Fuel drip when choke is on?

[High Desert]

I have a fuel leak sometimes.  It is under the tank.  It only happens when it's running.  Now I think it only happens when the choke is on.  Is there a reason that fuel would drip around the fuel line or rail when the choke is (way) on?  (I cannot see exactly where the drip is occurring.)

[sandy]

The running engine is because the petcock requires a vacuum to flow. So the leak is after the petcock. I have not heard of a leak with a full choke.

[WintrSol]

I've never heard of it, but it looks possible. The 'choke', or enrichment valves open a bypass from the pilot/idle mixture jets into the carb outlet, so is directly exposed to fuel, and slides in and out when used. All it would take is a failing seal on the moving part.

[Pluggy]

With the tank on, it is hard to find the source of a fuel leak.  Gotta take the tank off.  Mini tanks like this one allow us to see where the leak originates.  We can safely run the engine using this if necessary.

https://www.amazon.com/Royal-Vintage-Spare-Auxiliary-Servicing/dp/B018FVLFZY/ref=sr_1_10?crid=19XZ3FD0O8U78&dib=eyJ2IjoiMSJ9.bPatZmRY0_vEOpL7fV9_MlQnNvvcxx0VnWpnHGWq9Z0xGYPuXPeH7xh4RZ3hrcSzVyxUfYFWycg09YvlPglWMW5CWaXk5dGX_2BE5bLxofBwHGZThxmG2Ngv2ykVQ1bNzpqzkKdbPsTDBng1X7dLjAdx2d99tBydlsfqXqYso1Uhe3YISIM_yjIAg32NEqt6mpwWUy3CHRVEag7d7ED2PaRnpxf2Sx0fD-Y-JlKwZOiZIwQG_UsqOr7Gmum0ncrwsvS6vlpmRDMqKULoz1yNyMEv7ZjBDxqGmsMk0__z9Pk.O0mG1SQvPpbQOcVsld4ScZdbb_5zBBOoQK5IXhnbjmA&dib_tag=se&keywords=motorcycle+test+gas+tank&qid=1750728824&sprefix=motorcycle+test+gas+tank%2Caps%2C196&sr=8-10

(Don't try riding with this)