TOPIC:

For what it's worth:
This past weekend I had the tank off for some general checking and maintenance. I decided to try a bit of an experiment because I've always wondered about the significance of the air induction ports found on the air filter side of the carbs. With the engine already warmed-up I blocked-off all 6 air (upper) ports to the idle circuit. Anticipating that the idle circuit would now be running rich with the lack of idle mixing air I turned IN the idle-needles to 1.5 turns. With this new setting the engine started and ran but required an additional increase in the main idle adjustment of about 1.5. This "cracked" the throttle plates enough to allow air for the idle-circuit but was still running so rich that even in an open doors shop, the Carbon Monoxide was literally burning my eyes. I then closed all 6 idle needles. The engine continued to idle but was still over-rich. Any opening of the idle-needles had no affect on the idle. "Blipping" the throttle produced black exhaust and the idle took several seconds to return. This indicated that idle fuel was being delivered in excess by the "transition" fuel jets in the venturi. I then removed the plugs from the (upper) idle air ports (the bottom ports supply mixing air to the emulsion-tube for the high speed needle) and as expected the engine was now "lean" and wouldn't idle. Opening up the idle screws to their normal 3.5 turns and backing off the additional 1.5 to 2 turns on the main idle adjustment put everything back to normal.
This in my mind clearly demonstrated the need to ensure that not only does the "wet" side of the idle-circuits be clean but of equal importance - so must the "dry" side.
If an issue develops where by a rich cylinder can not be leaned-out and all other parameters seem to be in order - Check the suspect idle-air induction port(s) for some form of blockage. As I discovered and wrote in about some time ago regarding a set of carbs I had purchased for rebuilding; Bugs seem to like these ports for a winter home! Keep in mind that the air induction ports are "jetted/metered" so it takes only a tiny piece of debris to block them.

Absolutely correct.

I remember a pic on this site of a carb inlet side with half of a fly larvae cocoon stuck in one of the 6 ports you mention. Truly amazing what animals or bugs will use for housing accommodations. I also recall another member showing a pic of mouse bedding inside of an airbox. Just go to show things we need to check on our bikes before firing them up after a long storage period. But this one that Scotch brings up is definitely something to be considered. Who would have thought you needed to check these ports.

LOL
That was possibly one I posted Kawboy.

I guess we could think of this as "de-porting" the pests! No affiliation or similarity with Trump's policy! All bugs have an equal opportunity in Canada!

McZed wrote: LOL
That was possibly one I posted Kawboy.

Yup, that's the one !!

scotch wrote: I guess we could think of this as "de-porting" the pests! No affiliation or similarity with Trump's policy! All bugs have an equal opportunity in Canada!

You may be on to something here Scotch. As Canadians we are very tolerant, especially with bugs.We all strain our beer throug.h our teeth and then spit out the bugs to give them a second chance. It's what we do.

Trump on the other hand doesn't read books, and gets all of his teachings through tv and social media. He needs to learn to stop squaking through his tweets. He's pissed at the meda sice all theyre doing is showing the world how stupid he is. If he read books I'd tell him to read " Zen and the art of Motorcycle Maintenance" , learn to chill and appreciate the smaller things in life. There is a saying which says " small things amuse small minds, but it takes a large mind to appreciate small things"