i had alot of bad engagements before i shimmed , especially on the otherstarter. not to say this one isn't the culpret for rounding the teeth off.I don't think the gear will engage enough of the fly wheel teeth. Not deep enough into the teeth and not enough engagement. Move the starter closer to the flywheel and adjust in towards the flywheel for better engagement. What the hell did I just say? You can see how on the starter gear how the teeth are rouinding over from not getting a deep enough bite on the flywheel.
I've never had any luck with those little race starters that dont have a nose. Why not use one of these , just as light and no problems.
Oh, and if you buy one of the lifetime warrantied ones from Oriellys you can get it replaced in just about any town you go to, JMO