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Carb Syncing


kamp0ss

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Alright, so I just followed a video on how to sync the carbs, and it seemed pretty easy so I did it!

(This was with out it running, and without the pressure checker.)

 

So I took off the air filter box and the sliders lined up with the throttle all the way in, so I moved on

to adjusting the sliders free play. As I pressed the throttle in the right one started a little before the left

so I adjusted it, and I got it literally perfect so I tightened the screws back up (TORS removed).

 

I put everything back together, hooked up the gas and air box, put the plastics on (I was convinced I

would be done). Pulled it out of my garage, fired it up, and for some reason the compression seemed

stronger coming out of the right exhaust pipe, but once it warmed up it seemed even for the most part.

 

I rode it around my yard real slow as it warmed up, just listening to it and feeling the throttle, which in my

opinion had better response. I could be wrong though haha. Anyways, it was running pretty well when on

the throttle, so I brought it back to my garage and watched it idle and the right exhaust was making

subtle crackling sounds. I asked my cousin what it could be and he said either bad gas/oil mix or the airflow

was off. I run 40:1 and it was running very good in my opinion, so I canceled that option out. I am left

to believe the airflow is my problem. He also mentioned it will need a tune up now since the carbs have

been synced. Is this correct or could there be other problems? I believe I hooked my air filter box up the

same way it was before, so I doubt that would be the problem.

 

Can someone tell me how to check my airflow or show me a video of how to do a tune? I recently took a

small engine class, and am real bad at tuning one of those, so the easier you make it for me the better!

 

I have many more questions to ask about this, but don't want to keep typing because I doubt members

will want to read this much lol.

 

Thanks

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I would first check your air screws and make sure they are adjusted the same on each side.

 

As for your cousin saying you need a tune up after syncing your carbs, what "tune up" is he talking about? After you sync carbs you don't need to tune anything up :blink: .

 

Adjusting your carbs slides by eye works.....but it won't get it exact. The only way to know they are 100% perfect is to use a sync tool IMO. http://www.farmandsandtoys.com/partdetail.asp?partid=59

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I would first check your air screws and make sure they are adjusted the same on each side.

 

As for your cousin saying you need a tune up after syncing your carbs, what "tune up" is he talking about? After you sync carbs you don't need to tune anything up :blink: .

 

Adjusting your carbs slides by eye works.....but it won't get it exact. The only way to know they are 100% perfect is to use a sync tool IMO. http://www.farmandsandtoys.com/partdetail.asp?partid=59

 

 

He meant tune the idle. For air flow.

 

If I get that tool how do I use it? What numbers do I want it to read at. Any videos or instructions with it?

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If I get that tool how do I use it? What numbers do I want it to read at. Any videos or instructions with it?

 

its simple....you remove the air filter first. then you start the bike and take the tool and hold it to the intake horn of the carb and put slight pressure on it to seal the carb with the tool forcign the air to be sucked in through the tool. it will raise a needle and give you a reading of a certain number. There isn't a specific number that you are looking for.....what you are looking for is to "sync" the carbs....to make sure both carbs are sucking the same amount of air...which is done by tuning the carbs so that the tool reads the same number for both carbs.

 

there are videos on youtube about how to tune the banshees...

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its simple....you remove the air filter first. then you start the bike and take the tool and hold it to the intake horn of the carb and put slight pressure on it to seal the carb with the tool forcign the air to be sucked in through the tool. it will raise a needle and give you a reading of a certain number. There isn't a specific number that you are looking for.....what you are looking for is to "sync" the carbs....to make sure both carbs are sucking the same amount of air...which is done by tuning the carbs so that the tool reads the same number for both carbs.

 

there are videos on youtube about how to tune the banshees...

 

So it doesn't matter if they both read 7 or both only read 3? I saw a video and the guy did it with the gas on a little bit, and I believe he was tightening the tops of the carbs to make them in sync. I don't quite understand this because they could be synced with suction but they may not be synced with the throttle, does this make sense?

 

Then in the video he had it idleing and was changing the screws on each cylinder to match. What I don't understand, again, is how you can match them but still know you are where you want to be if you don't have a set number. They can both idle really high and match or idle low and match. Can someone clear this up?

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i get what your saying......but in reality its about the carbs being matched to each other. You set the idle and then you sync them. this is so that they are both flowing the same amount of fuel and same amount of air at the same time.

 

the guy that showed cranking down the tops of the carbs was adjusting the slides inside of the carbs via the cable nuts that are on the top of the carbs....if you don't adjust the slides (which is what restricts the air) then how are you supposed to get a reading on the sync tool? haha.....your meausing the flow of air into the carb and matching it so that both slides and air screws are adjusted so that they both match exactly with how they are sucking air...

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i get what your saying......but in reality its about the carbs being matched to each other. You set the idle and then you sync them. this is so that they are both flowing the same amount of fuel and same amount of air at the same time.

 

the guy that showed cranking down the tops of the carbs was adjusting the slides inside of the carbs via the cable nuts that are on the top of the carbs....if you don't adjust the slides (which is what restricts the air) then how are you supposed to get a reading on the sync tool? haha.....your meausing the flow of air into the carb and matching it so that both slides and air screws are adjusted so that they both match exactly with how they are sucking air...

 

 

Alright, so what I did the other day was adjust the slides. And to my eye they are perfect. So when I use this tool is there a certain number I am trying to match the two carbs at? Do I give it a little gas and adjust the slides, then let it idle and adjust the idle? There has got to be a certain number for the idle at least, I am assuming.

 

I just don't understand how the sliders move at exactly the same time but would not have the same air flow rate, other than by a small decimal. My final question is, often one slide raises before the other, so when I am using the sync tool how do I test for this? Or am I supposed to adjust slides by eye first to get them moving at the same rate and then use the sync tool after to get the airflow correct?

 

Thanks for your help, I appreciate it.

Edited by kamp0ss
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there is not a certain number you are trying to obtain on the sync tool! There cant be. think of it this way.......they are rated for 26mm carbs all the way to a 41mm carb. Those flow different amounts......all it is made to do is get your carbs running exactly the same so your not feeding one cylinder with more air/fuel than another. whenever you adjust anything on any carb you should always at least blip the throttle before you take any measurments (to clear the carbs).

 

The slides move up and down changing the amount of vacuum coming through the venturi in the carb......as the air is drawn in it sucks the fuel from the carb and mixes it in mid flight...

 

there is an air screw and also slides and needle positions and jets that are all inside of a carb......even though they are supposed to be the same they can be off by JUST a tiny little bit......hell.....ask the guys on here......there's not a damn banshee motor out there that is an exact match to another one...

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Get the tool, set your idles so that they are the same on each carb (DOESNT matter what # , just as long as they are the same and you like the idle speed).

Then raise rpm up a bit (so that both slides are pulling up a tad) and measure again. Make adjustments to cable adj. so that #s are the same. Done! : )

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Get the tool, set your idles so that they are the same on each carb (DOESNT matter what # , just as long as they are the same and you like the idle speed).

Then raise rpm up a bit (so that both slides are pulling up a tad) and measure again. Make adjustments to cable adj. so that #s are the same. Done! : )

 

 

I did, actually just bought the tool from you guys at F.A.S.T

 

My left carb idels and runs mint, can I just adjust the right one to match it? Or do I gotta start from scratch with the idle?

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Please call us and we will run through it with ya..

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