Originally Posted by
The_Joe
Well I tightened up the chain wheel and the arms but it's still making noise. Next I'll try tightening up the chain a bit and failing that I'll revisit the bottom bracket.
If this is a single speed
the chain should NEVER be under under tension. Perhaps this is your problem.
Chainrings, especially steel cottered crank chainrings are always a bit eccentric. That means that the tension will vary as you pedal. The correct adjustment is that whereby the chain still is slightly slack at the tightest position.
Rotate the cranks with a finger pushing the the middle of lower loop up slightly and feel where that the chain is tightest (most straight against finger pressure). At that point the there should be enough slack for the middle of the lower loop to freely move up or down 1/8" or so (min,). Or you can test for chain slack by rocking the crank back and forth a few degrees and you should be able to see the transfer of slack between the lower and upper loops.
Again, since slack will vary, do all measurements where it is least.