A wee update - I fitted the spare starter motor (same part no. 9 tooth Bosch) and unsurprisingly it's fine. So that's good. But since I'm probably going to keep this bike I'd like to have a usable spare so I'll probably take the original starter apart again. There are two things I'll pay attention to - lubing the Bendix again for longer this time and pressing the cone end bearing/bush back in flush to the housing as it had come forward about 1mm towards the inside (see photo - brass colour). Only noticed this when comparing the two starters.
Just looked at Motobins and surprisingly you can actually buy a new Bosch Bendix if you want to part with 40 quid. With a couple of new end bushes - could be the answer. That would involve taking the Bendix off - more complicated. Has anyone done this before?
Edit - Bendix removal described in this link - as Bob said 2nd page of the Technical FAQ's, sorry Bob hadn't looked at this...
http://www.thisoldtractor.com/moto_guzzi_loopframe_starter_and_solenoid_repair_-bosch-.html
