dc42:
You must have been measuring the output with little or no load. Try measuring the output with the motor connected, and measure it directly across the motor terminals (i.e. between the two H-bridge outputs).Running a motor above its nominal voltage under light load will not harm it. What you need to avoid is prolonged running with the motor stalled or under heavy load, because this will burn out the motor or the H-bridge.
You were right, the measurement was made with no load. I measured acros output 2 and 3 (the ones that go to the first motor...) I got 1.6V with the voltage regulator....
I used 4xAA batteries and got 2.6 V on the motors. With no load the batteries showed 5.6V (guess they're a little used ?).
If the L298 has a 1.8 to 3.2V drop... isn't that going to deliver between 2.8 and 4.2V to the motors ? While 2.8 is acceptable.. 4.2 does not make me verry comfortable...
By using 4.5V I get the same 1.6V on the motors... So ... this means I get 2.8 - 3V drop on L298?
I should've paid more attention to the voltmeter... 