Serangoon, 11 km. Click, click, click. With every pedal stroke, the click drives me further round the bend. I grease the seat post. That usually works - but not this time. Then I remove the seat from the seatpost and grease all contact points. I bounce on the seat, no click. So it must be some rotating part. Not the pedal nor crank, since the click continues when I coast and rock from side to side. The wheels then? I squeeze where the spokes cross each other. There are no clicks when I place the bicycle upside down and spin the wheels. The click stops when I cycle uphill. I hold the handlebars down with my bodyweight and turn. Click, click, click.
I cycle to see bikeshop man. I wait about two hours, as he works on an "are they still in production?" Made in India Hercules bicycle. Then on a Lynskey. Finally, it’s my turn. Bikeshop man takes apart my headset, soaks part of it petrol and says “lots of sand”. Not to mention water that flows out. “Ride in heavy rain?” he asks. I pick up a rag and wipe the head tube. He puts everything back but before the job is done, another cyclist shows up. It’s now past 10 pm. Bikeshop man starts giving advice to him and I finish my own job before paying up and cycling off.
Troubleshooting? Use your head (and ears). Isolate and eliminate, what’s left is the problem. This method (use head and ears) works elsewhere in life too.