XS360 - low idle on choke

[cosworth]

So the bike runs great. Once it’s warmed up. And cold even...

But cold and on the choke, it doesn’t idle high and the throttle needs to be open. The air circuit on the choke is clean. The choke circuit is apparently clean (yes the holy trinity or mixture holes by the butterflies are clean). It’s been ridden all summer long. Carbs are synched, and in tune. Plugs are a wonderful colour. Diaphragms are in great shape. The hard rubber nubbin at the bottom of the choke plungers is is good shape.

I’m sorta stumped.

Only mods are repro headers and pipes. Paper filters have less than 1000kms on them. Idle mixture screws are 7 half turns out, or 3 1/2 turns. No pops on decel. Slight pops at 3 turns out.

Any ideas?

 

[cosworth]

Found it.

Previous owner had broken off a wire inside the choke emulsion tube. I guess cleaning it. 150psi air pressure and a sleeved adapter for a tight fit and I got it to poke out a bit. Thankfully when I yanked on it, sliding out was the result. Not breaking off again. It was about 4mm long.

These carbs have given me headaches...