$5 Sync tool, trying to make but what is this "restriction" part of it??

[matchachicken]

Dear all at GSTwins,

I recently purchased a used 2002 GS500 that's been sitting for a couple years with 30k+ miles and want to do a valve adjustment and a carb synchronization on it before I take her out on the road. I looked thru the Wiki recently and saw a picture of a carb sync tool that can be home-made with aquarium tubes, but I am not sure what a certain part of it is referring to and the video links on the Wiki are old and no longer available to check...

What is this "restriction" referring to in the tubes going from the carb and the Aquarium T's? It's the line marked in RED

[Meukowi]

it's just some clamp that restricts the airflow(suction) thru the tube, without it it just would suck the water inside the carbs, if possible make it adjustable.

[matchachicken]

Aha! Thanks so much, that makes sense!

[herennow]

I have a couple of spécial hose clamps from a Chemistry class. it squeezer the hose with two parallel jaws. I use them on my rig with proper vacuma guages otherwise the suction causes the needle to bounce too much