Roberts breakthrough after Checa bike swap.

The final day of testing Sepang saw the unexpected sight of Kenny Roberts on a Honda RC212V and Carlos Checa on the former world champion's KR212V.

Honda, which supplies engines to Team Roberts, had promised the RC212V ride to help focus the independent team's chassis development at its first 800cc test. The LCR team then obliged, with its rider Checa also seizing the chance to briefly try the brand new KRV.

"For sure we learnt a tremendous amount today," said Kenny. "I've got to thank Honda because they promised me at Valencia last year that they'd let me ride one of their bikes here - because it was gonna be our first test. We did it at about one o'clock today and so thanks to Carlos Checa and his guys."

Although the subsequent progress didn't translate directly into lap times, Roberts ending the test 17th, many of his opposition ran qualifying tyres on Wednesday while the American gained half a second on race rubber - with much more possible.

"The problem [before the bike swap] was that in some of the fast stuff I'd been really fighting our bike and blistering my hands, but I'd just kinda thought it was either me or the line," explained Kenny. "But Carlos's bike was much more stable coming out of turn three and that kinda kicked stuff off for us to work in that direction. I was fighting it non-stop and my corner speed through there wasn't very good.

"So for the last hour we made some big improvements and for here darn-near fixed it completely," he revealed. "At first, we didn't really know how to fix it, we thought it was coming from the link and the shock. But to cut a long story short, it seems like we've made a big improvement. Laptime-wise, we weren't able to do much tyre testing for Michelin, but we did a low 2min 3secs on race tyres but I'm sure I could have been somewhere in the 2min 2secs if we'd worked at it. So we're at a good stage right now."

Meanwhile, Checa provided a less detailed analysis: "I swapped my bike with Kenny Roberts Jnr to gather data and to share our opinions on the engine."