For the history:
I went to my mechanic. We checked and corrected-if it was necesary- the valve clearances (.10 intake, .15 exhaust).
We followed step by step the forum's procedure about TB balance and TPS set.
Finally, I went for a ride to check the bike and I concluded that the .521 mV (TPS 150 mV when rod off) is not so good as it was my previously 440mV (2.8 degrees).
Conclusion: when the TPS was at about 140 mV (with the key on, rod off) and 2.8 degrees/about 440mV (key on, rod on, engine off) (3.0 degrees-engine running) (and with the certain position of jupiter, aphrodite, andromeda and moon), the bike was running perfectly. I had the feeling that all the available power was going down on the rear wheel. So I reset the TPS from .521 to 440 mV (140mV/rod off).
Now I think I am ready to go for a custom map.