| Diagram | Fig. 11 — CLUTCH — PRIMARY COVER (Plate 9) · ref 15 |
| Subsystem | primary |
| Listed in parts books | 1972 |
BSA Cap nut — adjuster screw (7/16" B.S.F.)
Cap nut for the primary chain adjuster screw, 7/16 in. BSF thread, part 57-4424.
This is the cap nut that covers the primary chain adjuster screw, part number 57-4424. It's a small piece but it does a real job: it seals off the adjuster screw threads so grease and road grit stay out and the adjustment doesn't creep on you once it's set.
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The catalog lists it under the CLUTCH — PRIMARY COVER figure, which puts it right where the primary chaincase meets the adjuster mechanism. It's threaded 7/16 in. BSF to match the adjuster screw it caps off.
Our record only shows this one appearance, tied to a single year in the catalog, so if you're trying to match it to a specific machine, give us a call and we'll confirm before you order.
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