Although Rossi and Factory Yamaha team-mate Colin Edwards finished the final day a little earlier than usual, both completed their full agenda of work, once again trying several new tyres for Michelin, with Rossi also concentrating on improving the balance of the bike when braking.
Rossi's best time of 2mins 0.936secs was set on a qualifying tyre and is close to his pole position time from last year's grand prix, when he was riding the old 990cc machine. The Italian's nearest rival was Suzuki's John Hopkins, fastest on the opening two days, who clocked a time of 2mins 1.026secs. Edwards, who did not use a qualifying tyre, was eighth fastest with a lap of 2mins 2.266secs.
"Today was another good day for us," declared Rossi at the end of testing. "We concentrated a lot on braking and definitely made some improvements, although I think we can still make it even better and this is something we will work on when we come back here. We had an important technical meeting today and came to some interesting conclusions, which will help Yamaha's engineers to continue to improve our new bike. We've got through our entire programme for this test, including testing many new tyres for Michelin.
"Today I also had the chance to try a qualifying tyre and I was able to go below 2.01; I think that Michelin have done a very good job over the winter. We tried the 16" tyre again and I am still sure that it's good for us, although we still need more time to work on it with Michelin. Overall it's been a very positive test for us."
But whilst most teams will now head straight to Phillip Island for another test, Yamaha has instead elected to miss the Australian outing and instead return to action for the third and final Sepang test on 5th, 6th and 7th February.
"Most of the other teams will go to Phillip Island now, but we will return here in ten days with more new things to test," confirmed Rossi. "We still need to work on the engine, although for this early stage it's very good. So far we have concentrated on power delivery, rather than on the power itself, but this is only the first test of the year so there is plenty more time!"
Edwards also left Malaysia with a smile on his face, having solved his day two concerns by adopting a set-up similar to his team-mate's.
"I'm heading home feeling really happy after three excellent day's work. We didn't do so much today, 22 laps, but it was enough to back up what we've learnt this week and finish feeling sure about everything. We changed direction with tyres a bit today and went towards the package Valentino's been using and that definitely improved things even more; my fastest lap was on a race tyre similar to the one he's been using quite a bit," said the Texan. "We didn't try a qualifier, but I really felt that I got into the 'zone' on the race tyre and that was when my best time came. We tried a new front and a new rear as well and they were both great, the tyre situation in general is really good. We played around a bit with the setting too and tested a few things Valentino's been using, but actually I preferred my setting so we came back to that. So that's it for the first test and it's been really encouraging. A quick rest now and then we'll be back for more!"
"The final conclusion of this test is very positive but we need to keep working hard; we have clear ideas about what we need to do," added team director Davide Brivio. "We're coming back here again soon and we will have new items to test, especially tyres, and we will be able to continue to fine-tune the set-up of the new 800. 10th March is getting closer and closer so we have to just keep on working!"
