I have been trying to track down an irritating but elusive ticking noise which only appears when I am giving my singlespeed bike some stick. It usually only happens when I am riding uphill. Lower pedalling forces don't cause it.
It isn't the chain - the old one snapped and the noise is still happening with the new chain.
It isn't the pedals - I swapped in another pair and the noise remained.
It isn't the seatpost/saddle - the bike is still noisy when I pedal standing up.
I am (almost) certain that the tick isn't coming from the front of the bike so it isn't the bars, stem, fork, front wheel, headset or brake hoods.
I wondered about the bottom bracket. I checked it and thought I could feel a little play. I had found a really nice newish Chorus BB in my spare parts box so I swapped that in and... it feels smoother than the old one but the noise is still there.
The freehub is next to be investigated. I found another one in the spares box so that can be substituted for the current one. The new BB is slightly shorter than the old one so my previously perfectly chainline has been lost. It isn't bad now, but I need to move the sprocket by 1 spacer to get it perfect. I can check/replace the freehub while I am at it.
PS I forgot... I went to tighten the chainring bolts and 2 of the 5 are rounded off internally so the hex key slips. I can't make sure that they are tight enough. I'll have to get them out somehow and replace them with new ones. I'll look for a screwdriver with a blade the right size that I can hammer into the holes to get a grip.