What is this?
Seasoned HDF Member
Joined: Dec 2010
Posts: 6,846
Likes: 1,386
From: Florida
It was an aftermarket accessory by a separate company that was made to deliver more power. Kind of like torque cones do for exhaust. I can't think of the name of the company but it is supposed to make the air like a tornado for better mixture and more air I guess
Tourer
Joined: Apr 2012
Posts: 345
Likes: 3
From: Manhattan
Last edited by Esuomm1; Jan 17, 2014 at 11:14 PM.
Seasoned HDF Member
Joined: Dec 2010
Posts: 6,846
Likes: 1,386
From: Florida
Yost! That is what I was trying to think of. I just turned thirty and my memory doesn't work that well. Haha. If I am not mistaken doesn't the gas shoot out of the middle of the circle
Outstanding HDF Member
Joined: Jun 2007
Posts: 3,306
Likes: 5
From: Bellville, Tx
The Yost is a small venturi which increases the flow over the main jet and act just like the larger venturi of the carb intake. The idea is that the air fuel mixture expands as it exits the tube giving better dispersion into the manifold. I've never used one so can't comment on any improvement.
Road Master
Joined: Apr 2011
Posts: 908
Likes: 96
From: Red Deer, AB
Looks like a Power Tube. Yost made them and a couple others. Haven't seen one in about 25 years and that was on a snowmobile. Some guys swore by them.
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Road Captain
Joined: Aug 2012
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From: New Albany, Ms.
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Road Warrior
Joined: Aug 2007
Posts: 1,557
Likes: 66
From: Oakdale Ca.
its a dacincci "gun site" or "bulls eye" takes the flat spot ot of S&S carbs. I just installed one and it was night and day. you can actually see the difference turns the fuel squirt into a fuel mist..... best 40 bucks I have spent in a while.