To you that insist the front sprocket can only be checked by pulling off the cover....there is a way...not a good one but a way. This inspection requires NO tools. Lay on your back with the bike on a service stand. Look along the chain line into the rear of the case cover and you can see part of the sprocket teeth. With a flashlight, look at the sprocket teeth while slowly turning the rear wheel. Look for the tip of the teeth to have a thin flat machined spot, every single tooth. If the teeth look like they have sharp edges....you have a worn sprocket worthy of checking better by pulling the cover. If you see a broken tooth....done deal, replace the sprocket ASAP.
Do not only look at the rear sprocket, the front wears 2 to 3 times as fast.