Topic: Can I use water (or other ideas) to test my carbs before remounting to the bike?

[TwoTired]

When a drop of water gets in a jet it usually stays in the jet.

By what physics principle to you refer?    Is the consumption of pharmaceuticals involved in it's instantiation?
I suppose if the temperature is 32F or below the jet can be blocked.  But, most of us call that ice, rather than water.

Some water CAN go through an engine (carbs) but after that happens, then the gas will not go through the water. Then it quits running.

As long as there is suction on the jet, it will draw any liquid through it, at a rate determined by it's viscosity.  There is very little difference in viscosity between gasoline and water.

I suggest you test your own theory with a common drinking straw.  Tape a jet onto its end and dunk it into room temp. water and suck.  If your premise is true, you'll get no water to pass through the jet.  Then with the same wetted jet, dip it in some gas and suck.

Do report your test trial results, when you are finished spitting and choking.

[Bailgang]

Do report your test trial results, when you are finished spitting and choking.

+1 You have a brutal sense of humor TT. 

[lucky]

Thanks Lucky for the help.  I have a float gauge and used this to set them.  So when you say "the book says", do you mean the BIBLE?!?  I don't remember anything in there about motorcycles, but I'm not one to go to church either.  I have a haynes manual and a shop manual.  The only reference I have found for the float hight on a stock 1977-1978 CB750 (A,F, and K) is 14.5 mm.  If someone can cite where it is in the service manual that would be great.  Did you know that these floats on these years of CB750 are .......NOT round?!?!  This makes it even more of a mystery as to how to set them when taking the reading.  There seems to not be a specific way to place the carbs when setting the 14.5mm.  Some posts on this forum say on their back, some say at 90 degrees some say 45 degrees.  I even included a ASCII diagram picture and got an answer that was helpful, but was still hard to figure out (there are 2 directions to put a rack of carbs in from the answer and they would both be at a 45 degree angle so which one do I pick).

Why the heck don't any of the "Books" have a picture of how to do this procedure?  Is this a honda secret or do you have to be born into a motorcycle family and have it passed down from father to son.  The secrete of where the set the carb body when setting the float height. 

So I'll watch out for the honda mechanic who tells me "I think I set the floats right" and demand my money back, but here you are comparing my skill set to a honda mechanic.  I am not a honda mechanic, just some dude with a bike trying to get it on the street so hence the quote I think I set the floats right.

If I have not seemed sincere, I am and I want to thank you and to everyone who is offering their advice and time to respond.  I know what you do is free and I appreciate your insight and have a lot of things to try to get my bike on the road again.

-S

Just one drop of water in the carbs will cause them to not work. especially if that drop of water gets stuck in the idle jet.


You "think" you got the float height right?
You need to go do it again, and use a measuring device like the book says FIRST.

No wonder it leaks.


IF you took your bike to a professional  Honda mechanic and he said, "I think the floats are right"

You better get your money back.

The Clymer's manual does show a photo of the measuring of float height.
The 1977-78 has a very interesting feature.
The floats are flat and when they are the correctly adjusted height  the bottom of the float comes right to the same level as the idle jet!!! Just do not push on them to make that happen. Only on the 77-78 CB750.
Photo:

[lucky]

Just one drop of water in the carbs will cause them to not work. especially if that drop of water gets stuck in the idle jet.


You "think" you got the float height right?
You need to go do it again, and use a measuring device like the book says FIRST.

No wonder it leaks.


IF you took your bike to a professional  Honda mechanic and he said, "I think the floats are right"

You better get your money back.

What size is this drop? I'm glad my carbs don't know about this or they would never work with the gas around here. Some how my bike will keep running and pretty damn good I might add. I don't know where you come up with this crap? Do you ever read some of the stuff you spout out?

I always read what I wrote before posting.
If you do not like what I say just move on the another post.


I have worked on bikes that were running very poorly and would not idle.
When I removed the idle jet I could see light through the jet but it was cloudy and when I blew the jet out onto a sheet of paper it was not gasoline it was water, and it just soaked into the paper. The water by capillary action/surface tension, can hang up in the hole and the gas cannot get sucked through. Water and gas will not mix.
By putting Seafoam into your gas, the water/moisture in the gas is held in suspension in the gas and dispersed into the gas instead of collecting in the bottom of the gas tank and getting sucked into the engine. Ethanol absorbs water.

I have seen cars that would not run and a single drop of water was between the push on 12 volt connector and the body of the distributor and the car would not run.  All it takes is for the gap to be small enough and even a 50 mph wind will not blow out that drop of water.

[TwoTired]

If you do not like what I say just move on the another post.

What, and let you pollute an otherwise useful forum with fantasy fiction, and outright lies?
If you wish to present fiction unopposed, then stick to the open forum.

I'm of the opinion that a technical forum should strive to be technically sound.  Not just a collection of false myths and made up yarns by those suffering from dementia.

If you continue to lie to unsuspecting tech forum readers.  I will continue to point out the glaring lies you espouse.  The physical world behaves according to its own laws.  Humans (and the machines they create) can't change those laws no matter what they believe.   One either learns about the laws to fit comfortably within them, or suffer the tribulations that ignorance, denial, and misunderstanding bring.   

I now understand why teaching credentials have some value.

[lucky]

Thanks everyone for the help.

KJ790 - So the black line (one at the bottom of each bowl) is where the fuel is leaking from.  This I think is where the fuel runs when there is too much (overfill problem) within the bowl.  The drain screws are not leaking that I can tell.  The leaking seems to happen when I come to a stop.  I guess it could be leaking all the time while I was riding, but I suspect that it wasn't as when I started it, there wasn't any leaking, but I'll recheck the drain screws.  You saw that my carbs are the ones that came with the '77-78 CB750's?  They are stock.

oldschoolcarbs - So on these carbs it lists the float height in a haynes manual as 14.5mm.  Do you put the gauge at the middle of the float, toward the tip of the float or back by the pivot point?  Do you turn the bank of carbs on their side (i.e. starting from the normal position on the bike if you could run a rod from the head light between carb #2 and #3 to the tail light and then turn the bank of carbs on this line 90 degrees in their plane so now instead of the plane being at 9 to 3 o'clock, it is now 12 - 6 o' clock. C=carburetor body

From this                C1---C2-+-C3---C4
to

This

C1
|
|
|
C2
|
+
|
C3
|
|
|
C4

Or do you set the floats with the carbs upside down?

Steve-o - i'll try the tapping trick before pulling it all apart.  Thanks

Thanks again everyone

-S

You really would want to hold the carbs on a 45 degree angle, not 90 degrees. The needles will stick and not fall to the float tang keeping them at a 90. You can even hang a carb (if separated) or the whole rack in their natural up/down position to check the height. You almost need to be a monkey to do this , but you will get it. Just make sure your needles aren't hanging up whilst checking the height. And you really want to use the float tool against the gasket base and check the tallest point of the float circle. If your pretty confident you did the float adjustment right, and don't want to pull the rack, do the clear tube fuel height check method. It's covered how to do it in several threads here. All you need is about 6" of clear fuel line, and the plastic ball point pen end to do it. Fit the fuel line onto the end of the pen end, and thread the plastic pen end into the carb drain hole. Hold the fuel line up 90 degrees, without kinking it and turn on the fuel. You will "see" where the actual fuel height is.

Even if you measure the float level with the carb upside down the float will not depress the spring pin in the float needle because the float is much lighter weight than the earlier brass floats.
Try it and you will see. If you still do not like that, just hold the carb on it side to to the measuring.


Or you use that method shown in my photo showing the bottom of the float even with the bottom if the idle jet.

[TwoTired]

Even if you measure the float level with the carb upside down the float will not depress the spring pin in the float needle because the float is much lighter weight than the earlier brass floats.

This may be true for aftermarket float needles with a stronger springs behind the pin (not a recommended part).  But, the original needles will compress the pin with the weight of the float, making a false height setting.

Measure the float heights with the carbs on their side, to take to gravity affects out of the measurement process.  Just make sure the needle is fully in the seat when checking the float tang contact with the valve's pin.

However, if you ARE using float valve needles with stronger spring pins, a book value mechanical height adjustment will not result in correct fuel level.  You will have to use the clear tube method to find what mechanical setting will result in correct fuel level inside the carb bowls.

[lucky]

Even if you measure the float level with the carb upside down the float will not depress the spring pin in the float needle because the float is much lighter weight than the earlier brass floats.

This may be true for aftermarket float needles with a stronger springs behind the pin (not a recommended part).  But, the original needles will compress the pin with the weight of the float, making a false height setting.

Measure the float heights with the carbs on their side, to take to gravity affects out of the measurement process.  Just make sure the needle is fully in the seat when checking the float tang contact with the valve's pin.

However, if you ARE using float valve needles with stronger spring pins, a book value mechanical height adjustment will not result in correct fuel level.  You will have to use the clear tube method to find what mechanical setting will result in correct fuel level inside the carb bowls.

Who buys aftermarket float needles and tests the amount of spring pressure the float needles have?  And even if you had the instruments to test them,
 how would you know what the spring tension of the original float needles were 40 years ago?

[TwoTired]

Who buys aftermarket float needles and tests the amount of spring pressure the float needles have? 

Hondaman.  And he reported this in a prior posting.

And even if you had the instruments to test them, how would you know what the spring tension of the original float needles were 40 years ago?

Because the fuel level was wrong in the carb bowls when the needles with stiffer springs were used and set to book value heights.

[lucky]

Who buys aftermarket float needles and tests the amount of spring pressure the float needles have? 

Hondaman.  And he reported this in a prior posting.

And even if you had the instruments to test them, how would you know what the spring tension of the original float needles were 40 years ago?

Because the fuel level was wrong in the carb bowls when the needles with stiffer springs were used and set to book value heights.

OK..I did not know anyone had done that type of testing.
 Sounds reasonable .

But I have always used aftermarket needles and installed them and never had any problems.
I wonder how much the difference was? Which brand , is that in HondaMans book?

Gordon, Steve-O , Oldschoolcarbs, and myself do not think putting water in a carb for testing is a good idea.

It is interesting to me that you pay attention to such small details like the spring pressure of a aftermarket float needle but would still think its ok to test with water in the carb instead of gasoline.

[mono]

Also could I use water instead of gas so I don't have to keep losing brain cells doing this?  Could I use another type of fluid (not sure what I would use)

good idea in theory, although i agree with the others' opinions about it being a bad idea in practice.

unfortunately this is one of those "no easy way around it" parts of maintenance, although the upside is that the more gas you huff, the easier it is to get your carbs working for some reason.

[Deltarider]

I'm told (by a mechanic) that water actually can 'hang on' a long time in jets and so cause irregularities (misses?). I don't know the theory behind it though.
The stuff that we call petroleum (I believe you call it kerosene) is quite harmless. In the old days I've seen people use it in their hair (vanity? lice?)

[TwoTired]

But I have always used aftermarket needles and installed them and never had any problems.
I wonder how much the difference was? Which brand , is that in HondaMans book?

1-1.5 mm, Keyster, if I recall correctly. As I said, it was in a prior post in this forum.  I tend to notice real technical information posted here among the frequent opinion, myth, and unsupported theory.  It was 1 or 2 years ago,  I can't find the post right now. 
But there is this:
http://forums.sohc4.net/index.php?topic=105027.msg1400880#msg1400880

Gordon, Steve-O , Oldschoolcarbs, and myself do not think putting water in a carb for testing is a good idea.

It is interesting to me that you pay attention to such small details like the spring pressure of a aftermarket float needle but would still think its ok to test with water in the carb instead of gasoline.

I never said testing with water is a good idea.  In fact, I believe it is a bad idea.

My argument is with your statement that water can't fit through the jets, which is preposterous, as it has been doing just that since engines began to use gasoline.

Our gas tanks are vented to atmosphere, and humidity condenses water on the inside of the tanks during each cool down cycle.  The water dribbles down to the bottom of the tank where the fuel outlet is, then flows to the carbs.  The carbs draw this through the jets and pump it out the exhaust.  When ethanol was forced upon us, that condensate is absorbed by the alcohol (until the alcohol is saturated).  Ethanol has it's own set of problems.  The point is, water WILL fit through fuel jets, readily.  That is simply a principle of physics.

[lucky]

OK ...I agree with most of what you say.
But i did not say"water can't fit through the jets, "

I was saying water or gas with water in it can get hung up in a jet.
That has happened to my own bike in the winter time here in California.
I live right on the coast.
I just take the idle jets out clean them and then the bike will run properly.
I started using Seafoam and I seem to have less of a problem.

[TwoTired]

Just one drop of water in the carbs will cause them to not work. especially if that drop of water gets stuck in the idle jet.

But i did not say"water can't fit through the jets, "

I was saying water or gas with water in it can get hung up in a jet.

I don't see any physical explanation for that.  Why is it that it can ignore the engine suction?
The old gas was a lubricant, too. So, it tends to disassociate water from metal surfaces.  Meaning it will creep under the water to coat metal surfaces unless detergents are added.  Gas with ethanol will absorb water it contacts until it becomes saturated. 
I picked up a 77 CB750 that sat outside abandoned though 15 rainy winters here in California.  The bottom half of the gas tank collected the condensation water, but it didn't rust out at the bottom.  It rusted the top of the tank where gas was not in contact with the metal.  This why it is usually best to store with a full tank.  Ethanol kinda changed that.

That has happened to my own bike in the winter time here in California.

I think you've misinterpreted what is happening.

I live right on the coast.

This would seem to implicate boat motors as well.  They suck water in from vented systems routinely.
Anyway, I live ~5 miles from SF bay.  On shore wind currents are routine nearly every day unless it is raining  We don't actually get salt spray here, though.  But, things do rust outside.

[lucky]

Just one drop of water in the carbs will cause them to not work. especially if that drop of water gets stuck in the idle jet.

But i did not say"water can't fit through the jets, "

I was saying water or gas with water in it can get hung up in a jet.

I don't see any physical explanation for that.  Why is it that it can ignore the engine suction?
The old gas was a lubricant, too. So, it tends to disassociate water from metal surfaces.  Meaning it will creep under the water to coat metal surfaces unless detergents are added.  Gas with ethanol will absorb water it contacts until it becomes saturated. 
I picked up a 77 CB750 that sat outside abandoned though 15 rainy winters here in California.  The bottom half of the gas tank collected the condensation water, but it didn't rust out at the bottom.  It rusted the top of the tank where gas was not in contact with the metal.  This why it is usually best to store with a full tank.  Ethanol kinda changed that.

That has happened to my own bike in the winter time here in California.

I think you've misinterpreted what is happening.

I live right on the coast.

This would seem to implicate boat motors as well.  They suck water in from vented systems routinely.
Anyway, I live ~5 miles from SF bay.  On shore wind currents are routine nearly every day unless it is raining  We don't actually get salt spray here, though.  But, things do rust outside.

OK..I will try to give you the explanation why the jet will not let the water through so it can then get gas.

If the engine has been sitting and that water laden gas gets into the fuel system the water laden gas or drop of water will not get sucked through because the engine will not start. The engine has to start so the pistons can make the suction/vacuum.

Some people even run batteries dead trying to get the engine to start to no avail.
Then they finally have to take the carb off and clean out the junk in the float bowl and jets to finally get it to run.

When I say"junk" I mean fuel with water in it, or just the water.

[TwoTired]

If the engine has been sitting and that water laden gas gets into the fuel system the water laden gas or drop of water will not get sucked through because the engine will not start. The engine has to start so the pistons can make the suction/vacuum.

The engine makes suction on each intake stroke whether the mixture is igniting or not.  What do you think provides the air fuel mixture for the engine start?
The suction is what makes the jets flow any liquid available.  If the only liquid available is water, you don't get fire.

Water in the gas in not a new issue.  Yes, if you have enough volume of water, the battery will run down before it can be sucked through the engine to finally get ignitable fuel.  That doesn't mean the jets have to be cleaned manually, although removing the water will hasten the starting process.

Part of the aviation preflight is to sample the fuel drains/sump for water.  Water does occur.  You just have to keep it minimized so that the engine won't quit for so long that you can't relight the motor.  You don't have to rebuild the carburetor when water is found.  You do have to do a run up to verify the engine won't sputter during take off.

[Bailgang]

If the engine has been sitting and that water laden gas gets into the fuel system the water laden gas or drop of water will not get sucked through because the engine will not start. The engine has to start so the pistons can make the suction/vacuum.

Can we agree that water doesn't burn/ignite? If so than wouldn't it be feasible that the reason an engine that has gas laden with water wont start is because it IS sucking in that water and therefore not igniting? That engine could be sucking harder than Linda Lovelace but that engine still wont fire if all it's sucking in is water or fuel that has too much water in it to ignite. You have heard of a fuel additive that's been around for ages called Heet haven't you? The whole purpose of the stuff is that it's a flammable liquid (lots of alcohol I think) that's able to mix with that water in a gas tank formed from condensation making it able to ignite. It used to be real popular in colder climates and might still be.

[Bob Wessner]

That engine could be sucking harder than Linda Lovelace but ..

 

[Vinhead1957]

Water does not compress if you run water through the engine trying to start it in liquid form it will blow your head gasket!

Mist water is used to clear carbon deposits in dragsters. Old cars used to have a vacuum line to a bottle of water for this purpose also

[Bailgang]

Water does not compress if you run water through the engine trying to start it in liquid form it will blow your head gasket!

Mist water is used to clear carbon deposits in dragsters. Old cars used to have a vacuum line to a bottle of water for this purpose also

+1 to what you said but you're obviously missing the point so please don't be taking this topic off on a wild tangent. Of course too much water can cause a cyl to hydraulic (no argument there from me) and in a worst case scenario is actually capable of doing a lot more damage than just blowing a head gasket but that was never the point. The point that TT has been turning blue trying to explain to lucky about is that water laden fuel can get sucked through the jets in the first place.

[mono]

[/quote]

Can we agree that water doesn't burn/ignite?
[/quote]

WHAT THE HELL ARE YOU TALKING ABOUT, BAILGANG !! ANYTHING WILL BURN IF YOU GET IT HOT ENOUGH!!!!  GOD... ITS SIMPLE SCIENCE !!

    

Blaaahrrhghghghghghhg

[Bailgang]

Can we agree that water doesn't burn/ignite?
[/quote]

WHAT THE HELL ARE YOU TALKING ABOUT, BAILGANG !! ANYTHING WILL BURN IF YOU GET IT HOT ENOUGH!!!!  GOD... ITS SIMPLE SCIENCE !!

    

Blaaahrrhghghghghghhg
[/quote]

Now don't be getting technical on me.  If we're fortunate this thread will just curl up and die.

[icecoast]

you guys are crazy for keeping this pointless argument going.

[Deltarider]

you guys are crazy for keeping this pointless argument

Now don't you start an argument, youngman!
https://www.youtube.com/watch?v=kQFKtI6gn9Y