| Also known as | S550 |
| Diagram | Fig. 16 — FRAME · ref 18 |
| Subsystem | engine top |
| Listed in parts books | 1969–1974, 1976–1980, 1983, 1985 |
DOME NUT CHROME 3/8X24
Chrome dome nut, 3/8x24 thread, used at several points on the frame and engine assemblies where a finished cap nut is called for.
This is a chrome dome nut, 3/8x24 thread, the kind you'll find capping off exposed studs where a finished look matters and a plain nut would leave threads showing. It shows up across several parts-book figures including the gearbox inner cover and selectors, the frame, motor unit fitting and footrests, and the chaincase and chains area, so it's a general-purpose fastener used in more than one spot rather than a single dedicated application.
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Because it turns up in several different assemblies, the exact stud it's meant for on any given bike depends on which figure your parts book has it filed under. If you're chasing a specific dome nut for a specific job, check the figure your bike's book lists it against before ordering.
Catalog appearances run from the mid-1970s into 1980, consistent with later unit-construction Triumph twins. It's a plated fastener, so treat it as a cosmetic finish piece rather than a structural component to over-torque.
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