Originally Posted by
MudPie
I will add my $.02: it could be a stiff link in the chain, especially at the link with the new pin. Detention the chain by taking it off the chainring and ensure all links are free to flop around.
Good point, but there's an easier way to check for stiff links. shift into a middle gear where chain (sprocket) alignment is good.
Push the idler pulley forward so the lower loop sags forming a catenary. Backpedal slowly and watch as the chain emerges from the pulley. Look for any link(s) that doesn't immediately open into the same curve as it's neighbors.