I checked the following items:
1) diag: run the fan through the diag screen (Zone 51): works fine.
2) diag: the fan is coming on at the correct temp around 105C on the dash (zone 06): works fine.
3) my radiator cap has no date stamp. But it looks like the old one. (The bike is 2005 model)

The cap is leaking when the temp is above about 95-100 degrees. So the problem is a faulty radiator cap.

Tomorrow i order a new one, that must solve the problem.

Thanks Kev..