| Also known as | E4771, WW27762 |
| Diagram | Fig. 4 — CYLINDER BLOCK AND HEAD, 6T AND TR6 · ref 22 |
| Subsystem | engine top |
| Listed in parts books | 1964–1965, 1967–1968, 1970–1971 |
Bolt (3 in. U.H.)
Cylinder head bolt (3 in. U.H.) used on Triumph 650 twin cylinder block and head assemblies.
This is a cylinder head bolt, one of the fasteners that clamps the head down onto the barrels on Triumph twins with the 9-stud head arrangement. The catalog calls it out as a 3 in. U.H. bolt, and it shows up specifically in the cylinder block and head figures for the 6T, TR6, TR6R, TR6C, T120, and T120R across catalog years 1964 through 1971.
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If your parts book has this listed under the older E4771 or WW27762 numbering, that is the same physical bolt under a legacy reference. It is a small part but an important one for keeping even clamping pressure on the head, so check the condition of the threads and the bolt length against what came out of your engine before ordering.
Given how many head bolts a single top end uses, it is worth checking the rest of the set while you have the head off rather than replacing just the one.
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