| Diagram | Fig. 8 — TIMING COVER AND CONTACT BREAKER · ref 8 |
| Subsystem | engine bottom |
| Listed in parts books | 1968, 1970–1971, 1974 |
Auto Advance Unit (99-1771)
Auto advance unit for the timing-side ignition assembly, works with the contact breaker to advance timing as revs rise.
This is an auto advance unit, the mechanism that lives behind the timing cover and works with the contact breaker to move ignition timing as engine speed climbs. It shows up in the timing cover and contact breaker section of the parts books, which tells you it mounts on the timing side of the engine, ahead of the points.
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The catalog also lists this part under 99-1771, so if you're working from an older parts book or a supplier list and see that number, it's the same physical unit as 54419340.
The catalog record spans a run of years across multiple listings, but we don't have anything more specific tying it to a particular model here. Bring in your old unit or check your parts book number against this one before you order, since advance units aren't all interchangeable across the different points and cam arrangements Triumph used over the years.
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