Casey Stoner had his first run on the 1000cc Honda that the team is building for the 2012 rules at Jerez today.
The Australian completed 50 laps on the machine, which has already been tried by test riders Kosuke Akiyoshi and Shinichi Ito at Suzuka. MotoGP manufacturers are allowed eight additional days of testing this year with their 1000cc machines.
"Everything has gone very well, very positive," said Stoner. "It's just nice to ride the 1000cc again, to feel the engine and the power. I had a lot of fun, I enjoyed the first day because everything we've tried seems to be working, so no complaints.
"We didn't focus on anything special today, just tried to understand what the bike is doing, how it reacts on the brakes and things like that, also considering some the issues we have with the 800cc right now.
"The braking point seems to be stronger, stability in the front going into the corner seems to be very good and, of course, we want to understand how the power delivery is, and it is very smooth so no problem. In general, we haven't changed too much from the setup we have on the 800cc right now and the feeling is very similar, so it's pretty good."
He admitted it was a shame that his teammate Dani Pedrosa had not been able to join the test as he recovers from the broken collarbone he sustained in a collision with Marco Simoncelli at Le Mans.
"The biggest disappointment is that Dani is not going be here to test as he is important to the development of this bike," said Stoner. "I hope that soon HRC can get his input as well because we need as much data as possible, in order to be ready for next season."
Pedrosa is yet to decide whether to have surgery on the injury or allow it to heal naturally.