Can't get Carbs to Sync

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Jerry Kaiser

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I have rebuilt the Carbs on my 80 GL1100. Now I am trying to sync the carbs. The #3 carb has 40-50 inches of vacuum
and I can not sync the other carbs to that. The best I can do is sync #1,#2 and #4 at about 12 inches of vacuum. I have checked for a vacuum leak at #3 but have found nothing. The right side seems to be running lean by the look of the pipes gray color the left side is black. I feel I will need to remove the carbs and was hoping for some advice as to what to look for when I do.
Any help would be deeply appreciated.
 

chilidawg

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Your #3 carb gauge is reading incorrectly, greater than 30 inches of Hg vacuum does not exist. the 12 or thereabouts on the other carbs is a much more likely reading.

I would swap the gauge leads around and see if the problem follows that gauge, I'll bet there will be a little calibration required somewhere.
 

mcgovern61

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Did you perform a bench sync first? That is where you have the carbs off and set hem all to the same butterfly level prior to installing. Look inside the carb with the butterfly fully closed and you will see a tiny hole in the side. Set each butterfly to be at exactly the same level with the butterfly's just at the hole and then install and sync on the bike.
 

Jerry Kaiser

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Yes I did bench sync them when I had them off. Not saying my gauges are totally accurate but I did switch gauges and still get the same reading. Thanks for the ideas because I have just about ran out
 

pidjones

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Depends on the gauge calibration. Inches mercury or water? Also, some are psi, mm of mercury, Torr, Barr or mBarr. Have you checked compression and timing? Both must be right before balancing.
 

Jerry Kaiser

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Thanks for everybody's help but I finally got it. I had backed off the idle speed screw to much and had the #3 carb way out of wack. It took about 10 minutes to sync them. One of the guys on the other forum said that I may have the idle screw to far out and that is exactly what the problem was
 
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