Tonight I attempted to install a KDE 600XF-1100 in my E5, but I found that the with the pinion positioned to engage the main gear, the set screw for the pinion ends up just a little past the factory-machined flat spot. By my measurement, the flat spot needs to extend another ~4mm towards the motor (i.e. closer to the motor mount).
In the attached photo I've tried to line up the pinion to show where the set screw is along the shaft when the pinion is positioned at the right height to engage the main gear. There's a little bit of parallax in the shot, but hopefully you can get a sense of what I'm seeing.
Has anyone else found the same? Did you grind the shaft with a dremel to make a longer flat spot that will line up with the set screw?