This is the only one I know of.

https://www.cmsnl.com/en-ca/honda-cb77-super-hawk-1961-usa_model1001/seal-beam-unit_33120268670p/

However, you should shop around on Ebay and similar for a headlamp assembly that takes replaceable bulbs. They were installed in European bikes. This parts book ...

No. It's too wide.

The sound of the solenoid is a good start but I'm still wondering about your battery. If it fits the battery box the capacity should be fine if it is in good condition.

I would try disconnecting the big cables from the solenoid and connect them momentarily. This makes a direct connection from your ...

It just occurred to me that, of course, the problem could lie in any of the connections, large and small, at the solenoid and at the starter motor. If the solenoid is not the problem It's probably the starter motor. Let me know.

There's a service manual (along with some other interesting things) in ...

These relays (solenoids) are quite rebuildable. Often they just get gunked up with dust and corrosion so a cleaning will bring them back.

The two screws on the front of the relay are all that hold it together. The front piece will slide off although rust may make it difficult. The wire clamp (I ...

I've never seen a repair kit. It's good to know.

Something I forgot is that the main body of the clutch is hardened steel and they can crack. If that happens the clutch probably won't, well, clutch.

Use the kickstarter. ;-)

If the rollers and the crankshaft look undamaged, that is rust free and shiny, it may be that the clutch just needs to be cleaned. Any carb or brake cleaner in a spray can will work nicely. Follow it up with a light lubrication with silicone oil. That's what they recommend ...