What part of the Hatachi Carbs feed YICS.

I was wondering what circuit in the carb feeds the dumb YICS? Is there a way to clean the passages out?

 

The "dumb" YICS passage is not fed by the carbs.
It's a passage that runs along the back of the head, right under the intakes sealed by a bolt at both ends.
You can clean the passage out with a thin rod and a rag soaked with carb cleaner.
There are also 4 small "ports" along the top of the passage that you can use a 90° pick or firm wire to poke through them.

 

If I'm not mistaken, the YICS is part of the air intake system and is supposed to cause a swirling of the intake gases resulting in better combustion. I don't think there is any part of the carbs that is dedicated to the YICS. I cleaned mine with a gun cleaning brush soaked with carb cleaner and then pulled a strip of cotton cloth through it. Some folks say that you can take a piece of small diameter wire, sharpen and bend end to make a simple probe to clean the 4 small intake channels. I didn't do that because I was afraid that I would push crud into the channels rather than clean them.

 

why do you call the yics dumb?

 

Was just quoting what the OP posted.
I don't think it's dumb, he does.
Of course, just because he can't get his bike running right...
He thinks Yamaha engineers were dumb too.
Go figure!

 

YICS is not directly related to the carbs, or which carbs are fitted. YICS is a series of passages in the intake tracts (connected by a passageway in the cylinder bank) that feed the combustion chambers.

There are Mikuni-equipped YICS motors too.

YICS:

 

altlandf (not midnightmoose) calls everything on these yamahas by one derogatory or another, just check his post history. Carbs are his mortal enemy.

Best thing I found for cleaning the YICS passage was actually a rifle cleaning kit. Most excellent.