YAMAHA have blamed MotoGP’s new spec electronics for the engine failures suffered by Valentino Rossi and Jorge Lorenzo on race day at the Italian Grand Prix.

Both factory M1s suffered very public engine failures on Sunday at Mugello; Lorenzo’s occurring with a couple of minutes to spare in the warm-up, while Rossi’s happened on the eighth lap of the race.

Yamaha issued a statement on the eve of this weekend’s Catalunya Grand Prix, making it clear that the failures were down to the electronics — which are identical Magneti Marelli-supplied units to all bikes in 2016 — rather than their engine itself.

“To be clear, there was neither an engine component nor a structural failure, it was purely an electronic control issue,” Yamaha’s MotoGP project leader, Kouji Tsuya, said in the statement.

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“The failures were caused by an electronic issue related to the rev limiter which ultimately resulted in valve and piston damage.

“The cause for both Jorge’s and Valentino’s engine failures was the same.”

The trigger point was the crest at the end of Mugello’s fast front straight, causing the bikes to briefly lift off the track while doing 350km/h and at maximum revs.

“The engines had no problems, but we were not aware of the different behaviour of the standard ECU software, that made the rev limiter work in a different way compared to last year,” Tsuya said.

Yamaha say they have made adjustments to the rev limiter settings for Catalunya this weekend.

“We have already devised a countermeasure, so we are confident that the failures in Mugello will not recur,” Tsuya said.

Neither Lorenzo nor Rossi will use their blown engines again this year. Source: AFP

BLOWN ENGINES WITHDRAWN FROM ALLOCATION

The engines blown were both the third of the seven engines Rossi and Lorenzo are allowed to use throughout the season.

The magnitude of the blow-ups mean both engines have been withdrawn from each rider’s allocations and will not be used for the rest of the season.

Incidentally, Lorenzo’s third engine had completed more sessions than Rossi’s engine. Both riders used their No. 3 engines for the first time in FP3 at Jerez and would use them in ever session for the rest of that weekend.

But while Rossi’s engine would only be used again on race day at Le Mans and Mugello, leaning on his No. 1 engine during practice and warm-ups, Lorenzo’s also saw use during practice at both events.

Yamaha are confident that both riders still have more than enough engines to complete the season without accruing penalties.

Rossi was poised to battle Lorenzo for the win prior to the failure; Lorenzo won the race with his No. 2 engine. Source: AP

THE FULL STATEMENT FROM YAMAHA

Kouji Tsuya, 2016 Yamaha YZR-M1 Project Leader

After the technical problems in Mugello the two defective engines were returned to YMC for investigation. Following our detailed investigation of the engines, telemetry data and related systems we found the cause of the failures.

The failures were caused by an electronic issue related to the rev limiter which ultimately resulted in valve and piston damage. The cause for both Jorge’s and Valentino’s engine failures was the same.

To be clear, there was neither an engine component nor a structural failure, it was purely an electronic control issue.

Valentino’s failure was caused by an accidental over rev in acceleration that occurred jumping over a crest with full throttle at the end of the straight. This failure was not in any way related to the mistake made by Valentino at the San Donato corner on the lap before.

There were no special mapping settings used for Mugello; we used the same precise mapping as always. We have now withdrawn both engines from the allocation for the season.

We have a strong history of engine reliability and this fact does not change after this incident; the engines had no problems, but we were not aware of the different behaviour of the standard ECU software, that made the rev limiter work in a different way compared to last year. We set the rev limiter using last year’s data in exactly the same way as we did last year, but we could not be aware that the software worked in a different way.

Valentino’s engine was the freshest of the three that were sealed so far from his allocated engines, therefore after Jorge’s Warm Up engine failure there was no reason to consider replacing it. Furthermore we couldn’t find out the electronic issue in Jorge’s engine in such a short timeframe.

Mugello is one of the most critical circuits because of jumping over a crest with full throttle on the straight, and engine RPM becoming higher. We have learnt from this incident and already modified the rev limiter setting, so it will be OK in Catalunya. As a precautionary measure, the other engines used by both Valentino and Jorge in Mugello will be used only for practice sessions, until their life cycles are completed.

We understand an electronic issue caused the failures in Mugello, therefore we do not need to intervene with our remaining engines that are not yet sealed. We still have enough engines for the remainder of the season. We have already devised a countermeasure, so we are confident that the failures in Mugello will not recur.