Jorge Lorenzo began working through a range of updates on offer from Yamaha, including a revised engine specification, during day one of the second Sepang MotoGP test.
But slippery track conditions, then an afternoon rain storm, meant the 2010 world champion was forced to delay any firm decisions until day two.
“We started with a different engine spec to the one we used in the last test,” confirmed Lorenzo, who finished the day in third place, behind the factory Hondas of Casey Stoner and Dani Pedrosa.
“Today it was difficult to make any comparisons as the track was in much worse condition than last time and the lap times were much slower. The rain also meant we couldn't finish everything.
“I didn't ride in the rain because we have so many tests to do tomorrow and I didn't want to risk anything.”
Speaking about the current strengths and weaknesses of the 1000cc M1, Lorenzo explained:
“The strong point of this bike is in corner speed, which is quite high, and corner entry. We still don't have the perfect corner exit yet and we must work on that with the engine, electronics and chassis. We need a more stable bike in acceleration.”
Chatter was less of a problem for Lorenzo than at the previous test, but the Spaniard felt there was a simple explanation.
“I had less chatter today, maybe because there was less grip from the track. But I'd prefer to have the chattering and go two seconds faster!” he smiled.
Team-mate Ben Spies was directly behind Lorenzo in fourth place.