I have a AKM21G that, according to the selection guide, should have a Back EMF constant of 6.6 (V/krpm) and a line-to-line resistance of 1.44 ohms, both with a +/- 10% tolerance. I had some problems and so I measured the line-to-line and got 1.8 ohms and empirically got 8.8 (V/krpm) for the back emf constant.
Both these numbers are around 25% higher than the published values. Is "AKM-Selection_Guide-en-US_RevB" the latest revision? Is this a known issue?