| Diagram | Fig. 26 — CONTACT BREAKER AND IGNITION COIL · ref 1 |
| Subsystem | engine bottom |
| Listed in parts books | 1963–1964 |
CONTACT BREAKER, type 4CA
Lucas 4CA contact breaker assembly for the ignition points system, from the contact breaker and coil figure in the parts book.
This is a Lucas 4CA contact breaker assembly, the points unit that lives under the timing cover and makes and breaks the ignition circuit as the engine turns over. The 4CA designation refers to Lucas's own contact breaker type, and it shows up in the parts book under the figure for the contact breaker and ignition coil, so it works alongside the coil to fire the spark at the right moment.
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Our catalog record for this one spans appearances in 1963 and 1964, but we don't have anything more specific tying it to a particular model in our records. If you're matching this up to a bike, check the physical unit and points gap against what's already on there, or give us a call and we'll help confirm before you order.
These units wear as a normal part of service - points pit and burn over time - so if yours is getting hard to set or hold a gap, this is the kind of part that gets swapped out during a tune-up.
We've never carried this one. Tell us what you're after and we'll go looking — you'll get a price and photos before you commit to anything.
Sorry if we got something wrong here. If you think this information isn't correct, .

