DIY carb sync tool

[Ken Talbot]

Originally posted by trbig
OK.. lol.. Re-reading that.. I am agreeing with the statement. The size of the tube has nothing to do with the amount of pressure exerted on the liquid.. but would have to do with how high the fluid was drawn up the column.

Hmm, and I guess with a bit more reflection on high school science class, it is all about the amount of pressure being exerted on the reservoir (i.e. one atmosphere) that is pushing the fluid up the tube when there is less pressure at the top of the tube.

Enough for now - my head's starting to hurt, much like it did in high school...

[pggg]

Originally posted by 81xsproject
Maybe I had a junky vac gauge, but I am going to have to disagree. I did a vac synch with my gauge set-up and then connected up my tubing syncher and found there was a substantial amount of adjustment left to be done. Also noted was a significant improvement in the smoothness of the idle from the gauges to the tubing. I have since thrown my gauge in the trash.

81, I'm picking you had the gauge undamped or else the gauge was junk, but balancing 4 carbs with one gauge only is tricky to get right, mro's sussed it, these 4 gauge sort are real easy to use if finding it difficult

[Hired_Goon]

Originally posted by Ken Talbot


I That's the beauty of these systems that have carbs connected to each end of a tube of fluid, so they're pulling against each other, not against gravity.

You nailed it right there Ken. Equalising each carb against the others.


I'm afraid all this talk about vacuum vs gravity is rather irrelevant as there is no way I can get my bike high enough off the ground to use a gravity system in an open reservoir using 3mm tubing.

Gravity is also irrelevant in a closed circuit.

Oh, and pgg, surely there must be an error with the instructions on those gauges. Surely they must be anti atmospheric guages as vacuum doesn't really exist.

But, I have used those and the only disadvantage I ind with them is it is possible to make them read what you want them to read just by screwing the restrictor in an extra half a turn on a single guage.

The other on with a fourwy and single gauge would be better as it uses the same restrictor for all four carbs.

[trbig]

I'm afraid all this talk about vacuum vs gravity is rather irrelevant as there is no way I can get my bike high enough off the ground to use a gravity system in an open reservoir using 3mm tubing.

????? You need the tubes off the ground going up, why on earth would you put a bike in the air? But yeah, if you're stuck on using 3mm tubing, it's probably not going to work for you.

You nailed it right there Ken. Equalising each carb against the others.

If this is the best way, why do none of the commercial units do it? I'm not trying to start any fights... I just don't understand the reasoning. I guess instead of talking about it, I need to just build one like I'm thinking and see how it turns out.

Tod

[manshack_one]

yeah, I'm just going to break down and build one like goon's. now, what ID do I need for those sync nipples on the boots? I can't wait anymore, having the bike in the garage waiting for a sync is killing me.

[pggg]

From HG - " Oh, and pgg, surely there must be an error with the instructions on those gauges. Surely they must be anti atmospheric guages as vacuum doesn't really exist.

But, I have used those and the only disadvantage I ind with them is it is possible to make them read what you want them to read just by screwing the restrictor in an extra half a turn on a single guage.

The other on with a fourwy and single gauge would be better as it uses the same restrictor for all four carbs."


HG, screwing in or out the dampers/restrictors doesn't change the vacuum reading, it just steadies the needle(s), the actual vacuum reading's still the same

[81xsproject]

manshack,
get automotive rubber vac hose for the ends of the tubes. The vinyl tubing will get very soft when warm and could allow for a leak. You will also want some kind of restriction to dampen the pulsing. The easiest way is to gets some hose connectors (that you need anyway to connect the vac hose to the vinyl tubing), fill them with JB weld, get an extremely small drill bit, and drill a hole through the JB Weld once it has cured.

[Trikerneil]

Atmospheric pressure will support a column of water approximately 32 feet high - no matter if the tube is 3mm or 300mm diameter.
Weight has nothing to do with it, it's all surface area and pressure.

Neil

[Hired_Goon]

Originally posted by trbig


????? You need the tubes off the ground going up, why on earth would you put a bike in the air? But yeah, if you're stuck on using 3mm tubing, it's probably not going to work for you.

Because the length of tube required for gravity to take affect over the amount of vacuum would be huge.

Originally posted by trbig





If this is the best way, why do none of the commercial units do it? I'm not trying to start any fights... I just don't understand the reasoning. I guess instead of talking about it, I need to just build one like I'm thinking and see how it turns out.

Tod

I don't claim it's the best, but it is accurate.

Noone would build a commercial unit as there are risks associated with it. Ie, it is possible to suck the contents of the tubes into the engine. No manufacturer will take that risk.

Besides, if they did I would sue for intelectual copyright infringement.

It is a cheap homemade device to do a simple job that would cost over $100 if buying a commercial unit.


pggg, I watched a guy use a set of 4 guages and he had one restrictor almost fully screwed in. This did affect the guage a little when I opened it up again. But yes, If you are just adjusting till the flicker stops then it won't make any difference.
This guy was just inexperienced using them.

[Hired_Goon]

Originally posted by 81xsproject
manshack,
get automotive rubber vac hose for the ends of the tubes. The vinyl tubing will get very soft when warm and could allow for a leak. You will also want some kind of restriction to dampen the pulsing. The easiest way is to gets some hose connectors (that you need anyway to connect the vac hose to the vinyl tubing), fill them with JB weld, get an extremely small drill bit, and drill a hole through the JB Weld once it has cured.

Or, better still, take the tube from the nozzle of your carb cleaner or WD40 tins and JB weld them into connectors.

And a big yes to auto rubber hose for the ends. It does get hot around there.

[trbig]

Atmospheric pressure will support a column of water approximately 32 feet high - no matter if the tube is 3mm or 300mm diameter. Weight has nothing to do with it, it's all surface area and pressure.

Ummmm... HUH?!? Atmospheric pressure is 14.7 pounds. If weight has nothing to do with it, then why does everyone build water towers to have water pressure?? Why does it take huge pumps to get the water to the top? Maybe I don't understand what you are saying. How is 15 pounds going to hold up thousands of pounds? If I stick my straw into a column of fluid (Coke), why won't the atmosphere push that fluid up my straw to my mouth for me?

Tod

[trbig]

Because the length of tube required for gravity to take affect over the amount of vacuum would be huge.

In a 3mm tube, I agree.. that's why I said it wouldn't work. But the few pounds of vacuum applied to the line by the carb will only draw a few pounds of fluid up the line. That's why I said to use a bigger diameter hose. I said 1/2 inch, but it may take more than that to be able to draw the equal amount of weight of water up a tube. Surface area and prssures be damned... 5 pounds of pressure is only going to pick up 5 pounds of water... no matter the size of the diameter of the tube.

Tod

[Ken Talbot]

Originally posted by trbig
Surface area and prssures be damned... 5 pounds of pressure is only going to pick up 5 pounds of water... no matter the size of the diameter of the tube.

Tod

Ah, but there's the rub, it is not just 5 pounds of pressure. It could be 5 pounds total, if you have 5 pounds per square inch over one square inch. That would be a fairly good size tube. If you have 5 pounds per square inch over only, let's say 1/10 of a square inch, which is a much smaller tube, you're only going to get a total lift of half a pound. See where this is going?

[fredintoon]

pressure is independent of surface area

Dammit guys, how can you all be computer literate and still be so ignorant of basic science?
Google pascal's vases and if you can't understand the words, look at the picture.

[Trikerneil]

Spot on Fredintoon - I was wondering how I was going to explain it in words.
A picture tells a thousand words, so that's saved me some typing

Neil