| Diagram | Fig. 3 — CYLINDER BARREL — EXHAUST PIPES — VALVES · ref 35 |
| Subsystem | engine top |
| Listed in parts books | 1971–1972 |
VALVE GUIDE BSA 500/650
Manganese bronze valve guide for BSA 500/650 twin cylinder heads, usable as inlet or exhaust.
This is a valve guide for BSA's 500 and 650 twins, not a Triumph part despite how it's filed in our system. It's made from manganese bronze and can be worked with standard reaming and honing tools, so an engine builder doesn't need special equipment to finish it to size. The catalog notes it's cut to a .002 in. fit.
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The old parts-book alias for this one shows up as OCT-35, so if you're working from an older reference and see that number, it's the same guide. Grounding from other catalogs points to fitment on the last generation of BSA A65/A70 cylinder heads, and it's usable in either the inlet or exhaust position.
Give us a call if you want to confirm this is right for the head you're working on before you order - valve guide fitment can vary enough across BSA head generations that it's worth double-checking.
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