I don't mind being shot down for this, here goes, I just seem to remember being advised not to grease the bendix on a starter motor.
Agreed - dirt and clutch plate dust sticks to the grease and makes the problem worse. But I remember a squirt of WD40 on the starter bendix of my Triumph Vitesse worked wonders when I had a similar problem years ago. I think powdered graphite or MoS2 was the recommended lubricant.
