I have a singlespeed drivetrain set up as such:

1/8" chainring
1/8" chain
1 3/32" bmx freewheel

And I'm getting a intermittent clicking sound only when pedaling. Chainring bolts are tight, crank fastening bolts are tight, bottom bracket is tight, chainline is straight, no especially loose spokes found. It comes and goes as I pedal. Sometimes coasting for a moment stops it.

Ideas?

freewheel's probably busted. maybe a broken or chipped pawl?

Take the pedals off, grease up the threads and screw em back in...tight...very tight. The noise will be gone.

ah yeah. pedals are also extremely likely. check anything with bearings in the drivetrain.

I doubt it's the freewheel-- it's got a couple hundred miles on it at most, and it's not some weird offbrand ( but an ACS claws).

Time to check the pedals for play...

yeah if it's acs you should be fine. you said 'bmx' i assumed you meant a lowgrade shimano or such.

if all else is well, make sure it isn't the hard tip on your shoelace hitting your chainstay. i drove myself crazy searching for the cause of a click that ended up being just that.

+1. Same thing happened to me.

could be a bent or stiff link in your chain.

+1 I do this about once a month.