| Also known as | I115, T2683 |
| Diagram | Fig. 3 — GEAR CLUSTER AND TIMING COVERS · ref 76 |
| Subsystem | engine bottom |
| Listed in parts books | 1968, 1970 |
PINION-KICKSTART RATCHET
Kickstart ratchet pinion gear for Triumph and BSA unit singles, engages the mainshaft when you kick the engine over.
57-2683 is the kickstart ratchet pinion gear for the Triumph and BSA unit singles line. This is the toothed gear that engages when you swing the kickstart lever down, transferring that motion into the mainshaft to turn the engine over for starting. Once the engine fires, the ratchet mechanism lets the gear disengage so it's not spinning with the rest of the works.
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The part carries an older T2683 designation in some parts books, which is the same physical gear under the earlier prefix numbering. It shows up across the unit single lineup rather than being tied to one specific model, so if you're chasing this down from a parts book listing for a B25, B40, B44, or similar unit single, you're likely looking at the same gear.
We don't have a lot of extra detail on file for this one beyond what the parts books show, so if you've got questions about bore size or which gear variation your bike needs, give us a call before you order and we'll sort it out with you.
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