That's the starter clutch roller. It's a critical part. Your bike will not start or run correctly without it. Do not attempt to start the engine. You need to pull the primary cover and inner primary to reinstall it into the starter clutch assembly.

 

I admire how confidently you speak bullshit.

 

If so wondering how it would've ended up there starter wasn't removed and bike starts fine.

 

Also rollers are round, this is D shaped

 

And it looks to be missing half of whatever it is in the center pic.

 

That's the starter clutch roller. It's a critical part. Your bike will not start or run correctly without it. Do not attempt to start the engine. You need to pull the primary cover and inner primary to reinstall it into the starter clutch assembly.

That is ridiculous.

I suspect poster Roberto145 is not a real person, but a computer generated bot.

 

He definitely has a unique way of working on these bikes.

In addition to removing the inner primary to replace that flat-sided roller from the unserviceable starter clutch, you also need to drain and remove the fuel tank and pull the battery to make sure nobody tries to start the bike while you are working on it. You might even want to lock the fork in case they still manage to get it started.

Bob-o must be thinking of the newer bikes because of CAN bus that goes through the roller. Those bikes wouldn't start without it.

 

probably leftovers how they got there is a mystery...if yours is all good why worry