The thick ones go on top where the fuel injector meets the rail. My best guess is 3mm thick by 1.5cm outer circumference. |
The skinny ones go on the bottom where the fuel injector slides into the intake manifold. |
My best guess there is 2mm wide by 1.4mm outer circumference. |
The All O-Rings site also has a good description of the materials you want to get your o-rings in. Nitrile and Viton are what I went with in the pointless Amazon order, but those are the materials you want in a fuel heavy application like this.
That's the configurator (right) - pretty straightforward, but it sounds like they manufacture each order, which probably won't make this a viable solution for someone just trying to keep their old Triumph on the road.
If only there was some kind of network of retailers who supported Triumph motorcycles who could order this parts to help their customers keep their older Triumphs rolling... some kind of 'dealer' network who understand how parts work and how to order this sort of thing in large enough quantities to make a profit while offering customers what they need.
RESOURCES
How hot motorcycle engines runs: https://blog.amsoil.com/extreme-heat-is-hard-on-your-motorcycle/Buna (Nitrile or NBR) o-rings: https://sealingdevices.com/o-rings/buna-n-o-rings/
Viton vs. Nitrile o-rings: https://www.nes-ips.com/viton-vs-nitrile-o-rings/
All O-Rings https://www.allorings.com/
They have sizing tools! https://www.allorings.com/o-ring-kits-and-accessories/o-ring-sizing-tools
I'd prefer to use All O-Rings for the parts, but they might be a B2B type of thing, and I'm not a B.
Amazon's kits: