| Also known as | 68-662, I106 |
| Diagram | Fig. 3 — CYLINDER BARREL, EXHAUST PIPES, VALVES · ref 8 |
| Subsystem | engine top |
| Listed in parts books | 1969–1970 |
EX VALVE BSA 250/A50
Exhaust valve for BSA 250 and A50 models, listed under 68-0662 (formerly I106, superseded by 70-7777).
This is an exhaust valve, and the catalog description ties it to BSA 250 and A50 machines, not Triumph despite what the manufacturer tag on this listing says. The part lived under the older I106 designation before the factory renumbered it, and it has since been superseded again to 70-7777, so if you're cross-checking an old parts book against a newer one, those are the numbers to look for.
Read more
An exhaust valve sits in the cylinder head and opens to let spent combustion gases out of the engine on the exhaust stroke, then seats back down to seal the cylinder for the next cycle. It's a wear item that takes direct heat and combustion pressure every time the engine runs, so it's the kind of part that gets replaced as a matter of course during a head rebuild or valve job.
We don't have much more detail on file for this one beyond the BSA 250/A50 application noted in the description. If you're sourcing this for a specific bike, call the shop and we'll confirm fitment before you order.
Sorry if we got something wrong here. If you think this information isn't correct, .