| Diagram | Fig. 7 — TIMING COVER AND CONTACT BREAKER · ref 27 |
| Subsystem | engine bottom |
| Listed in parts books | 1971–1974 |
AUTO ADVANCE UNIT (99-1015)
Mechanical auto advance unit for the ignition, mounted behind the timing cover alongside the contact breaker points.
This is the automatic advance unit that lives behind the timing cover, right alongside the contact breaker points. It's the mechanical unit that adjusts ignition timing as engine speed climbs, using spring-loaded weights to advance the spark as the motor revs up. Also carried under the earlier number 99-1015, which is the same physical part under its older book listing.
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On these machines the auto advance sits inline with the points and cam, so when it wears out or the springs go soft the ignition timing gets sloppy and the bike runs poorly at certain rev ranges. The catalog places it squarely in the timing cover and contact breaker area, appearing across catalog listings from the early-to-mid '70s.
If you're chasing an ignition timing gremlin, this is one of the usual suspects to check before you start swapping coils or points. Call the shop if you need help confirming which auto advance unit matches your points setup before ordering.
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