| Diagram | Fig. 1 — CYLINDER AND CRANKSHAFT · ref 22 |
| Subsystem | engine bottom |
| Listed in parts books | 1969–1970, 1973 |
BSA Nut, cylinder stud (5/16" British Standard Cycle)
A 5/16 inch BSC nut for a cylinder stud, used to secure the cylinder to the crankcase.
This is a 5/16 inch BSC (British Standard Cycle) nut used on a cylinder stud, part of the hardware that clamps the cylinder down to the crankcase. It shows up in the parts book under the CYLINDER AND CRANKSHAFT figure, which is where you'd expect to find cylinder base fasteners.
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The manufacturer code on this one reads BSA in our records, but the description just calls out a standard 5/16 BSC nut on a cylinder stud - the kind of fastener that turns up across a lot of British bikes from this era, not something we can tie to one specific make or model from what's in front of us. If you're rebuilding a bottom end and need to replace stud nuts, this is the thread standard and size to match.
Our catalog listing spans 1969 to 1970 across a few appearances, but that's just what we've got on file for repeat listings - it doesn't tell us which exact model or engine it was fitted to. Bring in the stud or the old nut if you've got it and we'll match it up before you order.
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.
Sorry if we got something wrong here. If you think this information isn't correct, .