| Also known as | E8015, OS52 |
| Diagram | Fig. 2 — CRANKCASE · ref 15 |
| Subsystem | engine bottom |
| Listed in parts books | 1968, 1970–1971 |
OIL SEAL BSA/TRI 1CYL HIGH GEAR
Oil seal for the high gear position in BSA/Triumph one-cylinder gearboxes, also known by its older number OS52.
This is an oil seal for BSA and Triumph one-cylinder machines, listed in our records as fitting the high gear position in the gearbox. The legacy number for this one is OS52, so if your parts book or an old baggie has that stamped on it, that's the same seal you're looking at.
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Seals like this keep gear oil where it belongs and keep it from working its way out along the shaft. On a single-cylinder gearbox, the high gear (mainshaft/top gear) area is one of the spots where a tired seal will let oil seep past over time.
We don't have much more detail on file for this one beyond what's above. If you're not sure whether it matches your particular gearbox casing or shaft, give us a call and we'll confirm before you order.
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