Riding of a MotoGP bike outside of a grand prix weekend by race riders is heavily restricted, so why are Valentino Rossi and Nicky Hayden able to test an early version of next year's Ducati GP12 at Jerez today (Friday) and tomorrow?

The answer is that the MotoGP testing restrictions - which allow two tests, after Estoril and Brno, during the season - only apply to "contracted riders with machines eligible for the MotoGP class."

The key word being 'eligible'.

That means if a MotoGP rider is on track with a bike they wouldn't be allowed to use during a race weekend, then they are not subject to the testing restrictions.

Clearly there is massive potential for this rule to abused.

Simply changing a minor part could make a bike 'ineligible for the MotoGP class' and allow unlimited testing by the race riders (non-race riders have less restrictions).

The FIM and MotoGP teams know this, of course, and a kind of gentleman's agreement keeps the MotoGP testing restrictions in place.

An example of this was when Rossi used a Superbike to test his race fitness after injuries. Yamaha (last year) and Ducati (this year) could have put him on a lightly-modified MotoGP bike had they wanted to dodge the rules.

However, the news that Rossi and Hayden are to ride an early version of next year's (1000cc) MotoGP Ducati is a new development.

It meets the letter of the law, since the 2012 bike is clearly not eligible for the present (800cc) MotoGP class - and may not, in its current state, be eligible for the 2012 class either.

But if testing such a 'future' bike is fine, can all manufacturers (or CRT teams from next year) use that excuse from now on?

Could they argue that 2011 has shown in-season testing restrictions only apply to current bikes and that it is within the rules for race riders to test with an 'ineligible' version of the following year's bike?

And what if Rossi and Hayden were to use the Jerez GP12 test to also try some parts that could be used on this year's bike?

Even if FIM officials monitored the test, where would they draw the line between information useful for 2011 and information only for 2012?

The reality is that Ducati has probably got the go-ahead from the other manufacturers for the Rossi/Hayden 1000cc test, and the MSMA (manufacturers' association) may even have already agreed to a certain number of such extra track days to develop next year's bikes.

That would be a sensible solution, since all the factories will need input from their race riders for the new breed of MotoGP machines, but it does seem to circumvent the (perhaps deliberately vague) FIM regulations.

For comparison, the FIA's Formula One testing regulations are more precise, applying to "...any track running time undertaken by a competitor entered in the Championship..."

A multi-team 1000cc MotoGP test is expected to be held after the Italian Grand Prix at Mugello.