BSA C15/B40 19T Gearbox Sprocket – Classic Bike Shop OEM 40-3123 Replacement

Brand new, never used.

This is a 19-tooth gearbox sprocket made for BSA C15 and B40 models, put out by the Classic Bike Shop.

It’s their part number 300119, and it matches up with OEM number 40-3123.

So if you’re rebuilding or fixing up your classic BSA’s transmission, this is the one you need.

No ISBN included, but it’s a solid, direct replacement part.

Just make sure your bike’s setup calls for a 19T sprocket.

Sturdy, reliable, and ready to bolt on.