| Also known as | 40-209 |
| Diagram | Fig. 1 — CYLINDER HEAD, EXHAUST PIPE · ref 6 |
| Subsystem | engine top |
| Listed in parts books | 1969–1970 |
BSA Nut, rocker box (1/4" British Standard Cycle)
A 1/4 inch British Standard Cycle nut used in the cylinder head/rocker box area.
This is a 1/4 inch British Standard Cycle nut used up in the rocker box area of the cylinder head. It shows up in the catalog under the cylinder head, exhaust pipe, and cylinder and crankshaft figures, which tells you it's a small fastener doing its job somewhere around the top of the motor rather than anything structural on its own.
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The BSC thread standard is a fine-thread spec, and if you're rebuilding a top end and pulling old fasteners you want to make sure you're matching this thread rather than grabbing a generic hardware-store nut that happens to look close. Mixing thread standards on old British iron is how you strip something you didn't mean to.
Our catalog record has this appearing across 1969 to 1970 listings, so it's worth checking your parts book figure against what you're working on before you order, since we don't have more beyond the figure titles and the thread call-out itself.
We've never carried this one. Tell us what you're after and we'll go looking — you'll get a price and photos before you commit to anything.
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