #8 0 0 Unused Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

70 Michael Laverty PBM Aprilia Sessions Races Status Engine #1 9 0 WFA Engine #2 25 1 Active Engine #3 13 3 WFA Engine #4 17 3 WFA Engine #5 2 0 WFA Engine #6 7 1 Active Engine #7 2 1 Active Engine #8 0 0 Unused Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

5 Colin Edwards NGM Forward FTR Kawasaki Sessions Races Status Engine #1 16 2 WFA Engine #2 7 1 WFA Engine #3 19 1 WFA Engine #4 26 5 Active Engine #5 6 0 Active Engine #6 3 0 Active Engine #7 0 0 Unused Engine #8 0 0 Unused Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

71 Claudio Corti NGM Forward FTR Kawasaki Sessions Races Status Engine #1 14 2 WFA Engine #2 17 1 WFA Engine #3 4 1 WFA Engine #4 13 2 Shelved Engine #5 16 1 Active Engine #6 2 0 WFA Engine #7 11 2 Active Engine #8 0 0 Unused Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

7 Hiroshi Aoyama Avintia Blusens FTR Kawasaki Sessions Races Status Engine #1 9 1 WFA Engine #2 11 2 WFA Engine #3 13 0 WFA Engine #4 14 2 WFA Engine #5 4 1 Shelved Engine #6 4 2 Active Engine #7 10 1 Active Engine #8 0 0 Unused Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

8 Hector Barbera Avintia Blusens FTR Kawasaki Sessions Races Status Engine #1 21 3 WFA Engine #2 4 0 WFA Engine #3 1 0 WFA Engine #4 7 0 WFA Engine #5 9 1 WFA Engine #6 5 1 WFA Engine #7 13 2 Active Engine #8 10 2 Active Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

67 Bryan Staring Gresini Honda FTR Honda Sessions Races Status Engine #1 18 3 WFA Engine #2 7 0 Active Engine #3 28 4 Active Engine #4 21 2 WFA Engine #5 0 0 Shelved Engine #6 0 0 Unused Engine #7 0 0 Unused Engine #8 0 0 Unused Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

9 Danilo Petrucci IODA Racing Suter BMW Sessions Races Status Engine #1 12 1 WFA Engine #2 14 1 WFA Engine #3 6 1 WFA Engine #4 10 1 WFA Engine #5 14 1 WFA Engine #6 12 2 Active Engine #7 10 1 WFA Engine #8 3 1 Active Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

52 Lukas Pesek IODA Racing Suter BMW Sessions Races Status Engine #1 15 2 WFA Engine #2 2 0 WFA Engine #3 4 0 WFA Engine #4 14 1 WFA Engine #5 12 2 WFA Engine #6 18 3 Active Engine #7 5 0 Active Engine #8 2 1 Active Engine #9 0 0 Unused Engine #10 0 0 Unused Engine #11 0 0 Unused Engine #12 0 0 Unused

Legend

Sessions: The number of sessions an engine has been used for. Sessions include free practice, qualifying practice, warm up and races.

Races: The number of races an engine has been used in.

Active: The current engine is still in active use. It was used in the last two races, and is likely to be used again in the coming races.

Unused: The engine has not yet been used. To be specific, the engine has not yet been sealed and exited pit lane. There are no restrictions on the engine (other than using the same bore and stroke as the previous engines) before it is sealed and used.

WFA: Withdrawn from allocation - the engine seals have been broken, and the engine is deducted from the allocation. The physical engine may be reused, but new seals must then be applied, and it will be regarded as exactly the same as a new engine as far as the rules are concerned.

Shelved: This is the only "unofficial" status. We are calling "shelved" all engines which have at one point already been active, but have not been used for at least two races. Usually, these engines have been used extensively, and are being kept back as reserve items, in case the rider starts having trouble with his engine allowance.