How to synchronize your carburetors


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deaconales
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Re: How to synchronize your carburetors

Post by deaconales » Sat Jul 05, 2014 9:37 am



dhg- thank you for the insight!



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spookytooth
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Poor-man's Carb sync...

Post by spookytooth » Sun Aug 17, 2014 9:23 pm





Comprised of these parts...
http://www.amazon.com/gp/product/B00A8X ... ingdocs-20
http://www.amazon.com/gp/product/B00025 ... ingdocs-20
http://www.amazon.com/gp/product/B00IJ7 ... ingdocs-20
http://www.amazon.com/gp/product/B0094F ... ingdocs-20
http://www.ebay.com/itm/200985019155?_t ... EBIDX%3AIT

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WingAdmin
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Re: Poor-man's Carb sync...

Post by WingAdmin » Tue Aug 19, 2014 12:18 pm

That's great! The valve adapter is fantastic! I'm going to move this as part of the carb sync How To.

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mrtwowheel
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Re: How to synchronize your carburetors

Post by mrtwowheel » Thu Sep 11, 2014 10:55 pm

For anyone using the Harbor Freight or similar gauges in the two or four gauge method that would want to synchronize one gauge to another. The bezel and glass pop off of these gauges, between 5 and 6 oclock on the dials there is a brass screw. This screw can be turned to adjust the needle. Using the same carburetor and vacuum port, each gauge can be compared to another gauge and adjusted with the brass screw. Better yet, each complete unit of hose, valve, restrictors and gauge can be compared and adjusted to read the same.

Scott

rich1966
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Re: How to synchronize your carburetors

Post by rich1966 » Tue May 26, 2015 9:47 pm

having problems synchronizing my 1982 goldwing I got the right side synchronizedthen the left side synchronize but cant in get them to match the right side was 20 left side 10 and I can get them to go up or down to meet other am I doing something wrong need help thanks rich

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FlashBack
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Re: How to synchronize your carburetors

Post by FlashBack » Wed May 27, 2015 9:31 am

One thing i learned this weekend is to not only use the gauges for synchronizing carbs, but use the human element as well and listen to them and make slight adjustments. I was always getting a mediocre at best sync by gauges only. I decided to use my ears and was able to really dial in the sync.
Just my two cents worth.

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Oldbear
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Re: How to synchronize your carburetors

Post by Oldbear » Sun May 31, 2015 12:49 pm

Syncing your carbs can make a huge difference in performance, fuel economy and smoother running engine. I've been syncing my carbs and those of my friends for years. The old Motion Pro finally sucked or leaked all the mercury out. I built a version that I stole the idea for from here. It's the poor man version to test the setup and get my carbs done. I'll make it all pretty on a rain day... I'm not wasting my short riding days building a fancy case.
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warhead_71
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Re: How to synchronize your carburetors

Post by warhead_71 » Tue Jun 14, 2016 9:33 am

Just FYI, a lot of RC boats use the same M5 brass nipples to plumb their water cooled engines. I have found them online for as little as 25-cents apiece, plus shipping. They don't include O-rings but I think a smear of RTV should work just fine.
78 GL1000 Goldwing "Superhawk" - album
previous bikes: 84 V65 Magna | 83 V45 Magna | 81 CB650 | 68 CL350 | 69 CB350 | 76 CB360T | 73, 74, 76 CB750K

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tylers883
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Re: How to synchronize your carburetors

Post by tylers883 » Tue Jul 26, 2016 9:05 pm

great instructional!

WingAdmin, I have a question for you, please respond when you have time...

I'd like to solve the error problem by substituting the vacuum meters with manometers( ie vertical displacement of water in a tube). All manometers, regardless of tube diameter and volume, will inherently report the same vacuum or pressure. There is a physics 101 explanation to this that I care not to learn about, so please dont ask me to repeat it - LOL.

Anyway, just as a sanity check, what is a typical vacuum reading on your meter? if it translates to less than a few feet of displaced water, I am very interested in trying this and reporting back to you.

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WingAdmin
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Re: How to synchronize your carburetors

Post by WingAdmin » Tue Jul 26, 2016 9:09 pm

tylers883 wrote:great instructional!

WingAdmin, I have a question for you, please respond when you have time...

I'd like to solve the error problem by substituting the vacuum meters with manometers( ie vertical displacement of water in a tube). All manometers, regardless of tube diameter and volume, will inherently report the same vacuum or pressure. There is a physics 101 explanation to this that I care not to learn about, so please dont ask me to repeat it - LOL.

Anyway, just as a sanity check, what is a typical vacuum reading on your meter? if it translates to less than a few feet of displaced water, I am very interested in trying this and reporting back to you.
I also have a set of manometers...that I have yet to use, as I haven't synced carbs in so long! :)

I wish I could remember what I was pulling...I'm guessing somewhere in the range of 5 inches Hg?

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tylers883
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Re: How to synchronize your carburetors

Post by tylers883 » Wed Jul 27, 2016 10:52 am

1 inch of water converts to 0.0734824 inches of Hg.

ie 5inches of Hg translates to 68 inches of water

This means I could build a water based manometer in the 68 inch or taller range. This is not very practical but it is doable.

Oh well. I will have pass on this idea. I don't want to store a manometer that big.

Thank you!

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tylers883
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Re: How to synchronize your carburetors

Post by tylers883 » Wed Jul 27, 2016 11:08 am

Just a quick question.

If I were to sync the carbs 'by ear' would you recommend this or do I risk just making it worse?

When I say 'by ear', I mean that I would adjust the screw until it runs rough, then I would adjust it again in the other direction until it runs rough, then select an adjustment in the middle. I would do this to each carb, then repeat until it sounds as best as I could get it.

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virgilmobile
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Re: How to synchronize your carburetors

Post by virgilmobile » Wed Jul 27, 2016 8:00 pm

No.Carb 3 is set by the throttle plate.Carb 1 is balanced to it.
Carb 2 and 4 are balanced together..then left and right are balanced.
When the carb is synced and each carb adjusted it will not go worse-better then worse with a middle point.
It starts with low fuel and just gets more as each one is opened up.
I've tried the by ear method.Even using a stethoscope to listen to the carb to set the throttle plates the same opening time.
It was a bit better but a vacuum check proved it was off noticeably.
I do adjust the sync with the engine holding at 1000 rpm.Right where it counts the most,then idle it back down when finished.
This proved best on a older engine that didn't have exactly the same compression on each cylinder.
Absolutely get the vacuum as close as possible across the board at The 1k mark.
I didn't use vacuum gauges for mine..They fluttered enough to be annoying to work with.
I opted for my own cheap design using 4 bottled oil containers.Using the tube of water didn't appeal to me and oil in a tube was bad too.First start up sucked the oil the cylinder too easy.I use a bottle to collect the oil and the vacuum to pull it back out.No oil can get into the vacuum lines.Monitering oil level was easier than watching gauges and just as accurate

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chief771
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Re: How to synchronize your carburetors

Post by chief771 » Sat Apr 06, 2019 4:18 pm

Thank you very much for posting this article. It makes this process so much easier. I do have a question. What should the gauges read when they are hooked up to the carbs? Every gauge registered the same or very close but the needle does not move much at idle. Where should the needle be pointing?
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Re: How to synchronize your carburetors

Post by jmwols@aol.com » Mon May 13, 2019 7:46 pm

Do we leave the brass fittings open on the intakes will checking the sync on the others.
Ex. Hook up 3 and 4 a d checking sync.
Left 4 and 2 brass fittings open or plug it?
Will checkin 2 and 4 sync. Plug 3 and 4 or not?
JM

Rambozo
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Re: How to synchronize your carburetors

Post by Rambozo » Mon May 13, 2019 10:58 pm

Plug any that do not have a gauge hooked up. Better yet, look up a few posts for the fish tank manifold so you don't have to keep swapping hoses if you don't have four gauges.

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Re: How to synchronize your carburetors

Post by jmwols@aol.com » Mon May 13, 2019 11:08 pm

Thank you Rambozo! I got the bike cheap less then $700 but needed carbs done and fix lights. So this hoepfully is the last of it. Of course have ti change oil and filter anf adjust valves. Maybe timing belt?
Thanks again.
Jm

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Re: How to synchronize your carburetors

Post by Rambozo » Mon May 13, 2019 11:22 pm

The list goes on and on. :lol:

Have fun.

TerraKacher
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Re: How to synchronize your carburetors

Post by TerraKacher » Wed Jun 12, 2019 2:04 am

I have a gl1100i 1980, I'm having a hard time keeping the idle going without it dying on me. I checked the sync today and the gauges were almost the same all four. But the reading was very low compared to the video that was at the beginning of this thread, like 2-5 on the outside of the dial. Still very much in the red. I just rebuilt the carbs, new plugs, new belts, check compression 90-110. Good spark.

I have to screw in the curb idle adjustment all the way just to keep a low idle, runs better with the Choke partially on. In a few more days, I will be getting the screw driver that has the bend at the end for adjusting the fuel mixture screws.

Any idea as to why I had low vacume and won't idle?

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Re: How to synchronize your carburetors

Post by TerraKacher » Fri Aug 16, 2019 1:16 am

After rebuilding my carbs and with new float needles. I hooked up the four gauges to sync the carbs, and this is what I showing. I checked all my fittings connections and everything appears to be tight. All the clamps around the intake boots are tight, all the bolts are tight. But #1 seems to not be moving at all or at least no where close to the other three. When I open the vacume valve all the way, the needle does flutter a little, but it stays around the zero mark.


Any idea's of what to do? I tried opening the gauge valve all the way until it unscrewed, and but it back in. no change.

Now the only thing I haven't done and probably should of by now is adjust the valves.

Friday, I'm going to check for spark, and do a compression test on #1. And might as well adjust or check the valves while I'm at it.

Any suggestions would be greatly appreciated.

TerraKacher
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Re: How to synchronize your carburetors

Post by TerraKacher » Sat Aug 17, 2019 9:44 pm

virgilmobile wrote:
Wed Jul 27, 2016 8:00 pm
First start up sucked the oil the cylinder too easy.I use a bottle to collect the oil and the vacuum to pull it back out.No oil can get into the vacuum lines.Monitering oil level was easier than watching gauges and just as accurate
I'm trying to visualize what you are saying and I'm having difficult time. Do you have a picture of the oil setup?

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virgilmobile
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Re: How to synchronize your carburetors

Post by virgilmobile » Sun Aug 18, 2019 9:29 am

I'll see if I can find my pictures

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virgilmobile
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Re: How to synchronize your carburetors

Post by virgilmobile » Sun Aug 18, 2019 10:54 am

Have a look through this.
viewtopic.php?f=16&t=8994



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