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Discussion Starter #1
If you read my previous posts you might remember that after fixing a leak in the carburetor, the engine started making popping sounds, especially when slowing down and less when standing, but not when riding steady or speeding up. I checked for vacuum leaks and other suggestions which all came back negative. A few days ago I read a post describing a similar issue and found out my carb is actually not synced. I tried doing it by using some advice (the "red neck" method it was called) which although made the popping go away, now the engine chokes when it speeds up.
So, I'm assuming I farked things up and want to use a monometer to adjust it correctly.
I searched Amazon and found a few options (see one example in the link below). But when I enter the details of the motorcycle, it writes that it isn't compatible. Is it really not compatible? Do you have any suggestion for a monometer which will not cost more than taking the bike to the shop (and I'm not going to build one myself although it is cheapt and relatevily simple).

Thanks

Here is the link : https://smile.amazon.com/ALPHA-MOTO...=1605568644&sprefix=monometer,aps,536&sr=8-15
 

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I made a carb balancer using a wooden yardstick and a length of clear hose filled with engine oil.

Connect each end of the hose to a carb nipple and start the engine. Adjust the sync screw until the two columns are equal. Stop the engine and disconnect the hoses.

A heavier oil will slow the pulses to a more manageable level.

 

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Discussion Starter #3
I made a carb balancer using a wooden yardstick and a length of clear hose filled with engine oil.

Connect each end of the hose to a carb nipple and start the engine. Adjust the sync screw until the two columns are equal. Stop the engine and disconnect the hoses.

A heavier oil will slow the pulses to a more manageable level.

Interesting. But I do have a couple of questions :
How tall should it be?
Did you keep it level as in the picture and connected extensions tubes to it or did you attach these hoses directly to the bike?

Thanks
 

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Interesting. But I do have a couple of questions :
How tall should it be?
Did you keep it level as in the picture and connected extensions tubes to it or did you attach these hoses directly to the bike?

Thanks
The wood support is a yardstick of 3'. The hoses are long enough to loop at the bottom of the yardstick and then connect to the carbs directly. I think it's about 10 to 12 feet of hose. Put enough oil in the hose for it to come about 1/2-2/3 way up the stick. Do keep the stick vertical while using it.
 

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I made a similar one when I had a carb'd bike. but I used water and from the looks of bikerbill's, I used slightly more narrow tubing and made it about twice as high. The water and narrow tube make it much more sensitive because the water is less viscous than oil. I prefer the fast response of water over oil. If you can get the water even and barely pulsing, you have a nicely balance set of carbs.

You can always try water first, then dry the tubing with some air and switch to oil if you decide water is too sensitive, but you can't easily go the other way. Both oil and water make it more sensitive than mercury manometers because they are so much lighter than mercury resulting in a much higher shift when the carbs are not balanced.
 
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$40 for that kit is a nice price for what you're getting. Gauges like that have the benefit of that you can lay them across the seat to view, they don't have to be held vertical as do liquid filled tubes. Also the adapters are typically drilled with small orifices that dampen the vacuum pulses, it also looks like the adapter are threaded in the two most typical pitches used for vacuum gauge ports which will save you the effort of locating or fabricating suitable fittings.
 

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Discussion Starter #7
$40 for that kit is a nice price for what you're getting. Gauges like that have the benefit of that you can lay them across the seat to view, they don't have to be held vertical as do liquid filled tubes. Also the adapters are typically drilled with small orifices that dampen the vacuum pulses, it also looks like the adapter are threaded in the two most typical pitches used for vacuum gauge ports which will save you the effort of locating or fabricating suitable fittings.
All true, but it said it doesn't fit the model according to Amazon. So what does?
 

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All true, but it said it doesn't fit the model according to Amazon. So what does?
What size/pitch and location are the ports for your gauge attachment. It comes with fittings that thread into M5x.08 and M6x1.0
Those are pretty common, as are stubs that have rubber caps that you just slip hoses over. Perhaps someone here can comment on the attachment point details. These may just fit after all.
 

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Discussion Starter #9
What size/pitch and location are the ports for your gauge attachment. It comes with fittings that thread into M5x.08 and M6x1.0
Those are pretty common, as are stubs that have rubber caps that you just slip hoses over. Perhaps someone here can comment on the attachment point details. These may just fit after all.
I'm actually not worried about the attachments. They are the standard size as far as I can understand.
But I don't know why they marked it as not compatible with the model. I know it doesn't cost hundreds of dollars, but I prefer not to spend money on something that might not work. That is why I posted here. To see if anyone actually tried it or a different model, on this Vulcan model.
 

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The pictured attachment fittings are one long and one short of each thread type. That's to allow for the possibility that the fitting holes on the manifolds are angled to go to one side of the bike. If the holes on the 500 manifolds are tapped to go one to each side then the one will stick out a bit farther on one side than the other.
If the fittings thread in then there's no reason they shouldn't work.
The way you perform the adjustment is you either remove or lift the tank enough to have room to access the carb linkage adjustment screws. You can either use a small temporary tank, add longer gas lines to the stock tank to relocate it or rotate it around so that it rests on the seat and is not in the way.
Remove the manifold fitting screws and install the provided fittings, hook up the hoses to the gauges. Start the engine, allow it to reach operating temp and develop a smooth idle.
At that point the vacuum on each side should be equal. If not adjust the linkage screws to achieve that condition.
Note that you only want to perform this adjustment AFTER you have adjusted the valve lash and not before as this will directly affect your readings.
Occasionally blip the throttle slightly and allow it to resettle to verify that it is correctly done and lock the linkage adjustment locknuts, turn off the bike, remove the hoses, fittings and reinstall the hole screws.
It's not rocket science. If the fittings fit there's no reason the gauges shouldn't work, they're not "brand specific"
 

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Discussion Starter #11
The pictured attachment fittings are one long and one short of each thread type. That's to allow for the possibility that the fitting holes on the manifolds are angled to go to one side of the bike. If the holes on the 500 manifolds are tapped to go one to each side then the one will stick out a bit farther on one side than the other.
If the fittings thread in then there's no reason they shouldn't work.
The way you perform the adjustment is you either remove or lift the tank enough to have room to access the carb linkage adjustment screws. You can either use a small temporary tank, add longer gas lines to the stock tank to relocate it or rotate it around so that it rests on the seat and is not in the way.
Remove the manifold fitting screws and install the provided fittings, hook up the hoses to the gauges. Start the engine, allow it to reach operating temp and develop a smooth idle.
At that point the vacuum on each side should be equal. If not adjust the linkage screws to achieve that condition.
Note that you only want to perform this adjustment AFTER you have adjusted the valve lash and not before as this will directly affect your readings.
Occasionally blip the throttle slightly and allow it to resettle to verify that it is correctly done and lock the linkage adjustment locknuts, turn off the bike, remove the hoses, fittings and reinstall the hole screws.
It's not rocket science. If the fittings fit there's no reason the gauges shouldn't work, they're not "brand specific"
Thanks. I actually know how to sync the carbs and it is even simpler than what you wrote on the Vulcan 500 (at least the 2009). But what is really important is that you say that the gauges are not brand specific. Thanks.
 

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Thanks. I actually know how to sync the carbs and it is even simpler than what you wrote on the Vulcan 500 (at least the 2009). But what is really important is that you say that the gauges are not brand specific. Thanks.
You're welcome. Gauges measure vacuum, or basically suction as opposed to pressure. Mechanically inside they're very similar in construction, these just work in reverse. There are actually some that work in both directions and will measure vacuum or pressure with "0" as the resting point.
They're graduated typically in Inches or perhaps Millimeters of Mercury as standard, but as you can see from the home built examples above about any fluid is usable.
The liquid filled types must be kept vertical while in use, round gauges aren't liquid filled and can be used at any angle. Whatever the motorcycle brand they all can use the same gauges as long as you have fittings or adapters to attach them.
 

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Discussion Starter #13
Update.
I bought the one I linked jere before.
Worked like a charm. The bike runs so smooth now!

Thanks all for helping.
 

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If you read my previous posts you might remember that after fixing a leak in the carburetor, the engine started making popping sounds, especially when slowing down and less when standing, but not when riding steady or speeding up. I checked for vacuum leaks and other suggestions which all came back negative. A few days ago I read a post describing a similar issue and found out my carb is actually not synced. I tried doing it by using some advice (the "red neck" method it was called) which although made the popping go away, now the engine chokes when it speeds up.
So, I'm assuming I farked things up and want to use a monometer to adjust it correctly.
I searched Amazon and found a few options (see one example in the link below). But when I enter the details of the motorcycle, it writes that it isn't compatible. Is it really not compatible? Do you have any suggestion for a monometer which will not cost more than taking the bike to the shop (and I'm not going to build one myself although it is cheapt and relatevily simple).

Thanks

Here is the link : https://smile.amazon.com/ALPHA-MOTO...=1605568644&sprefix=monometer,aps,536&sr=8-15
Carbs out is sync will not cause your engine to choke while speeding up..one carb opening a little before the other one shows up at idle and small throttle opening conditions.
The easiest way to find out which carb is 'behind'..is to start the engine cold..then just let it idle..the cool exhaust pipe is the carb that needs opened more.
It doesn't necessarily mean it is out of sync it can be a clogged pilot circuit.
Speed up the idle a little... then adust the fuel mix on that side...if it doesn't repond it's a clogged pilot circuit
I would concentrate on fixing that choking on acceleration issue before fine tuning the carbs



Sent from my LM-Q710.FG using Tapatalk
 

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Discussion Starter #15
The problem was fixed by the sync. I'm not a mechanic but a fact is a fact. I'm not going to tinker with it now that it is running great. But I appreciate the input!
 

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The problem was fixed by the sync. I'm not a mechanic but a fact is a fact. I'm not going to tinker with it now that it is running great. But I appreciate the input!
I must have mis interpreted your symptoms as to be trying to accelerate which I assumed to be opening up the throttle to take off
So your symptoms were low speed symptoms? if the problem is the carbs not being synced
At low speed with one carb ahead of the other..it's dragging the other cylinder along with it..that cylinder is in a coast condition and if it lean you can get popping... Under some circumstances bucking
Sometimes you can get what appears to be popping but is actually just the carb opening up enough to start firing that cylinder.. that cylinder may not hit every time at the butterfly isn't opened enough.
All the sync are slow speed problems.
Let's say we have a one mm gap at the butterfly on one carb and zero on the other.
Twisting the grip a little we now have two mm on one carb and now one mm on the other..one carb is passing twice the air... major difference
Once we open it say 5 mm..the other one would be 4 mm...we can't tell the difference at that point the further we twist the grip the less difference we have in the imbalance..
 
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