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Main Area => General GS500 Discussion => Topic started by: utgunslinger13 on May 24, 2009, 05:53:40 PM

Title: Still messing with carbs, can someone educate me on Sync Set Screw?
Post by: utgunslinger13 on May 24, 2009, 05:53:40 PM
So I'm still working on getting my carbs dialied in from my other thread, but I was hoping someone with more Carb knowledge could educate me a little.  In my other thread I finally got an understanding on how floats and needles work but now I'm wondering how this set screw (or is it Sync Screw?) works.

My carbs have the brass caps drilled out so I'm now trying to figure out WHAT THIS DOES lol  I currently have it set at 2.5 turns out, but could someone explain to me what this controls and how 3 turns is different than 1 turn for example.  Just trying to make sense of these adjustments I'm messing with.

Thanks,

Nick
Title: Re: Still messing with carbs, can someone educate me on Sync Set Screw?
Post by: DoD#i on May 24, 2009, 08:14:38 PM
Somone will correct me if I'm wrong, but as far as I know those screws set the air/fuel mixture at idle - turning them out more increases the fuel, turning them in decreases the fuel, the air stays pretty much the same.

IIRC (haven't had to fsck with mine) they have little effect off idle (your mains, or mids and mains for the later 3-circuit carbs) set the mixtures there.
Title: Re: Still messing with carbs, can someone educate me on Sync Set Screw?
Post by: werase643 on May 25, 2009, 07:56:59 AM
it is the pilot screw
air comes thru the pilot air jet
fuel fron the pilot jet
and the mix then flows out the bypass ports and the pilot outlet
it is an air/fuel mix screw

Not a synch screw
Title: Re: Still messing with carbs, can someone educate me on Sync Set Screw?
Post by: The Buddha on May 25, 2009, 10:55:09 AM
Werase is right. Adding to that, the screw is a tapered obstruction in the fuel pathway.
Out puts less of it in the pathway, in puts more ... so out = rich.
Cool.
Buddha.