Thank you all for the explanations...I'm trying to summarize.
-I have a good idle speed and the bike runs perfectly.
-The maintenance, as far as I can and know, is done by me and I have never had any problems and the motorcycle has not suffered a blow, fall, etc... I summarize the current fault:
-Idle well in neutral, whether hot or cold.
-I hold the clutch lever and idle ok.
-I engage 1 gear and the rpm rises more than normal (+- 2000/2500 rpm) (clutch lever in the same position as the previous point)
-I release the clutch lever and it circulates without problem.