| Also known as | E4638 |
| Diagram | Fig. 27 — IGNITION COILS, HORN, RECTIFIER AND ZENER DIODE · ref 43 |
| Subsystem | electrical |
| Listed in parts books | 1963–1964, 1970, 1974 |
Screw bracket to frame
A frame-mounting bracket screw, PN 70-4638 (aka E4638), used in several electrical-component mounting locations on Triumph twins.
This is a small mounting screw, part number 70-4638, listed in the parts books as a screw for securing a bracket to the frame. It shows up across a handful of electrical-area figures, including the ignition coils, horn, rectifier and zener diode grouping, as well as the crankcase figure and the T100C ignition capacitor and headlamp listing. That spread tells you it's a general-purpose fastener the factory used in more than one spot rather than a single dedicated part.
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The older parts books list this same screw under the E4638 number, so if you're working from an early catalog or a bike with an older parts list, that's the number you'll see instead of 70-4638.
Because it turns up in electrical mounting points as well as crankcase-area listings, the safest approach is to match it up against the bracket you're actually replacing rather than assuming it's for one specific component. Bring the old screw or the bracket in question and we can confirm you've got the right one before you order.
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