| Also known as | OS39 |
| Diagram | Fig. 9 — INNER TIMING COVER, GEARCHANGE MECHANISM · ref 16 |
| Subsystem | engine bottom |
| Listed in parts books | 1970–1973 |
OIL SEAL C15 B40 A65 POINTS SHAFT (1.00 x .625 x.187) Same as 70-4568
Oil seal for the points shaft on BSA C15, B40, and A65 models, sized 1.00 x .625 x .187.
This is an oil seal for the points shaft, sized 1.00 x .625 x .187. The catalog description ties it to the C15, B40, and A65 - all BSA models, not Triumph, despite what the manufacturer tag on this listing says. It's also cross-referenced to 70-4568, so if your parts book lists that number instead, this is the same physical seal.
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A points shaft seal like this keeps oil from creeping past the shaft where the contact breaker mechanism penetrates the timing cover or crankcase, so the points stay dry and the engine doesn't seep oil out of that opening.
The legacy alias for this part is OS39. If you're working from an older BSA parts book and see OS39 or 70-4568 listed, they all point to the same seal listed here as 76-0291.
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