Hello, thanks all for your replies.
he bike is actually without fuel, and has not be used for 6 years.
Y cleaned the tank, and installed new punp, filters and hoses, despite other maintanance.
So, i'm ok to use the vacuum cleaner.
A guy from spain, suggsted me to fill the combustion chamber with oil, and then suck it, he believes that the debris will be ¨taken ¨by the oil...seems an interesting approach too.
But i'll start with the vacuum cleaner, and i'll build a filter, a cotton one, just to see if the debris was sucked...
I'll post the results, thanks all for your ideas!!
Fabian