Chain tighter in one spot

As the wheel is turned the chain will become very tight and make a noise in one spot. Continuing the rotation will loosen the chain again until it reaches the same spot. Alignment marks on both sides are in the same position, and visually there seems to be no problem. Chain is well lubricated, and the sprocket does not seem to have a high spot. thanks Don

this is very common. u have a stretched section in your chain.
the best advice is to replace the chain and both sprockets at the same time.

That's how chains tell us that they have gone to chain heaven and need to be replaced....

Don, A little of this, a little of that. Chains develop "tight spots" the causes are various. The most common being setting for prolonged periods. the area where the chain encircles the c/s sprocket rusts in place.& can usually be discerned by a "hoop" visual in the "long run" between sprockets.(where tight spot occurs) So far, this is just a chain issue. for grins, rotate rear wheel til chain is "slack". then attempt to pull chain away from rear sprocktet "about the middle of rear of sprocket". if you discern "Any" slack, or visual wear of teeth on sprocket, it's time for a "set". depending on how "cheep" you are, a "Kinked" chain may be salvaged by soaking in solvent/kerosene/pepsi & use. Again , for "grins" feel a couple of "rollers" The cylinders within chain links which contact the valleys of sprockets, they should spin freely, but have no discernable "play". if no wear to sprockets but "play" exists, Rec. install a cheep "new non-oring" chain, & ride,,,, If adjustment becomes an issue, replace with a "quality set". Bikes of our vintage/use seldom see the demands placed upon them when new. (which in the day was @ 20 K) I converted to 530 @ 5k miles ago, & have made 2 minor adjustments. (abet w. steel sprockets & renthal O ring chain) just my 2 cents...G