| Also known as | 28T, E8773 |
| Diagram | Fig. 4 — CYLINDER HEAD AND ROCKER BOXES · ref 13 |
| Subsystem | engine top |
| Listed in parts books | 1969–1974 |
ROCKER BOX GASKET 3CYL
Rocker box gasket for the Triumph/BSA three-cylinder engine, seals the rocker box to head joint.
This is the rocker box gasket for the three-cylinder Triumph/BSA engine, listed in the catalog as 70-8773. It seats between the rocker box and the cylinder head, sealing the top-end oil that lubricates the rocker gear so it stays where it belongs instead of weeping out around the cover joint.
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The older reference for this part shows up under the number 28T, so if your parts book or an old box in the shed carries that stamp, it is the same physical gasket. The factory record shows this PN was later superseded by 70-8773E, so if you are matching up numbers from a more recent catalog that is where it lands.
We don't have model-year specifics tied to this listing beyond it being for the triple-cylinder engine. Gaskets like this are cheap insurance against a slow oil seep at the rocker box joint, so it is worth having on hand any time you have that cover off. Call the shop and we'll confirm fitment details before you order if you're not sure which triple you've got.
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