(part 3) starter relay! Adam or another bike genius required!?

ive replaced the starter motor and its working. but inside the crank case the part next to the little cog that turns next to the starter motor (and i maybe wrong with the name) the starter benidix? sounds like its getting stuck or struggling to turn sometimes? if i have the crank case off it spins fast but falls out, but when i put the crank case back on it sounds like its struggling on getting stuck. could it just need abit of grease on each end of it or is it dammaged? would be good to get a reply off adam as he has been following me on this, but if not other suggestions are greatly welcomed. thanks in advance for any help given.