My chain keeps falling off – is this a simple fix?

[yamahafx1]

Why does my chain keep falling off? Im no stranger to bike maintenance and have upgraded components on my 2002 Trek 5200 frame and 1999 Trek 5500, but this issue has me stumped. Ive checked for worn-out components, properly adjusted the derailleur, and ensured the chain length is correct, but the chain still falls off. Is there something simple Im overlooking, or is this a more complex problem? Any insights or suggestions would be greatly appreciated.

 

[EX2]

Sounds like you've covered all the basics! Have you tried tweaking the high and low limit screws on your derailleur? It's a simple fix that often gets overlooked. Keep fighting the good fight, and remember, even the pros encounter stubborn chains from time to time