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Home made manometer question.

So I took a look at the site http://www.powerchutes.com/manometer.asp and the first thing he states is "The objective of the vacuum measuring carb synchronizer is to see that the vacuum signals from both carbs are the same. It is the difference between the signals and not the actual signals we are interested in" so I could be seeing -15pa on the right side and -10pa on the left and if I got both to the same number would be the goal and it wouldn't matter if I went with the -15pa or the -10pa? I'm not the brightest bulb on the shelf but I do use a Manometer as part of my job but I never thought I could use it to sync my throttlebodies and I'm just trying to grasp it.
 
and it wouldn't matter if I went with the -15pa or the -10pa?

I think you mean use one actual manometer and move it from one side to the other, back and forth.
Sure.
At a given throttle position.
You would have to hold the throttle steady while moving the hose. difficult

Can you get two such manometers? so you can see both sides at the same time?
This would be much easier to implement, but yes, at a given throttle setting, and rpm, the vacuum will be the same on both sides, since all the pertinent parts are identical side-to-side.
 
Am I the only one who hears the Muppets singing when I read the word manometer? :dance Do dooo do do do, manometer, do doo do do, manometer, do dooo do do do, do do do, do do do do do do do do........ :scratch
 
I think you mean use one actual manometer and move it from one side to the other, back and forth.
Sure.
At a given throttle position.
You would have to hold the throttle steady while moving the hose. difficult

Can you get two such manometers? so you can see both sides at the same time?
This would be much easier to implement, but yes, at a given throttle setting, and rpm, the vacuum will be the same on both sides, since all the pertinent parts are identical side-to-side.

Nice! This is what I use at work (energy auditing) and you can see both sides at the same time.
Menometer.jpg
 
$4. same length tubing. works like a charm. could be smaller...

have used this on some waaaayyy out of sync carbs and never sucked the trans fluid into one. simple fast and cheap. I am a Scot so... this fits.

Manometer.jpg
 
Mercury?

I think its still available if you shop, maybe pricey! Its the fluid of choice for measurement devices as this for a century. Very heavy liquid and makes the device reasonable in size to manage. Just don't spill it! I have not bought any mercury in a LONG time, so maybe its not practical anymore. I know a very small amount of it, as in an ounce weighs a LOT and works really well in a gauge as described. Just a much smaller gauge to handle is only real advantage. I use TM today for last 15 years. Randy
 
Mercury??? it's toxic and maybe overkill? suck that into a TB/cylinder and things might get interesting quickly... :)
 
This is my first try at a 2-bottle manometer (cue the muppets). A little more technical to put together than the single tube with ATF, but I liked the way it worked out. I used water with a little food coloring. It was important to only fill each bottle about one-third or so (in case the carbs were so out of balance that all the water ended up in one bottle or the other, the bottle didn't end up overflowing). It was pretty easy to use and the bike is running sweetly with the carbs balanced.:drink

DSCF2514.jpgDSCF2523.jpg
 
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homemade manometer

to reduce the pulsing of liquid in the tubes...an aquarium air valve might be the adjustable restriction to slow the pulsing...years ago I saw such a set up... what do you all think.?
 
coming to this late, but just want to add that the physics of the vacuum does not depend on tube length, but the critical thing is your tubing must not collapse, so it has to be pretty stiff esp where it connects to the brass nipples at the engine.
Aquarium tubing will collapse with heat and make your efforts less than useless.

It seems to me it's easy enough to make the two limbs close to equal so why not. But, it has to stay open during the procedure.

John

PS there's lots of chatter around about the fluid to use within. You're looking for the Goldilocks fluid, not too light, not too thick and visible. ATF works for me using hospital suction tubing swedged on to one foot of vacuum hose--from advance auto and sealed to prevent leaking, sucking air.
 

That is very clever, the most compact solution I've seen!

Those considering using a restriction to damp pulses must be careful.
If one side gets restricted more than the other you'll get a false balance.

Mine uses equal volumes on top to damp pulses.
The sniffer valves you can barely see allow me to let air in so I can keep the fluid in range at the beginning of the process.

http://www.flickr.com/photos/31927430@N06/6190411736/http://www.flickr.com/people/31927430@N06/
 
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