Double British Superbike champion Shane Byrne has finished the Portimao World Superbike test on top after steering his Sterilgarda Go Eleven Ducati to a best lap time of 1min 43.6sec on Wednesday.
Shakey, who lifted his second BSB title on a 1098 this season, was able to put his ex-Biaggi/Xaus bike 0.3sec clear of reigning triple AMA Superbike champion Ben Spies and also dipped under the fastest race lap in Sunday's season-ending WSBK event.
Ducati's departing triple WSBK champion Troy Bayliss had set a best lap of 1min 43.787sec on his way to completing a dream double victory, although track conditions had improved since the race.
Byrne made a rapid improvement in pace from his Tuesday best of 1min 45.0sec, while Spies - fastest of all on Tuesday - went 0.1sec faster after spending Wednesday on the 2009 R1, which features an uneven firing 'big bang' type engine design.
Max Biaggi finished his first official test for Aprilia, after a private shakedown at Valencia, a promising third fastest on the RSV4.
The Roman, seventh in the 2008 standings for Sterilgarda, improved by an impressive 1.3sec over the two days to finish just 0.2sec from Spies and 0.5sec from Byrne. Biaggi also lapped 0.674sec inside his best Portimao race lap with the Sterilgarda Ducati.
Fourth fastest was BSB race winner Tom Sykes, who put the second Yamaha Motor Italia R1 0.4sec from Biaggi and 0.9sec from Byrne. Sykes, like team-mate Spies, spent the second day of testing working exclusively with the '09 bike.
Yamaha's Japanese Superbike champion Katsuyuki Nakasuga matched Sykes' best lap time, while Alex Polita was ranked sixth, exactly one second slower than new team-mate Byrne.
Leon Haslam matched Polita's time on his Stiggy Honda debut. The BSB frontrunner lapped 0.3sec behind his best race lap on a HM Plant Honda, but 0.4sec faster than team-mate Roberto Rolfo.
Meanwhile, unsigned former WSBK race winners Regis Laconi and Lorenzo Lanzi both appeared for DFX Honda. Laconi set a best lap time of 1min 45.4sec, almost one second behind his fastest PSG-1 Kawasaki race lap, while Lanzi faced an even tougher task in switching from two- to four-cylinders and was a further 0.9sec slower.
Among those absent from the Portimao test were Ten Kate Honda, Alstare Suzuki, Ducati Xerox and the new BMW team (which chose to test in private at Valencia).