| Also known as | H400 |
| Diagram | Fig. 6 — CYLINDER BLOCK AND HEAD · ref 36 |
| Subsystem | engine top |
| Listed in parts books | 1963–1970, 1974 |
DOME NUT,CAD 5/16X26 - For Chrome use 97-1531
Cadmium-plated 5/16x26 dome nut for the cylinder head area on smaller unit Triumph twins; chrome version is 97-1531.
This is the dome (acorn-style) nut used on the cylinder head area of the smaller unit-construction Triumph twins, per the catalog figures for CYLINDER BLOCK AND HEAD across the 350 and 500 range - 3TA, T90, T100S, T100C, and T100R among the listings. It's a 5/16 x 26 thread, cadmium finish, and Ed's counter notes point to it living on the rocker oil feed line fitting at the head, based on other catalog listings for this same number.
Read more
The legacy book number for this one is H400, so if you're working from an older parts book and turning pages looking for a match, that's the one to cross off against 97-0400 - same physical nut.
If you're doing a chrome rebuild rather than a cadmium respray, there's a chrome equivalent under 97-1531 - same nut, different finish, so don't mix them up when you're ordering for a show-finish job versus a driver.
Sorry if we got something wrong here. If you think this information isn't correct, .