Avintia's Hector Barbera is riding with a new pneumatic-valve version of the Kawasaki ZX-10R engine at the Misano MotoGP.

However the Spaniard felt he hasn't yet made the most of it, managing only 17th in qualifying.

"I am happy with the fact of having used for the first time the new engine but it has been a pity to not have been able to make the most of it," said Barbera.

"We have tested many things to adapt the settings to the response of the new engine but we have not succeeded.

"We have had a lot of chattering and that has not allowed us to be quick. It is a pity because the engine is better in all its range and I think that we can be very competitive with it, but today we have not been able to take advantage of it."

Although still to be refined, such a significant engine development suggests Avintia plans to continue with the FTR-Kawasaki package beyond the end of the current season, rather than switch to one of the new privateer machines from Honda and Yamaha, or the upgraded Aprilia package.

A Kawasaki factory team raced in MotoGP from 2002-2008, claiming four podiums before 'suspending' its MotoGP activities due to the financial crisis - a decision repeated by Suzuki at the end of 2011. Kawasaki used pneumatic valve technology on its own in-house ZX-RR prototype from 2007 until the end of the 'unofficial' Hayate project in 2009, although Avintia seems to have sourced the ZX-10R modifications.

"The benefits [of pneumatic valves] aren't just more revs, but the cylinder head is also lighter and that lowers the centre of gravity," Kawasaki (and now Marc VDS) communications director Ian Wheeler told Crash.net in 2008. "It's also smaller, so it allows for the position of the engine to be moved around more inside the frame."

Kawasaki engines returned to grand prix via the new privateer CRT class at the start of last season, which allowed the use of modified superbike engines. Avintia and Forward Racing currently use ZX-10R based powerplants in an FTR chassis.

Forward has concluded a deal to run privateer-spec Yamaha M1 machinery in 2014, but Avintia has yet to announce its plans and the engine upgrade suggests Kawasaki power could well continue at the Spanish team next season.

The 'claiming rule' is being phased out for the start of next year, to coincide with new prototype-based privateer machines from Honda, Yamaha and possibly Ducati. The relaxation of the rules means existing CRT entries will need to increase their performance to be competitive.

Aprilia has already confirmed that a pneumatic-valve engine and seamless shift gearbox is in the pipeline for its RSV4-based ART, which the class leading Aspar team is already confirmed as using.

Honda and Yamaha use pneumatic valves for their factory prototypes, while Ducati has its trademark Desmodromic valve system. The Honda Production Racer will not have pneumatic valves or a seamless shift gearbox in order to contain costs. However the Yamaha privateer package will use 2013 spec M1 engines, including pneumatic valves.

Privateer entries must use the full standard ECU system next season, but will have four extra litres of race fuel available and can make twelve rather than five engine changes during the year, relative to the factory bikes.

Update: Barbera continued to struggle with chatter in the race and retired as a result:

"Despite having used for the first time the new engine, we have not been able to obtain any advantage of it because of the problems we have had with the bike. It is true that I like the engine and it feels better, both in acceleration and speed, but the presence of an excessive chattering has deprived us of the chance of achieving a good result.

"During the race I have tried to minimise the problem by trying different ways to ride, but it has been impossible. The riding was increasingly more difficult and I have chosen to stop in my pit-box to avoid a possible fall. Tomorrow we have test and we have to find out what has happened."