After having slow running problems I guessed that lack of use over the winter months had gummed up one of the pilot jets. The Haynes manual only shows them stripping the Thundercat carbs but it's easy enough to suss out which is the pilot jet. My question is though, what is the brass jet next to the main jet with no hole through it and what's it's purpose? Running like a Swiss watch again now though.
Are these both the long screw out jets with the small offset holes in them you're talking about or the small stubby one that's about 10mm long?
The small stubby one similar in appearance to the main jet, minus the hole.
Yeh it has no hole. No idea what it's supposed to do!! Although I've heard it's something to do with vacuum management.
I spent about 15 minutes trying to unblock the hole in the one doesn't have a hole in it.
I know I should've gone to Spec Savers.
In any event I reckon it's just a blanking plug, put in a hole for a jet that was needed.