Carb vacuum balancing question.

[bushyb]

Thanks very interesting. I Googled the Uni-syn and found this.





http://www.theminiforum.co.uk/forums/topic/181844-recommend-me-a-carb-balancing-tool/

[supershaft]

Except that none of them are manometers.

[_cy_]

Originally Posted by bushyb

Thanks very interesting. I Googled the Uni-syn and found this.

http://www.theminiforum.co.uk/forums/topic/181844-recommend-me-a-carb-balancing-tool/

Uni-syn have been used for balancing multi-carbs for decades. old british sports cars almost all came with side draft carbs.

the old Stromberg side draft carbs are almost same size/shape of Bings.

[supershaft]

IMO a properly damped, good manometer can't be beat. They are THE scientific standard. They are in fact Mother Nature showing you what is going on.

[_cy_]

Originally Posted by supershaft

IMO a properly damped, good manometer can't be beat. They are THE scientific standard. They are in fact Mother Nature showing you what is going on.

if you had used a Uni-syn much, then you would realize that a Uni-syn is a variable throat size dampened manometer.

as flow goes across veritable sized opening so one can measure all RPM range. air movement moves a plastic floater, which is dampened by it's own weight. if one wants to know air flow/volume of one carb is higher, lower or same as another carb. Uni-syn will reveal it for any RPM. don't be fooled by Uni-syn's low $25 costs. this is a quality tool that used to be the standard for balancing side draft carbs on old British Sports cars.

which is exactly how this Bacharach model MZF Draft Gauge works (from my manometers used for HVAC)

[supershaft]

I have used them before. I would much rather use a manometer on our bikes or cars. A Uni-syn is a manometer and a mechanical contraption in one. A manometer itself is neither mechanical or electronic. Therein lies their accuracy and simplicity. Why use a contraption when you can use THE scientific standard that IMO is not only more accurate but easier to use? I am just putting another angle out there for readers to ponder.

[_cy_]

Originally Posted by supershaft

I have used them before. I would much rather use a manometer on our bikes or cars. A Uni-syn is a manometer and a mechanical contraption in one. A manometer itself is neither mechanical or electronic. Therein lies their accuracy and simplicity. Why use a contraption when you can use THE scientific standard that IMO is not only more accurate but easier to use? I am just putting another angle out there for readers to ponder.

Uni-syn is equally accurate to any conventional manometer. the only mechanical part is throat size opens and closes to compensate for higher or lower air flow for different RPM ranges.

which brings up a major advantage of Unisyn. it's ability to measure air flow for high and low RPM with same sensitivity. vs a conventional manometer using a wider range, less sensitive meter to cover high and low RPM. so technically Uni-syn is more accurate than a conventional wide range manometer. difference is so small one is splitting hairs...

draw back to Uni-syn is one cannot mount two like manometers and monitor air flow while riding. now we are splitting more hairs ... as objective is for both carbs to flow same volume of air. which Uni-syn does equally accurate to any conventional manometer with same or less fuss.

[bushyb]

This turned out quite a good topic with a lot of good comments from several experts, ending up discussing manometers!!!!!!!.......
Well I suppose I could start a new topic.... well let’s see what the opinions will be as it is related.

Cable adjustment on throttle and choke.

I have briefly read a few articles on tuning and adjusting the cables....
Now this is where it gets difficult to describe and maybe test.
Let’s assume the carbs are tuned, balanced, cables adjusted and synchronised etc.
I believe that there should be some sorts of test or check preformed to confirm your adjustments you have just made are correct other that riding.

When opening the throttle fully open on the handle bar how do you know that the carb is opening up all the way? Is there a check that can be performed other that using you finger to pull up the throttle lever or cable to check that it is opening all the way up to the maximum or stop lever?

I would have thought if the pipes from the air filters were disconnected at the time of doing adjustments then you could look in the back end of the carb you would be able to see the opening and closing of the butterfly as the throttle is twisted. (Assuming that going beyond this point would be closing the flow of air???) Once the butterfly reaches the midpoint or the horizontal position in the throat that this would be the fully open throttle position even though there was still room to move the lever or cables more upwards as if to accelerate more. Please give me your thoughts.

Similarly what would the test be to check adjustment on the choke cable? For example the handle bar lever is moved to the 1/2 choke position. What position must the start valve be in? Also for the fully cocked lever position, how do you check that the start valve is where it is supposed to be?

So in a nut shell will it make any difference once these cables are set and there is still the possibility that not all the possible movement has not been taken up.

[supershaft]

Originally Posted by _cy_

Uni-syn is equally accurate to any conventional manometer. the only mechanical part is throat size opens and closes to compensate for higher or lower air flow for different RPM ranges.

which brings up a major advantage of Unisyn. it's ability to measure air flow for high and low RPM with same sensitivity. vs a conventional manometer using a wider range, less sensitive meter to cover high and low RPM. so technically Uni-syn is more accurate than a conventional wide range manometer. difference is so small one is splitting hairs...

draw back to Uni-syn is one cannot mount two like manometers and monitor air flow while riding. now we are splitting more hairs ... as objective is for both carbs to flow same volume of air. which Uni-syn does equally accurate to any conventional manometer with same or less fuss.

Funny. I think they are lot more fuss for a lot less return. I would rather use a plain ol' manometer any day over one. They are less accurate for there super short tube. They aren't more accurate for more or less air rather more or less throttle position but then that is debatable because they measure more throttle but they are flowing the same air as before and not measuring more throttle flowing more air which is really the whole point of more throttle. Closing the throat insures the same amount of air as with the throat more open although the throttle is open more thusly really measuring the same amount of air. A regular manometer measures what is really going on in real time. They can't be beat IMO. If a Uni-syn works better for you more power to it but don't blame the manometer. There are reasons why just about every tuner out there uses a manometer or an electronic gadget that mimics a manometer over Uni-syn's. Whether or not they are connected to the carbs or a flow bench.

[_cy_]

Originally Posted by supershaft

Funny. I think they are lot more fuss for a lot less return. I would rather use a plain ol' manometer any day over one. They are less accurate for there super short tube. They aren't more accurate for more or less air rather more or less throttle position but then that is debatable because they measure more throttle but they are flowing the same air as before and not measuring more throttle flowing more air which is really the whole point of more throttle. Closing the throat insures the same amount of air as with the throat more open although the throttle is open more thusly really measuring the same amount of air. A regular manometer measures what is really going on in real time. They can't be beat IMO. If a Uni-syn works better for you more power to it but don't blame the manometer. There are reasons why just about every tuner out there uses a manometer or an electronic gadget that mimics a manometer over Uni-syn's. Whether or not they are connected to the carbs or a flow bench.

good grief .... talk about beating a dead horse... how many times do you want to discuss the same thing?

BS a plain manometer is more accurate. they are essentially the same in accuracy, with Unisyn being slightly more for reasons stated above.
what a std manometer is better at is being able to look at a gauge in a remote location. which is better suited for a tuner because they are running motor, making changes looking for real time feedback.

a Uni-syn is a tool that measures air flow allowing anyone to quickly balance their carb for dirt cheap ($25)
don't remember claiming Uni-syn was the best tool for everyone. it's just another tool that works well.

[robtg]

Uni-syn is great for some carbs. However the air inlets for the main jets,
idle jets, and vent under the diaphragm are blocked when Uni-syn is used.
Great tool, but not for Bing CVs.

[_cy_]

Originally Posted by robtg

Uni-syn is great for some carbs. However the air inlets for the main jets,
idle jets, and vent under the diaphragm are blocked when Uni-syn is used.
Great tool, but not for Bing CVs.

works great with Bing carbs .. simply turn intake tube to take a reading with Uni-syn. with correct adapters ALL multi-port air flow/volume can be measured/balanced, provided adjustment are possible.

it's normal to make adapters to use Uni-syn. but most side draft carbs will not need one, unlike Bings. let's say you need to balance dual down draft Webers on a 911 Porsche or what ever. simply make an adapter to fit to Uni-syn.

again Uni-syn is not for everyone, but it's a quality/versatile tool to have in your toolbox.
please excuse the dirt.. been running R80G/S pretty hard


drag racing at Zombie Apocalypse Training Camp

[robtg]

Originally Posted by _cy_

works great with Bing carbs .. simply turn intake tube to take a reading with Uni-syn. with correct adapters ALL multi-port air flow/volume can be measured/balanced, provided adjustment are possible.

it's normal to make adapters to use Uni-syn. but most side draft carbs will not need one, unlike Bings. let's say you need to balance dual down draft Webers on a 911 Porsche or what ever. simply make an adapter to fit to Uni-syn.

again Uni-syn is not for everyone, but it's a quality/versatile tool to have in your toolbox.
please excuse the dirt.. been running R80G/S pretty hard




drag racing at Zombie Apocalypse Training Camp

I stand corrected. Your "adapter" would work fine.--RG

[supershaft]

Now we're getting somewhere. Of course they work but I could sync my carbs better with my manometer before you gets your snorkels off let alone back on.

[bushyb]

Originally Posted by bushyb

This turned out quite a good topic with a lot of good comments from several experts, ending up discussing manometers!!!!!!!.......
Well I suppose I could start a new topic.... well let’s see what the opinions will be as it is related.

Cable adjustment on throttle and choke.

I have briefly read a few articles on tuning and adjusting the cables....
Now this is where it gets difficult to describe and maybe test.
Let’s assume the carbs are tuned, balanced, cables adjusted and synchronised etc.
I believe that there should be some sorts of test or check preformed to confirm your adjustments you have just made are correct other that riding.

When opening the throttle fully open on the handle bar how do you know that the carb is opening up all the way? Is there a check that can be performed other that using you finger to pull up the throttle lever or cable to check that it is opening all the way up to the maximum or stop lever?

I would have thought if the pipes from the air filters were disconnected at the time of doing adjustments then you could look in the back end of the carb you would be able to see the opening and closing of the butterfly as the throttle is twisted. (Assuming that going beyond this point would be closing the flow of air???) Once the butterfly reaches the midpoint or the horizontal position in the throat that this would be the fully open throttle position even though there was still room to move the lever or cables more upwards as if to accelerate more. Please give me your thoughts.

Similarly what would the test be to check adjustment on the choke cable? For example the handle bar lever is moved to the 1/2 choke position. What position must the start valve be in? Also for the fully cocked lever position, how do you check that the start valve is where it is supposed to be?

So in a nut shell will it make any difference once these cables are set and there is still the possibility that not all the possible movement has not been taken up.

Thanks guys. Holy smoke, that went well and well.... What about the second part of the question?