| Also known as | 99-1263 |
| Diagram | Fig. 10 — TIMING COVER AND CONTACT BREAKER · ref 18 |
| Subsystem | engine bottom |
| Listed in parts books | 1974, 1976–1978 |
AUTO ADVANCE UNIT
Lucas automatic ignition advance unit that mounts behind the timing cover with the contact breaker points.
This is the automatic advance unit that lives behind the timing cover, in with the contact breaker points. It's the mechanical piece that lets ignition timing come forward as the engine picks up revs, so you get a milder spark advance at idle and more at speed without doing anything yourself.
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In the parts books this one also shows up under the older number 99-1263, which is the legacy form of the same physical unit. Our catalog record only ties this listing to a single year appearance, so if you're chasing exact fitment for your machine, best to check the points and timing cover setup you've currently got before ordering.
It's a Lucas unit, consistent with the electrical/ignition side of the bike. If the points and advance mechanism in your timing chest look tired or the timing has started drifting, this is the part that usually needs attention.
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