| Diagram | Fig. 3 — CRANKSHAFT · ref 25 |
| Subsystem | engine bottom |
| Listed in parts books | 1969–1972 |
BIG END SHELLS .030 BSA
Big end bearing shell set, .030 undersize, for a BSA engine bottom end.
This one's a bit of an odd duck to have under a Triumph part number. The catalog entry plainly names it as a big end shell set for a BSA engine, ground .030 undersize for a reground crank. Big end shells are the bearing inserts that sit between the connecting rod and the crankpin, and running an oversize or undersize set like this is standard practice once the journal has been machined down from wear or damage.
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We don't have much more in our records to go on beyond that description, so we can't speak to which BSA engine family this was cataloged against. If you're rebuilding a BSA bottom end and need the .030 undersize shells, give us a call and we'll confirm what you've got before it ships.
Given the crossed wires between the Triumph part number and the BSA description, treat this as a part worth double-checking against your crank's actual measured journal size before you order.
Sorry if we got something wrong here. If you think this information isn't correct, .