Wildguzzi.com
General Category => General Discussion => Topic started by: gearman on October 25, 2019, 11:57:27 AM
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(https://i.ibb.co/LSXXs8m/IMG-0004.jpg) (https://ibb.co/LSXXs8m)
(https://i.ibb.co/Qr2mYks/IMG-0003.jpg) (https://ibb.co/Qr2mYks)
(https://i.ibb.co/BghzD7X/IMG-0010.jpg) (https://ibb.co/BghzD7X)
(https://i.ibb.co/kxHTChn/IMG-0011.jpg) (https://ibb.co/kxHTChn)
(https://i.ibb.co/XFMQKnZ/IMG-0012.jpg) (https://ibb.co/XFMQKnZ)
(https://i.ibb.co/3z24W0W/IMG-0007.jpg) (https://ibb.co/3z24W0W)
(https://i.ibb.co/qRnW6Rr/IMG-0016.jpg) (https://ibb.co/qRnW6Rr)
(https://i.ibb.co/T2rNMWb/IMG-0014.jpg) (https://ibb.co/T2rNMWb)
I apolagise for the pictures but the thumb nails are so small I cant see what I am putting up. I had 12cm hg with the carbtune on the trike, but only 8 or less on the two wheeler at the same rpm.Wth?The bottles are more sensitive.
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Is there another thread on Wild Guzzi that explains the beer bottle buildup, operation? I generally can see it but would like a bit more info... Cant see the top loop fully, e.g.
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I've never seen the beer bottle. I always used the yardstick, hose, and trans fluid to balance
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The tube over the top acts as a syphon to move fluid from the side with lesser vacuum (higher absolute pressure) to the side with stronger vacuum (less absolute pressure), at some point where the carbs are almost balanced the transfer of liquid will stop and the relative vacuum will be indicated by the liquid height.
I imagine unlike a simple "U" tube manometer it is quite well damped as the inside diameter of the bottles is many times greater than that of the syphon.
It's very clever really :thumb:
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Is there another thread on Wild Guzzi that explains the beer bottle buildup, operation?
Obviously we only need two, but this shows the idea fairly well.
There are other on YT, just search 'DIY Carb Balancer'
https://www.youtube.com/watch?v=0HfrHLmpHCY (https://www.youtube.com/watch?v=0HfrHLmpHCY)
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I've never seen the beer bottle. I always used the yardstick, hose, and trans fluid to balance
Same here
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Obviously we only need two, but this shows the idea fairly well.
There are other on YT, just search 'DIY Carb Balancer'
https://www.youtube.com/watch?v=0HfrHLmpHCY (https://www.youtube.com/watch?v=0HfrHLmpHCY)
Thx.
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I apolagise for the pictures but the thumb nails are so small I cant see what I am putting up. I had 12cm hg with the carbtune on the trike, but only 8 or less on the two wheeler at the same rpm.Wth?The bottles are more sensitive.
Are you meaning mercury compared to mercury?
Valve clearance. Cam profile. Obviously vacuum leak. Ignition timing might (not sure on that).
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I prefer this tool, it measures air flow not the MAP downstream of the slide or throttle plate...No hoses, no liquid, but may not fit into position on a Guzzi without a home made adapter...
(https://live.staticflickr.com/5644/29857925163_64b4ccb997_z.jpg)
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Are you meaning mercury compared to mercury?
Valve clearance. Cam profile. Obviously vacuum leak. Ignition timing might (not sure on that).
Yes both on Carbtune which uses metal rods and springs.What does a stock convert measure in cm/hg?
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The tube over the top acts as a syphon to move fluid from the side with lesser vacuum (higher absolute pressure) to the side with stronger vacuum (less absolute pressure), at some point where the carbs are almost balanced the transfer of liquid will stop and the relative vacuum will be indicated by the liquid height.
I imagine unlike a simple "U" tube manometer it is quite well damped as the inside diameter of the bottles is many times greater than that of the syphon.
It's very clever really :thumb:
I've a question: to the extent that there will always be a head of fluid in the fluid transfer line of the bottle which is transfering fluid to the other bottle - does this mean that strictly, the difference in heights of fluid in the respective bottles (as a mimic of the absolute pressure differences. one cylinder to the other) is not 100% accurate on account of this liquid head?
Now, does it make sense to NOT have really tall bottles, or to make the loop tall, so as to minimize this effect? What if you used, say, two 500 ml (roughly 1/2 quart) Mason Jars... and made the crossover tube as low-profile as possible? Now the resolution likely will go down... if the diameter of the vessle / bottle / jar is large.... versus small diameter, I would guess.
Also, it appears that there are two critical elements... i) that the bottles be really solidly fixed down onto the wooden base (lest they fall over); and ii) you start by adding fluid to only one jar / bottle... say to 3/4's full or 7/8's full. Then you blow into one of the hoses to equalize to the other bottle. That way, if ALL of the fluid transfers to the other side... it still has "freeboard" and will not allow water or water/glycol to be drawn into the engine. 'Real important!
Others... people better at physics than I - please offer your comments!
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I've a question: to the extent that there will always be a head of fluid in the fluid transfer line of the bottle which is transfering fluid to the other bottle -
No, the head of fluid over the top is balanced so its effect is effectively zero, In fact if you were to drill a hole through the glass at the bottoms of the bottle and connect them there it would be the same, the beauty of using the top inverted "U" tube, it saves you having to drill a hole through the glass and seal it. If you were to disconnect the bottles from the bike when one was 3'' higher as long as the syphon was filled the level would slowly come back to the same on both sides.
If the diameter of the vessels was larger it would effectively damp the gauge, it would come to the same levels just take longer.
Manometers are neat devices, you can measure very accurately with them, they are used as a standard by which other gauges are compared.
Yes you are right, the total contents must fit in one jar otherwise there is the possibility of sucking fluid into the engine.
I use just a normal U tube about 3 ft high only I use engine oil, this provides some damping and would burn harmlessly if sucked into the motor albeit with a lot of smoke.
Many manometers have a cork near the top, if the fluid rises up it floats and plugs a valve similar to the float valve in a carb.
Another simple instrument you might find interesting is a Hook Gauge, they can measure extremely low pressures.
I used to teach plant operators to accurately measure low pressure with a length tube and a bottle of water.
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What you are saying, Roy, is that the transfer tube is filled on both sides... and that is why it does not impact matters (re measurement). I should have figured that out... that is how you siphon liquids.... DUH! Brain fa*t.
Cheers!
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I get the impression this is very accurate and hard to set the carbs so they are both at same liquid level. I have mercury containing columns... forget the make.(Motion-Pro?).. but i actually can get bubbles of gasoline condensate in the columns... that ha9s to be purged out with an air containing syringe. I do like the columns though because i can easily adjust throttle cable take-up... seeing immediately which cylinder has less slack in the cable. This water glycol based system does take a moment to react and change level, i would guess...?
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The levels are unimportant, the idea is that you're looking for movement in the levels, between one Bottle and the other.
Zero movement equals perfect balance (equal Vacuum in both Inlets).
I'm pretty sure the Carbtune with the Metal Rods has no Springs involved, they're just Rods in precision Tubes, the more Airflow through the Tubes, the higher they rise.
They're useless for balancing the TBs on the Fuel injected Guzzis (the 8V 1200s at least), as they bounce around like crazy at idle.
I don't think you can beat the Mercury Carbtune set-up for sensitivity.
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A carb tune is measuring the weight of mercury as a standard. Not the weight of some other liquid in a tube or beer bottle. Unless you have a known chemical of equal weight of mercury in tube attached to a scale with the correct index reference points calculated based on the i.d. of the tubing, there is know way to properly set the correct vacuum setting on a carb or set of carbs or f.i. butterflies. Balancing two or more may be possible, but to get the correct idle vacuum setting is very questionable.
The density of water compared to mercury is huge. Over 13-1. Meaning 1 inch on a mercury gage is over 13 inches on a gage with water. You can be out a couple of inches with a light chemical in tubes and still be within tolerance if compared to mercury gages.
Don't fool your self with these homemade balancing systems.
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We used to use mercury in the instrument shops because but it's pretty much banned as being too dangerous nowadays.
Spilling a mercury manometer in your garage would be considered a major environmental disaster these days.
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We used to use mercury in the instrument shops because but it's pretty much banned as being too dangerous nowadays.
Spilling a mercury manometer in your garage would be considered a major environmental disaster these days.
It actually evaporates into the air. Raise the temperature in the area and blow a fan towards the neighbors house should clean up the mess.
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We used to use mercury in the instrument shops because but it's pretty much banned as being too dangerous nowadays.
Spilling a mercury manometer in your garage would be considered a major environmental disaster these days.
When I was a kid, a cousin that was in dental school was always bringing me a vial of mercury to play with.
That explains a lot.. :smiley:
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I remember as a primary grade schooler the kid next door had a bottle of mercury -quick silver- we'd play with it and coat coins with it. I was a little jealous that I didnt have a bottle. The thought crossed my mind that I could break a thermometer to get some but I was never that destructive and didn't like there was enough in there to make it worthwhile.
Were we doing something unhealthy or bad?
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For anyone wanting to try the Corona beer bottles here's a good demo
https://www.youtube.com/watch?v=7D_f05_a74Y
I use a "U" tube manometer filled with engine oil myself but I would give this a try for sure. its compact and self standing.
One thing you might want to do on a Guzzi is finish your hoses off with a short length of rubber otherwise they fall off the nipple when it gets hot.
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A carb tune is measuring the weight of mercury as a standard. Not the weight of some other liquid in a tube or beer bottle. Unless you have a known chemical of equal weight of mercury in tube attached to a scale with the correct index reference points calculated based on the i.d. of the tubing, there is know way to properly set the correct vacuum setting on a carb or set of carbs or f.i. butterflies. Balancing two or more may be possible, but to get the correct idle vacuum setting is very questionable.
The density of water compared to mercury is huge. Over 13-1. Meaning 1 inch on a mercury gage is over 13 inches on a gage with water. You can be out a couple of inches with a light chemical in tubes and still be within tolerance if compared to mercury gages.
Don't fool your self with these homemade balancing systems.
Idle Vacuum Setting?
You're balancing the Carbs/Throttle Butterflies, not setting idle.
Idle Speed is set with the Slide Stop Screw(s) (on Carbs), with E.F.I. it's controlled by the ECU via an Idle Control Valve.
'Balancing' (or 'Synchronising') is just a comparison of Inlet Vacuums, and the adjustment to get them equal.
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Are you not both setting idle mixture on carburetted models (using a combination of highest vacuum achieved and highest engine rpm) - with the Hg columns + ear... and then also adjusting throttle valve take up (play in the cables.... for equality thereof) with the Hg columns?
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Are you not both setting idle mixture on carburetted models (using a combination of highest vacuum achieved and highest engine rpm) - with the Hg columns + ear... and then also adjusting throttle valve take up (play in the cables.... for equality thereof) with the Hg columns?
No the manometer has nothing to do with the mixture AFAIK, it is just used to set the balance.
A manometer or the beer bottles measure the difference in pressure directly
Carbtune sticks or Vacuum gauges measure the difference indirectly
There are many types of manometer, some of them will measure low pressures, fractions of an inch with extreme accuracy.
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When I was a kid, a cousin that was in dental school was always bringing me a vial of mercury to play with.
That explains a lot.. :smiley:
I remember at a school Biology class, the experiment was something to do with germanation I think. There was a glass cylindrical open vessel filled with Mercury and an upturned test tube under partial vacuum. The Mercury rose up the test tube and there was a small gap at the top, in there was some sort of seed or bean
Anyway there was a problem and I can't remember what, but the teacher asked me to literally give here a hand. We were both up to our wrists in Mercury trying to do something, although what is lost in the sands of time, for quite a few minutes.
Given the panic that the stuff generates nowadays I still can't workout how I'm not dead (but perhaps it affected my memory). I know it can have real bad long term affects, so looking forward to that :rolleyes:
As far as U tubes go for balancing I got some unwanted Mercury from my old firm when it went to the receiver and they were junking all sorts.
Years later I managed to find 2 good U tube manometers and then another large single one, both on E-Bay for reasonable money. Now I have a pair, I can use one on each cylinder, or use the large one and connect both cylinders to either side. Before I do use them I check with gauges that the Vacuum is in a range where there is no danger of sucking the stuff through the engine
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No the manometer has nothing to do with the mixture AFAIK, it is just used to set the balance.
A manometer or the beer bottles measure the difference in pressure directly
Carbtune sticks or Vacuum gauges measure the difference indirectly
There are many types of manometer, some of them will measure low pressures, fractions of an inch with extreme accuracy.
I think I'm confused. On my Loops and EV there is a connection in the manifold to hook a gauge to. Isn't that where both styles are hooked up?
RER: I used to use a gauge similar to that, it was a pain to read on my Loops and you had to try to hold the throttle the same when you checked each side. I now have a pair of vacuum gauges instead.
Tom
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I remember at a school Biology class, the experiment was something to do with germanation I think. There was a glass cylindrical open vessel filled with Mercury and an upturned test tube under partial vacuum. The Mercury rose up the test tube and there was a small gap at the top, in there was some sort of seed or bean
Anyway there was a problem and I can't remember what, but the teacher asked me to literally give here a hand. We were both up to our wrists in Mercury trying to do something, although what is lost in the sands of time, for quite a few minutes.
Given the panic that the stuff generates nowadays I still can't workout how I'm not dead (but perhaps it affected my memory). I know it can have real bad long term affects, so looking forward to that :rolleyes:
As far as U tubes go for balancing I got some unwanted Mercury from my old firm when it went to the receiver and they were junking all sorts.
Years later I managed to find 2 good U tube manometers and then another large single one, both on E-Bay for reasonable money. Now I have a pair, I can use one on each cylinder, or use the large one and connect both cylinders to either side. Before I do use them I check with gauges that the Vacuum is in a range where there is no danger of sucking the stuff through the engine
Mercury poisoning is extremely rare with less than 500 deaths annually worldwide. Mostly caused by coal burning and eating fish.
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I think I'm confused. On my Loops and EV there is a connection in the manifold to hook a gauge to. Isn't that where both styles are hooked up?
RER: I used to use a gauge similar to that, it was a pain to read on my Loops and you had to try to hold the throttle the same when you checked each side. I now have a pair of vacuum gauges instead.
Tom
You're right Tom, I think what Roy was driving at is if you use a manometer or the beer bottle device with both sides atached to the ports you are reading the pressure difference between the 2 ports
If you are using gauges or a Carbtune you are measuring the vacuum generated by each intake manifold and to get the difference you need to subtract the difference of the gauge readings or the height of the sticks.
If I use 2 manometers with one side of each attached to each inlet manifold and the other side to atmosphere I'll be measuring the actual vacuum generated by each manifold. So I'll need to subtract the difference of each reading to arrive at the pressure difference between them, therefore I'm not measuring the pressure difference directly, I'm measuring each inlet manifold pressure directly.
If I just use one manometer and attach each side to the 2 inlet manifolds I measure the pressure difference between each manifold directly
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Mercury poisoning is extremely rare with less than 500 deaths annually worldwide. Mostly caused by coal burning and eating fish.
Thanks for that, puts my mind at rest.
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If I understand it right. It appears that both types are measuring the vacuum at the manifold and that it's just two different tools to do the same job.
I think I got it?
Tom
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If I understand it right. It appears that both types are measuring the vacuum at the manifold and that it's just two different tools to do the same job.
I think I got it?
Tom
Kinda right.
You are measuring and calibrating to inches of mercury. Not inches of some other liquid. Mercury is over 7 times heavier than water. The scale marking of a water filled gage would have to be over 7 times greater between marking to equal 1 inch spacing between mercury markings. Also, the i.d. of the column (tubing) determines the spacing on the scale.
There is a specification on what the mercury column weight/height should be on an idling engine. There is a tolerance between two or more intake points also.
If you use a light liquid verse mercury, You could be really close if the two columns (or more on multiple cylinder) with a light liquid and a difference of 5 inches between any of them.
Unless you calculate column/tube i.d., liquid weight, scale spacing ratio, the accuracy of a home made set up is a guess. Go buy some real gages. The new vacuum gages work great.
Save the liquid in a tube for a level between two points.
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Kinda right.
You are measuring and calibrating to inches of mercury. Not inches of some other liquid. Mercury is over 7 times heavier than water. The scale marking of a water filled gage would have to be over 7 times greater between marking to equal 1 inch spacing between mercury markings. Also, the i.d. of the column (tubing) determines the spacing on the scale.
There is a specification on what the mercury column weight/height should be on an idling engine. There is a tolerance between two or more intake points also.
If you use a light liquid verse mercury, You could be really close if the two columns (or more on multiple cylinder) with a light liquid and a difference of 5 inches between any of them.
Unless you calculate column/tube i.d., liquid weight, scale spacing ratio, the accuracy of a home made set up is a guess. Go buy some real gages. The new vacuum gages work great.
Save the liquid in a tube for a level between two points.
Sorry, as someone who spent much of my working life figuring out how to measure stuff in an industrial setup I must take exception.
In the case of a throttle balance manometer we are not really interested in measuring relative to atmospheric pressure just the pressure difference between left and right manifolds and we don't really care about the numbers so we don't need a scale marking. Water is fine for that although I prefer something lighter still, engine oil as it has the added advantage of a high viscosity with it's added damping
Mercury is 13.663 times as dense as water. yes you can if you want to measure inches of mercury using water or oil or any other liquid for that matter.
The ID of the column has nothing to do with it, for a given pressure the fluid rises the same distance up a small tube as a large tube, its pressure and density that matter.
A manometer is a real gauge, it's used as a standard to set Bourdon tube gauges against.
The problem with using Bourdon tube gauges is you now have 2 or more "Gauge pressure" numbers you have to juggle in your head
With a "U" tube manometer you just have a single "Differential Pressure" which you only need to reduce, you are not really interested in the exact magnitude of.
(Changes in red)
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Sorry, as someone who spent much of my working life figuring out how to measure stuff in an industrial setup I must take exception.
In the case of a throttle balance manometer we are not really interested in measuring relative to atmospheric pressure just the pressure difference between left and right manifolds and we don't really care about the numbers so we don't need a scale marking. Water is fine for that although I prefer something lighter still, engine oil as it has the added advantage of a high viscosity with it's added damping
Mercury is 13.663 times as dense as water. yes you can if you want to measure inches of mercury using water or oil or any other liquid for that matter.
The ID of the column has nothing to do with it, for a given pressure the fluid rises the same distance up a small tube as a large tube, its pressure and density that matter.
A manometer is a real gauge, it's used as a standard to set Bourdon tube gauges against.
The problem with using Bourdon tube gauges is you now have 2 or more "Gauge pressure" numbers you have to juggle in your head
With a manometer you just have a single "Differential Pressure" which you only need to reduce
Amen brother :wink: :wink: :wink: :wink:
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Sorry, as someone who spent much of my working life figuring out how to measure stuff in an industrial setup I must take exception.
In the case of a throttle balance manometer we are not really interested in measuring relative to atmospheric pressure just the pressure difference between left and right manifolds and we don't really care about the numbers so we don't need a scale marking. Water is fine for that although I prefer something lighter still, engine oil as it has the added advantage of a high viscosity with it's added damping
Mercury is 13.663 times as dense as water. yes you can if you want to measure inches of mercury using water or oil or any other liquid for that matter.
The ID of the column has nothing to do with it, for a given pressure the fluid rises the same distance up a small tube as a large tube, its pressure and density that matter.
A manometer is a real gauge, it's used as a standard to set Bourdon tube gauges against.
The problem with using Bourdon tube gauges is you now have 2 or more "Gauge pressure" numbers you have to juggle in your head
With a manometer you just have a single "Differential Pressure" which you only need to reduce
Technical manual for multi cylinder, multi carb/injection manifolds have a calibration vacuum number. Not just a balance point. This balance vacuum is usually measured in inches of mercury not water or transmission fluid.
Both pressure and density are factors in how far a liquid will differentiate between intakes. Mercury density is 13.6 times that of water. Your scale for a less dense liquid has to be adjusted accordingly if you are balancing to industry specifications. If you are using a lighter liquid like water in the hose, the levels could be different by 7.8 inches and be the same as 1/2 inches of mercury.
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If you wanted to measure the manifold pressure with a mercury manometer you would need one at least 30 inches high, not that your manifold will pull down that far but if you suddenly apply a Vacumme or pressure to a mercury manometer its very easy to lose the mercury out the top, once it gets moving the momentum would easily carry it much further than you expect.
Most Bourdon tube Vacuum gauges are also calibrated in inches of Mercury (typical 0 - 30"Hg) or the metric equivalent.
Getting back to balancing a set of carbs you don't need such a large scale because you are comparing the vacuums in one manifold to the vacuum in another, (differential pressure) 2 or 3"Hg would be plenty. I use a simple "U" tube about 3 ft tall filled with oil S.G. ~0.8 If I wanted to measure the Vacuum I would need it over 500 inches tall.
I was used to using mercury manometers in an instrument shop setting, they are great where you need a very accurate low pressure up to about 20 psi but they are very easy to spill.
Flour of Sulphur can be used to clean up a mercury spill, it amalgamates and allows it to be swept up.
Mercury can also have an adverse effect on Aluminium as this demonstration shows/
https://www.youtube.com/watch?v=IrdYueB9pY4
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Here you go :evil:
https://www.youtube.com/watch?v=1j-rWz-RmBo
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Hey, what a hoot! Thanks Roy.
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So, using my four column Motion Pro mercury containing manometer (with small orifices in ea. of the tubes... to dampen the responses of the respective mercury columns) the right process is:
- ensure that both heads are up to torque, properly;
- ensure that valves are adjusted;
- ensure that ignition system is healthy, and timed properly... LHS and RHS advance track together properly.
- remove the screw from ea. intake manifold and fit replacement screws with nipples on them to fit manometer hose;
- fit temporary caps onto the respective nipples;
- check to see that there is play in the starting circuit cables... and that there is play in ea. of the two throttle cables (play evident at the carbs).
- warm up bike by riding;
- set up fans to provide cylinder cooling;
- with bike running, in turn, fit one of the hoses to connect the manometer... one onto ea. intake manifold nipple. Two mercury columns remain un-used... and these are set into the "closed" position on the manometer body. Manometer body in general is set to VENT;
- do NOT rev-up /blip throttle on bike with the manometer attached;
- adjust the respective mixture screws for ea. carb to get to max idle speed... and go a wee bit richer (in deference to keeping this aircooled bike a bit cooler);
- adjust idle speed in both carbs... one at a time. For my PHF 30 carbs, do NOT simply turn the srew against the slides. Rather, raise the rpm a wee bit and while raised... screw-in or screw-out the idle speed screw of ea. carb to adjust, to get to equal columns of mercury between the two cylinders with no throttle-grip applied;
- finally, note that a slight application of throttle results in both columns of mercury moving together... not one first, trailed by the other. That adjustment is effected by the the cable terminal adjustment... locknut and cable-end. Ensure that locking the locknut does not change the manometer results!
Do I have this right?
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Do I have this right?
Yes I think so, from idle to say 2000 revs the mercury columns should stay relatively equal but don't worry about a fraction of an inch, it's just about getting the cylinders to share the load.
Manometer body in general is set to VENT; I assume you are referring to the valve to each manifold is open, both sides of the manometer and the reservoir should be under vacuum otherwise you could suck mercury into the motor
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Manometer body in general is set to VENT;[/color] I assume you are referring to the valve to each manifold is open, both sides of the manometer and the reservoir should be under vacuum otherwise you could suck mercury into the motor
The Motion Pro mercury filled manometer comprises a plastic reservoir, into which four plastic-encased glass columns are affixed (at the top). Said glass columns go to the bottom, or well-nigh to the bottom of the plastic reservoir. At the top of each, a rubber tube is attached... and if memory serves, there is an orifice that fits into the rubber tube, there... (or the orifice is in the rubber tube, at the other end... where it attaches to the bike's manifold. There are four rubber tubes, four columns. When the hose is NOT used, at the top of the Motion Pro device there are "nipples" where the un-used hoses plug-in to... so that the mercury does not evaporate-away (which is hazardous). The reservoir, below, has a short hose off the top of the reservoir, and it plugs-in to an air-tight nipple nearby, or a vent-type nipple nearby - which allows the top of the reservoir to be vented to atmosphere when in use.
So, the way I use the device... is the two unused hoses / columns remain attached to the no-vent nipples at the top of the device. The vent on the reservoir gets shifted from Air Tight to Vented to Atmosphere... and the two intended-to-be-used columns / hoses are put onto the manifolds... ONLY once the bike is started-up, warmed up, etc.... At the last moment the manifold-plugs are removed and the hoses are attached.... so as to NOT lose the mercury into the bike's intake tract! No blipping of throttles when attached!
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The Motion Pro mercury filled manometer comprises a plastic reservoir, into which four plastic-encased glass columns are affixed (at the top). Said glass columns go to the bottom, or well-nigh to the bottom of the plastic reservoir. At the top of each, a rubber tube is attached... and if memory serves, there is an orifice that fits into the rubber tube, there... (or the orifice is in the rubber tube, at the other end... where it attaches to the bike's manifold. There are four rubber tubes, four columns. When the hose is NOT used, at the top of the Motion Pro device there are "nipples" where the un-used hoses plug-in to... so that the mercury does not evaporate-away (which is hazardous). The reservoir, below, has a short hose off the top of the reservoir, and it plugs-in to an air-tight nipple nearby, or a vent-type nipple nearby - which allows the top of the reservoir to be vented to atmosphere when in use.
So, the way I use the device... is the two unused hoses / columns remain attached to the no-vent nipples at the top of the device. The vent on the reservoir gets shifted from Air Tight to Vented to Atmosphere... and the two intended-to-be-used columns / hoses are put onto the manifolds... ONLY once the bike is started-up, warmed up, etc.... At the last moment the manifold-plugs are removed and the hoses are attached.... so as to NOT lose the mercury into the bike's intake tract! No blipping of throttles when attached!
Thanks for the description, so you really have 4 individual vacuum gauges with a common reservoir, the glasses must be quite tall since each column is referenced to atmosphere.
The restriction in the hoses is so that if you suddenly apply the vacuum the mercury doesn't rush up the tube well past where it would normally sit and spill out the top, don't ask me how I know.
Many of the industrial ones have a catch pot or a cork valve that slams shut and they are vented outside.
One way to stop the mercury from evaporating is to put a drop of oil on the surface but its ok if you just keep it closed off
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For anyone wanting to try the Corona beer bottles here's a good demo
https://www.youtube.com/watch?v=7D_f05_a74Y
I use a "U" tube manometer filled with engine oil myself but I would give this a try for sure. its compact and self standing.
One thing you might want to do on a Guzzi is finish your hoses off with a short length of rubber otherwise they fall off the nipple when it gets hot.
The guy making the video forgot to mention if using Corona bottles the 1st thing you do is find the nearest serwer and dump out the contents.
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I said that in my OP. :wink:
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Thanks for the description, so you really have 4 individual vacuum gauges with a common reservoir, the glasses must be quite tall since each column is referenced to atmosphere.
The restriction in the hoses is so that if you suddenly apply the vacuum the mercury doesn't rush up the tube well past where it would normally sit and spill out the top, don't ask me how I know.
Many of the industrial ones have a catch pot or a cork valve that slams shut and they are vented outside.
One way to stop the mercury from evaporating is to put a drop of oil on the surface but its ok if you just keep it closed off
The last time I used my manometer set (and indeed, the last few times I used it) I found that their were "gaps" in the columns of mercury... and those gaps varied as to location. They affect the reading accuracy no doubt. It was suggested to me that somehow fuel/gasoline had made its way down the rubber tubes and therefore down some of the glass columns... and it was trapped in the columns... floating on the surface of the Hg when the manometer was not used. In use I have to wonder why or how these slugs of condensate / gasoline could show in the tubes as below some Hg that was higher-up in tube... ? In any case it was suggested to properly "condition" the device for use... one would tilt it over somewhat and in turn for ea. column, take a full 50cc syringe, full of air, and inject that air thru the rubber tube, to bubble to the top of the reservoir. To make this easier you tilt over the column to reduce the head of Hg. This should bubble any impurities of fuel etc out of ea. column.
All: have any of you experienced this? Is my purge process correct?
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I had the same problems with mine - bubbles in the columns. Got a twinmax and the mercury gauge has collected dust ever since. I'm going to try the corona manometer and compare against the electronic. That oughta be interesting.
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If you're using a carbtune make sure to put the restrictors into the tubes else reading it will be far less accurate.
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We used to use mercury in the instrument shops because but it's pretty much banned as being too dangerous nowadays.
Spilling a mercury manometer in your garage would be considered a major environmental disaster these days.
I used to synch my H2 (three carbs) by sticking nails or pencils under the slides and opening the throttle slowly while watching. Not bragging, just establishing a baseline for further assessments of my competency.
And I loaned my store-bought carb-synch tool to a friend who got carried away with the throttle and sucked the mercury into his engine.
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I used to synch my H2 (three carbs) by sticking nails or pencils under the slides and opening the throttle slowly while watching. Not bragging, just establishing a baseline for further assessments of my competency.
And I loaned my store-bought carb-synch tool to a friend who got carried away with the throttle and sucked the mercury into his engine.
I use that method on my 72 Eldorado, it has no taps for a manometer
Oh dear, I hope he was outside.
If you read through your local work safe regulations regarding Mercury it will put you off using it.
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I use that method on my 72 Eldorado, it has no taps for a manometer
Oh dear, I hope he was outside.
If you read through your local work safe regulations regarding Mercury it will put you off using it.
We used to play with it when we were kids , maybe that explains a lot ??
Lead too for that matter, kids are wrapped up in cotton wool these days !!
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I had the same problems with mine - bubbles in the columns. Got a twinmax and the mercury gauge has collected dust ever since. I'm going to try the corona manometer and compare against the electronic. That oughta be interesting.
Can anyone suggest a sure-fire method to i) clean out (what we think is) gasoline liquid / vapour "bubbles" / gaps in the mercury column; and ii) KEEP said gasoline from getting-in to the piping / columns in the first place?
With all of the necessary cautions in dealing with mercury, I imagine you could pour-out (from the reservoir) the mercury and you might be able to strain it through some panty-hose / womens' nylons. You obviously are not straining-out gasoline... but there may be other contaminants that are not liquids. And then, possibly, the gasoline could either leave a varnish (as it flashes-off, or as it "spoils") on the inside of the glass tubes: you could buy a super-long pipe cleaner... to rod-out the columns???? Or a really small diameter wooden dowel... and a rag on same? You would NOT want to lose the rag down the tube, though! What kind of cleaning solvent could aid in cleaning-out the bores of the tubes (bearing in mind that the reservoir itself is plastic - not sure what type, possibly polystyrene?)? If you use the air-in-the-syringe trick to push-out the gasoline, get it to FLOAT on the top of the mercury.... do you even NEED to clean out the bores of the glass tubes?
Do any of you have suggestions. I know that per the post, above, I am NOT the only person experiencing these "bubbles" / gaps in the mercury columns. I have to wonder HOW, with mercury about 15 times more dense than gasoline... HOW it could happily sit ABOVE the gap or bubble? It seems so implausible to me.
I want to save $ (and I like the theoretical accuracy of the Hg columns) - but I know that with bubbles in the columns, they are NOT accurate.
TIA!
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Can anyone suggest a sure-fire method to i) clean out (what we think is) gasoline liquid / vapour "bubbles" / gaps in the mercury column; and ii) KEEP said gasoline from getting-in to the piping / columns in the first place?
I was told by more than one person, that if you put it under a vacuum for a while all would be right again.
i sealed mine up and used my vacuum pump. Left it that way for a few weeks. It never did clear up.
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I was told by more than one person, that if you put it under a vacuum for a while all would be right again.
i sealed mine up and used my vacuum pump. Left it that way for a few weeks. It never did clear up.
Wow... amazed that the stuff is so hard to get rid of!
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Can anyone suggest a sure-fire method to i) clean out (what we think is) gasoline liquid / vapour "bubbles" / gaps in the mercury column; and ii) KEEP said gasoline from getting-in to the piping / columns in the first place?
With all of the necessary cautions in dealing with mercury, I imagine you could pour-out (from the reservoir) the mercury and you might be able to strain it through some panty-hose / womens' nylons. You obviously are not straining-out gasoline... but there may be other contaminants that are not liquids. And then, possibly, the gasoline could either leave a varnish (as it flashes-off, or as it "spoils") on the inside of the glass tubes: you could buy a super-long pipe cleaner... to rod-out the columns???? Or a really small diameter wooden dowel... and a rag on same? You would NOT want to lose the rag down the tube, though! What kind of cleaning solvent could aid in cleaning-out the bores of the tubes (bearing in mind that the reservoir itself is plastic - not sure what type, possibly polystyrene?)? If you use the air-in-the-syringe trick to push-out the gasoline, get it to FLOAT on the top of the mercury.... do you even NEED to clean out the bores of the glass tubes?
Do any of you have suggestions. I know that per the post, above, I am NOT the only person experiencing these "bubbles" / gaps in the mercury columns. I have to wonder HOW, with mercury about 15 times more dense than gasoline... HOW it could happily sit ABOVE the gap or bubble? It seems so implausible to me.
I want to save $ (and I like the theoretical accuracy of the Hg columns) - but I know that with bubbles in the columns, they are NOT accurate.
I suppose you could test-out your cleaning success by using a MityVac on it... to see that the columns remain gap-free.
TIA!
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Sorry, I "quoted" rather than "Modified".
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Can anyone suggest a sure-fire method to i) clean out (what we think is) gasoline liquid / vapour "bubbles" / gaps in the mercury column; and ii) KEEP said gasoline from getting-in to the piping / columns in the first place?
With all of the necessary cautions in dealing with mercury, I imagine you could pour-out (from the reservoir) the mercury and you might be able to strain it through some panty-hose / womens' nylons. You obviously are not straining-out gasoline... but there may be other contaminants that are not liquids. And then, possibly, the gasoline could either leave a varnish (as it flashes-off, or as it "spoils") on the inside of the glass tubes: you could buy a super-long pipe cleaner... to rod-out the columns???? Or a really small diameter wooden dowel... and a rag on same? You would NOT want to lose the rag down the tube, though! What kind of cleaning solvent could aid in cleaning-out the bores of the tubes (bearing in mind that the reservoir itself is plastic - not sure what type, possibly polystyrene?)? If you use the air-in-the-syringe trick to push-out the gasoline, get it to FLOAT on the top of the mercury.... do you even NEED to clean out the bores of the glass tubes?
Do any of you have suggestions. I know that per the post, above, I am NOT the only person experiencing these "bubbles" / gaps in the mercury columns. I have to wonder HOW, with mercury about 15 times more dense than gasoline... HOW it could happily sit ABOVE the gap or bubble? It seems so implausible to me.
I want to save $ (and I like the theoretical accuracy of the Hg columns) - but I know that with bubbles in the columns, they are NOT accurate.
TIA!
I had the same problem with my mercury sticks. I blew in the hose to push all of the mercury out of the affected tube into the reservoir. When you stop blowing the mercury reenters the tube sans bubbles. Might take a couple tries. Do not suck on the hose! YMMV.
Larry
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Thank you, LarryS.
I will give it a try...
Cheers!
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I emptied and refilled mine. Worked for a while then got bubbles again. I got tired of fussing with it. Not worth the trouble. In the time I spent trying to get it to work right I could have made twenty beer bottle balancers and ridden half way across the country. On top of all that, it's mercury - the stuff evaporates, silly as that seems, so you have to ensure it's closed to atmosphere when you're done using it. It's a dangerous substance so that that into consideration. I know, an electronic balancer costs some bucks, but here we've got the perfect guzzi tool for an incredibly low price (guzzi content), so it should be a no-brainer tossing the mercury stix and moving up to the bbb (beer bottle balancer).
I know I would if I was in your position.
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Just found the solution to the bubble issue... if a person did want to keep the mercury manometer based tool: http://gpzweb.s3-website-us-east-1.amazonaws.com/ManometerNotes/ManometerNotes.html It seems to me that the mercury sticks give an immediate indication of which carb (slide) starts to open first... that the beer bottle manometer does not. In any case, ideally, the beer bottle device and the mercury manometer could both be used, i.e. simultaneously.
The trick is to collapse the Hg columns using a syringe each time you use the device... while it is hooked up and the engine is running. A simple pull on the syringe (applied to the vent tube) does the trick for each tuning session.
See the link above, plus the two photos
(https://i.ibb.co/YXGf38v/Syringe-1.jpg) (https://ibb.co/YXGf38v)
(https://i.ibb.co/Hphxwzk/Syringe-2.jpg) (https://ibb.co/Hphxwzk)
provided (from the article).
The device in the cited article is, in fact, a Motion Pro manometer...
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And, amazingly, here is a source for mercury if you need it: https://www.saber-cycle.com/store/product1003.html
AMAZING that they still have this.
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And, amazingly, here is a source for mercury if you need it: https://www.saber-cycle.com/store/product1003.html
AMAZING that they still have this.
It's quite expensive, 70 grams would be 5 cc (maximum quantity they can post), definitely worth it if you were just a little shy
I worked for a firm that spent millions of dollars trying to rid the town of Squamish of mercury spilt from an old Chlorate plant, it was used as one electrode in an electrochemical cell, we ran a plant for about 5 years to remove a few Kg from the groundwater
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Another argument for using Oil rather than Mercury.
I use a "U" tube manometer about 30 inches high half filled with engine Oil, I knocked this up for less than $10 many years ago.
I can really only measure about 20 inches of difference before I'm afraid of sucking the oil into the engine, this is plenty for the purpose of aligning the carbs.
If I was to use mercury, what height of column would be equivalent to my 30" "U" tube
Using my working range of 20" differential.
20 / 13.6 (SG of mercury) = 1.4" So I only need a mercury "U" tube that will measure 1.4" to replace my Oil column
But wait, my oil has an SG of ~ 0.8
(20 / 13.6) x 0.8 = 1.17" Hg so I really only need a mercury column just over an inch tall to balance my carbs.
However I would never be able to keep the mercury contained, if say one of the hoses were to drop off, the imbalance of pressure would blow the mercury into the engine quicker than you could blink.
This is the reason they make the mercury columns tall enough to withstand the strongest vacuum they can possibly see, full manifold Vacuum, As they measure gauge pressure rather than differential pressure they need to be about 30" tall. They also add restrictors in the hoses to damp the action.
Why do we want to measure Gauge pressure? mainly for ease of use with a multi cylinder engine, for a 2 cylinder we just need to know the difference (differential pressure). To measure differential pressure you don't need such a wide range.
My 30" Oil filled "U" tube will not withstand a hose dropping of either but because of the oil viscosity (damping) I don't need restrictors, I have plenty of time to shut down the engine if something goes amiss.
I like the idea of the beer bottle balance tool, I think it is nice and compact, mounted on a block of wood its self standing whereas my column needs to lean against the bike and it's only visible from one direction.
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And, amazingly, here is a source for mercury if you need it: https://www.saber-cycle.com/store/product1003.html
AMAZING that they still have this.
I have mercury for life. My RN brother-in-law gave me a bottle of medical mercury many moons ago. Seems that it was used to weight some probe that gets slid down ones esophagus into the stomach. Once its been used, it supposed to be disposed of. My mercury sticks have needed to be topped off once in the twenty plus years I've owned them.
Larry