1984 honda 200es cam sprocket chewed up

[bruce]

This is my third sprocket. It seems to be more at the index mark on the sprocket. Checked the crank sprocket, no wear. Can the chain be stretched to were I can"t keep it in proper time? Anyone run into this? Any thoughts? Thanks Bruce

[Mudflap64]

I've heard that happens on some of the older Hondas. When they add the key and the index mark after casting the sprocket they would heat the area where the index mark goes before punching it. The heating would weaken that area of the sprocket causing it to wear prematurely. I'd suggest trying to find a fully machined steel sprocket. I'm no expert but i've heard that problem on the motorcycle engines too.