Hi Dj - it's a Yamaha SR 125 Custom 1996 but I don't normally broadcast it and I wear a full face helmet.
Cheers
My experience with metric machinery is somewhat limited, unless you ride a Honda (pushrod) 90 cc with a cast iron top end, a Honda 305 or a Suzuki X6 Hustler.
I can’t speak directly to the inner workings of your Yamaha but I believe that for the most part the metric motorcycle manufactures run a chain driven direct drive starter similar to the VRod…and the 305 Honda now that I think about it. The Harley air cooled machines run a starter with a retractable starter drive. The retractable starter drive mechanism is much more complex than the direct drive design. The complex mechanism requires a few more steps to diagnose.
Assuming that the starter motor on your Yamaha is mounted externally; I feel that diagnosing your starting issue shouldn’t be a real big deal; easier for me to say than for you since my machine starts just fine.

The first thing that I would do is to eliminate the starter relay. The relay on the Yamaha is much more robust than the one on your H-D; the H-D relay only powers the solenoid, the Yamaha relay handles the power necessary to crank the engine. Select an appropriate jumper cable, something large enough to handle the current necessary to crank the engine. Attach one end of the jumper to the battery positive post and the other end to the power terminal on the starter motor; if there is an issue with the starter relay or related wiring, the engine will begin to crank as soon as the jumper is attached.
If the starter does not operate after bypassing the starter relay, it is a safe bet that the issue is in the starter motor itself. The starter drive mechanism functions normally when the machine is dropped in gear and moved backwards, engaging the starter clutch and rotating the starter armature.
If the starter relay has been eliminated, go ahead and try whacking the starter motor with something that will not damage the finish of the starter; large hard plastic screwdriver handle, etc. The ignition and kill switch should be on; depress the starter button and strike the starter with an appropriate persuader in an assertive manner. If the starter cranks the engine, the starter motor requires service. The starter is most likely not worn out but simply has a corrosion issue or maybe a sticky brush or other problem creating high resistance in the circuit.
Good luck Smiler,
djkak