1973 Bonneville carb adjustment?

[ramwing7]

I am in the ending throes of the serious recommissioning of a 1973 Triumph T140V junkyard dog.  It's looking pretty good.

Now in trying to get it to run properly, it's not being terribly cooperative.

 Good news is that after almost 20 years of setting around and an electronic ignition, it started 2nd kick.
 Bad news is that it idles like it has a 3/4 race cam.  I've pulled alternating sparkplug wires, while it running, and it struggles and stops when the right plug is disconnected.  That points to something amiss on the left side.  It will accept throttle which leads me to the idle circuit, but the mixture screw seems to have no impact.

 I used the initial settings in the  workshop manual to get it started, but any change in those settings doesn't result in any smoothing of the idle.

 What should I do?

Thanks.

I did adjust the throttle cables so both slides move simultaneously.

[L.A.B.]

Sounds like a blocked pilot jet (pilot bush).
https://amalcarb.co.uk/rebuilding-mark-1-concentric-carburetter
"Pilot Circuit"

https://www.ntnoa.org/pdf/Bushmans%20Carb%20Tuning%20Secrets.pdf

If so then you need to make a 0.016" (drill bit/guitar string) tool to carefully clean it.

[R]

+1
As someone who once had a laid-up Commando that then idled like a dog, its perhaps worth mentioning
that those Amal idle passages can take a LOT of cleaning out. If moisture has gone into there, and caused
that white fluffy ? corrosion, it can take multiple cleanings to finally give a proper idle.
Have fun ...

[ramwing7]

Welp, you guys nailed it in one.

Blasted it liberally with carb cleaner and blew it out with the air compressor.

Got good flow, so I reassembled everything and it started 3rd kick and idled like it had always been doing it.

Now waiting on a temperature less than 104 degrees Fahrenheit to ride and fine tune.

Many thanks to all!!