Puff of white smoke and milkshake in my oil.

[Popsnana19655]

I have watched most of these videos so far. Remind me of shop class. Teacher was cool. Last class of the day.  Told us work on what ever you want. Just don't cut off your hands or get caught. And put the dam tools back where got them. 

[Popsnana19655]

Good then.  I'm about ready to pull it. Just got the drive shaft left to do. Do I need to pull the rear wheel. Or disconnect at the york there. Stopped there got attached by my twin 2yo nephews . They're helping with taking parts and tools then running. LOL looking up drive shaft now. 

[saddlebum]

On 10/17/2020 at 3:17 PM, Patch said:

First thing I'd like to comment on is the ease of reading in this new format...

So a couple of thoughts to share and think on when coming up with the repairs:

The back flow from jugs to carb blows is a bit hard to understand for me perhaps I am just reading it wrong.

But the only way to the carbs is past the valve seats under the compression stroke. That said with blown head gaskets one would think that thee path of least resistance would be other than the seats. That said then likely the valve seats and valves would need facing.

We have seen these bikes hit way too high compression readings, as was the surprise with Luv's bike some years back, I was amazed that the head gaskets weren't leaking or other issues apart from the per detonation it was experiencing. Bares asking what the compression number are on the jugs not yet leaking.

Another concern I would have: Are the rings fractured or broken? This would also apply to ring landings. The reason being is that the bike was run on the good jugs which obviously place an compressible fluid between the TDC and chambers; that has to of had effect unless the fluid was compressed out thru and out to atmosphere. This can mean a whole host of potential issues which include journals rods wrist pins and bosses.

Should you choose to rebuild I would suggest you expect to do both sides, then you will want to measure off the decks the TDC's to ensure no bottom end damage!

If they show or prove spec then a washing of the jug walls will be in order to remove the varnishing cause over time and the coolant.

While there check heads...

Or speak to Casey about the unit he has, maybe it would be a a less expensive fixerupper

just some thoughts

Consider if the bike was just sitting with the coolant pressure tester attached and the defective cylinder was sitting on its intake stroke with valve open then as the cylinder filled with coolant it definitely would back up into the carb as @cowpucsuggested. Something I have come across on other engines in the past and find myself somewhat dumbfounded that it did not occur to me in this case. For some reason when he mention coolant appearing to come from the frame, My minds eye was  fixated on the front of the bike.

[saddlebum]

On 10/23/2020 at 12:00 AM, Popsnana19655 said:

Good then.  I'm about ready to pull it. Just got the drive shaft left to do. Do I need to pull the rear wheel. Or disconnect at the york there. Stopped there got attached by my twin 2yo nephews . They're helping with taking parts and tools then running. LOL looking up drive shaft now. 

Nothing like starting apprentices off before they develop bad habits.

[Patch]

6 hours ago, saddlebum said:

Consider if the bike was just sitting with the coolant pressure tester attached and the defective cylinder was sitting on its intake stroke with valve open then as the cylinder filled with coolant it definitely would back up into the carb as @cowpucsuggested. Something I have come across on other engines in the past and find myself somewhat dumbfounded that it did not occur to me in this case. For some reason when he mention coolant appearing to come from the frame, My minds eye was  fixated on the front of the bike.

Yes I get that but, I can't see how it would make its way to the bowls? Or is that my misunderstanding?

[saddlebum]

On 10/25/2020 at 2:04 PM, Patch said:

Yes I get that but, I can't see how it would make its way to the bowls? Or is that my misunderstanding?

There are jets and port passages, 5 in total, including the cold start and coast enrichment valves, plus three air vents at the top edge of the venturi that lead to the fuel bowl were coolant can back up into the fuel bowl once coolant flooding back from the faulty cylinder floods the venturi.

Edited October 28, 2020 by saddlebum

[Patch]

3 hours ago, saddlebum said:

There are jets and port passages, 5 in total, including the cold start and coast enrichment valves, plus three air vents at the top edge of the venturi that lead to the fuel bowl were coolant can back up into the fuel bowl once coolant flooding back from the faulty cylinder floods the venturi.

HMM no Ben not buying that.

[cowpuc]

5 hours ago, saddlebum said:

There are jets and port passages, 5 in total, including the cold start and coast enrichment valves, plus three air vents at the top edge of the venturi that lead to the fuel bowl were coolant can back up into the fuel bowl once coolant flooding back from the faulty cylinder floods the venturi.

and,, any time I have saw gas and water mixed, the water always seemed to end up at the bottom of the mix. So the coolant goes up the intake, fills the venturi, displaces the fuel in the vents/jets/emulsion tube and settles into the bottom of the bowl until it fills the bowl to the brim cause it is not being controlled by the float valve and ends up going out of the overflow tubes.. 

[Patch]

1 hour ago, cowpuc said:

and,, any time I have saw gas and water mixed, the water always seemed to end up at the bottom of the mix. So the coolant goes up the intake, fills the venturi, displaces the fuel in the vents/jets/emulsion tube and settles into the bottom of the bowl until it fills the bowl to the brim cause it is not being controlled by the float valve and ends up going out of the overflow tubes.. 

Well Puc its about time you come out from the closet!

Somewhere I thought I got confused by your posting that started this knockdowndragemout conversation, but nope.

Now if you said that the FRAME was water filled and that the vent tubes were somehow placed inside the flooded frame, then yes which is what I thought you were leading to.

Water has roughly 1/3 more density then gasoline. Bear with me, now if the venting cycle had been reversed so that the tubes were then siphoning - the density would have a possessive/greater effect over the float; lets remember that the float is levered .

But in the case as presented we are ignoring the obvious: (picking numbers here) 11 fading pounds of manual & intermittent pump pressure at the radiator, not one but 2 fluids are involved, both a compressible and noncopressisble. The noncopressisble will have a direct effect on the fleeding pressure at the rad neck.

Lets continue: the piston on the intake stroke is somewhere between TDC & DTC, this means greater volume, and, the intake valve is open to atmosphere so how may I ask that the cause of applied pressure at the rad neck has anything to do with lifting the fluids into and up? There cannot be a pressure under the given scenario.

Furthermore Ladies and Gentlemen should the pressure exist to move the fluid past the intake valve then we must consider Bernoulli principle as well as Venturi because at this point the throttle is closed, therefore bringing both rules into play. 

I beg your attention now be turned to chapter 5 p.2 just below the idle set position of the throttle plate. (unless it thought that the long path of resistance to the diaphragm is consequential?) we now turn our attention to the enricher valve, look up way up said the friendly giant, assuming the port is open (?) how would a fluid such as water or antifreeze make its way up then back down to the bowl with atmosphere being equal on both sides?

Is there another potential driving force? Well you could argue gravity which would be equal to the weight of the fluid above each potential infiltration point which will deprecate the higher the fluid measure is...

I Sirs, rest my case 

and my Henglish

Edited October 28, 2020 by Patch

[Sylvester]

Since my dogs don't fight I am staying out of this post. 😎

[Marcarl]

I think you guys are all fishing, but I'm not sure for what,,,, theory I think.

[Marcarl]

17 minutes ago, Marcarl said:

I think you guys are all fishing, but I'm not sure for what,,,, theory I think.

Not something I often do, but I read through the whole thread, even Puc's diatribe and Patch's redirections. Me thinks that it would make a whole lot of sense to scarp that engine and install another. It is never a good thing to get the sugary stuff into the internal mechanicals of such a fine tuned machine. I would be skeptical of having more issues down the road, unless every little item were super cleaned and double checked for wear, which might or might not have happened previously.

[Patch]

1 hour ago, Marcarl said:

Not something I often do, but I read through the whole thread,  SINCE WHEN   (fork put my blue back eh)

even Puc's diatribe    Really I read it twice and ended up on the same stump (:

and Patch's redirections. Me thinks that it would make a whole lot of sense to scarp that engine and install another. It is never a good thing to get the sugary stuff into the internal mechanicals of such a fine tuned machine. I would be skeptical of having more issues down the road, unless every little item were super cleaned and double checked for wear, which might or might not have happened previously.

NOW NOW< THERE THERE Weewhickers lets see if @BIG TOM can offer you some OKness

Yaknow we just needs to chew some leather Weewhiskers - just kind of enjoying this new paint job to the forum is all. Yaknow they cut my meds in half well I did actually then left a message then shut the phone off... Been singing this song all day, here it is so join me in a clearer day, eh

Ya always is the designated driver now just chill and leave it to the taller brothers

 

[saddlebum]

6 hours ago, Patch said:

Well Puc its about time you come out from the closet!

Somewhere I thought I got confused by your posting that started this knockdowndragemout conversation, but nope.

Now if you said that the FRAME was water filled and that the vent tubes were somehow placed inside the flooded frame, then yes which is what I thought you were leading to.

Water has roughly 1/3 more density then gasoline. Bear with me, now if the venting cycle had been reversed so that the tubes were then siphoning - the density would have a possessive/greater effect over the float; lets remember that the float is levered .

But in the case as presented we are ignoring the obvious: (picking numbers here) 11 fading pounds of manual & intermittent pump pressure at the radiator, not one but 2 fluids are involved, both a compressible and noncopressisble. The noncopressisble will have a direct effect on the fleeding pressure at the rad neck.

Lets continue: the piston on the intake stroke is somewhere between TDC & DTC, this means greater volume, and, the intake valve is open to atmosphere so how may I ask that the cause of applied pressure at the rad neck has anything to do with lifting the fluids into and up? There cannot be a pressure under the given scenario.

Furthermore Ladies and Gentlemen should the pressure exist to move the fluid past the intake valve then we must consider Bernoulli principle as well as Venturi because at this point the throttle is closed, therefore bringing both rules into play. 

I beg your attention now be turned to chapter 5 p.2 just below the idle set position of the throttle plate. (unless it thought that the long path of resistance to the diaphragm is consequential?) we now turn our attention to the enricher valve, look up way up said the friendly giant, assuming the port is open (?) how would a fluid such as water or antifreeze make its way up then back down to the bowl with atmosphere being equal on both sides?

Is there another potential driving force? Well you could argue gravity which would be equal to the weight of the fluid above each potential infiltration point which will deprecate the higher the fluid measure is...

I Sirs, rest my case 

and my Henglish

All this theory sounds impressive but you are overlooking the simple points here

1) engine is not running and intake valve at some point of open position

2) rad is pressurized at 14 PSI ( that is to say 14 PSI above your atmospheric pressure) Using a pressure tester.

3) once piston fills with coolant it exits out the intake and trickles past rings into crankcase

4) connected to intake is the carb and as the coolant level rises it enters the carb venturi were it has access to 5 in total, including the cold start and coast enrichment valves, plus three air vents at the top edge of the venturi. 3 of the 5 jets are open orfices the enrichment valves sometimes stick open so that is only a possibilty but at the top of the venturi are vents leadin into the fuel bowl coolant can enter and fill the bowel through any or most of these. the bowel has a vent at the top to which a hose is connected which terminates just above the twin kick stand coolant enter the bowel purges the fuel and soon coolant appears to be leaking from the frame behind the engine.

 

Edited October 29, 2020 by saddlebum

[Patch]

1 hour ago, saddlebum said:

All this theory sounds impressive but you are overlooking the simple points here

1) engine is not running and intake valve at some point of open position

2) rad is pressurized at 14 PSI ( that is to say 14 PSI above your atmospheric pressure) Using a pressure tester.

3) once piston fills with coolant it exits out the intake and trickles past rings into crankcase

4) connected to intake is the carb and as the coolant level rises it enters the carb venturi were it has access to 5 in total, including the cold start and coast enrichment valves, plus three air vents at the top edge of the venturi. 3 of the 5 jets are open orfices the enrichment valves sometimes stick open so that is only a possibilty but at the top of the venturi are vents leadin into the fuel bowl coolant can enter and fill the bowel through any or most of these. the bowel has a vent at the top to which a hose is connected which terminates just above the twin kick stand coolant enter the bowel purges the fuel and soon coolant appears to be leaking from the frame behind the engine.

 

HAHA no, regardless of the hand pump pressure, the coolant is not going to enter the bowl. Lets overlook the fact that we know the coolant loop is open and that air is prescient in the open loop; once the 14 lbs reaches the intake valve it has to be at atmosphere.

The only real resistance is the Bernoulli principle plays due to the position of the throttle plate and, to accept that there is some pressure behind the plate then we must accept the Law of Venturi right after the plate and at the very small opening of the idle circuit which is then reduce again by the idle jet. So Venturi says a low pressure exist after the restriction caused(in this case) by the plate and, that velocity has to increase as a result. Those are the rules.  

So in your scenario there should be enough lift to raise the fluid up and over the top of the carburetor, then that would be the only patch of least resistance.

As you say the engine is not running therefore other than the suspect hand pump the fluid is static, the enricher valve is likely close and certainly the costing circuit has no reason to be open.

Does that make sense? I cannot stress enough that if the cylinder is open to the coolant leak and that the intake valve is open, there can be no build up of pressure: unless there exist 2 other means of pressure available to displace the fluid, one would be piston travel the other circulating pump.

Water in the bowls would be a result of water pumped from the tank or siphoned up thru the vents before the engine shut down. This suggests that the fluid in the blows is a result of the last running of the engine.

 

 

 

 

[Marcarl]

Hate to pick sides here @Patch, but I can see @saddlebumpoint and theory. Makes more sense to me, but then I mostly work under a maple.

[Patch]

3 hours ago, Marcarl said:

Hate to pick sides here @Patch, but I can see @saddlebumpoint and theory. Makes more sense to me, but then I mostly work under a maple.

It is OK to pick sides Carl

The best discussions do not always end in agreement but the exercise and efforts brought forward both in printable and theory serve the practical which in turn serves understanding and troubleshooting, my opinion.

But simply put the enricher and costing circuits are up high then ported and valved. If the valve is closed then that forms an air lock in the riser/port (s) that to say a plumber for example may describe that as a shock/knock arrestor, the air in the passage is trapped the fluid then compresses the air turning it into a spring. The same applies for the costing circuit, both are high on the carb body, both circuits have valves, the designs vary but, both are designed for a lesser dense fluid meaning if closed they will stop a denser fluid easily. 

As I see it there is no driving force for the fluid, in an open loop, we can not maintain pressure. As the crank is not rotating then again there is no driving force to lift or apply lift or raise the fluid head past equalization. The idle jet also designed for a light/less dense fluid, so without gravity/fluid weight from volume, or a force behind the fluid, I have trouble visualizing the required back flow forces thru that very small jet. The air porting also is jetted at the top of the carbs so again....

The path of least resistance in the absence of a force is up and out the top of the bore to atmosphere. The rules of velocity caused by a restriction/narrowing  (the throttle plate) creates a drop in positive pressure regardless of fluid meaning, we have to pick a force to displace the fluid, air pressure alone will pass thru the liquid/fluid because it is less dense; that's how I see this scenario 

What I think is the missing is a slide view as a result of a cracked cooling port that will as Ben says fill a chamber. That I agree with and think most of us have experienced, but that force will equalize after passing thru the cracked casting until, all fluids (including air) are displaced, for that scenario the fluid will continue to rise until the level of fluid diminishes, leaving only air pressure to pass thru, causing splash, again, once the fluid stop flowing the only so does the displacement.. 

[cowpuc]

4 hours ago, Marcarl said:

Hate to pick sides here @Patch, but I can see @saddlebumpoint and theory. Makes more sense to me, but then I mostly work under a maple.

Yep,, I dont always agree with Bum either but on this one I can see his logic.  Both these champs are absolute guru's but this time I think Bum's logic fits and/or makes it easier for my back yard brain to follow.  In my very limited experience, water is denser than gas so I got to agree with Patch on that point.. I am not so sure why the reluctance to see why the water/coolant would not naturally, without being forced by pressure even, seek its way into the low spot of the  bowl, filling it to the point it would flow out of the overflows as Bum has pointed out. Not picking side here,, just saying that Bens point/theory makes sense..  Hopefully @Popsnana19655 is still following this thread cause these winners are on to something IMHO..  

[Patch]

Thinking here while on hold.... I likely have 20ish CV carbs in the shop, heads, intakes... So what would be a fare setup for an experiment to demonstrate this one way or the other?

And can we agree at least that 15psi is not reverent if as in all cases the Carb is open at the top to atmosphere?

Let me know  

[cowpuc]

1 hour ago, Patch said:

Thinking here while on hold.... I likely have 20ish CV carbs in the shop, heads, intakes... So what would be a fare setup for an experiment to demonstrate this one way or the other?

And can we agree at least that 15psi is not reverent if as in all cases the Carb is open at the top to atmosphere?

Let me know  

I think @saddlebum and/or @Marcarl can defend their own selves on this one but I do not believe the water finding its way to the bottom of the bowl is dependent upon pressure above ambient or vacuum for that matter so yes,, I agree @Patch , the 15 psi thingy is totally not relevant IMHO.. From that I would suggest just taking a small clear jar, fill it 1/2 full of gas, then take some coolant or just water and drip some into it and watch what happens.  Once you notice the water collecting in the bottom take the jar and shake it,, after you do I have a gut feeling that the water will be gone as it mixes with the fuel BUT, if you let it sit the water will probably seperate and collect again at the bottom.  Now add more water and keep adding water, over a short time I theorize that you will end up with full jar of water and no fuel present. Now if you keep adding water it will over flow the jar, which is what I am thinking Bum has been suggesting  was the issue with Pops carb that ended up leaking water out of the overflow tube up on the frame that made it look like the frame was leaking coolant LOL..  If you are wondering if it would be possible for water to leak into the bowl thru the jets maybe you could take a piece of saran wrap. poke a few small holes in it to simulate the jets, put a rubber band around it so the saran wrap is held above the fuel in the jar, pour water across the saran wrap and see if the water will drip into the gas and if it does, keep watering it and see if it will fill the jar.  Now lets see what the real guru's think...

Edited October 29, 2020 by cowpuc

[Marcarl]

1 hour ago, Patch said:

Thinking here while on hold.... I likely have 20ish CV carbs in the shop, heads, intakes... So what would be a fare setup for an experiment to demonstrate this one way or the other?

And can we agree at least that 15psi is not reverent if as in all cases the Carb is open at the top to atmosphere?

Let me know  

Easy enough from my looking in. Grab a carb making sure  that it is install ready, so, no open ports, tape off the bottom (the part that goes into the boot or manifold), make sure it's sealed well, now slowly pour water down the throat and see where it comes out. The throat being the air intake part that is usually at the top. Now when the test is done, you could just turn it upside down to drain or you could punch a weeee little hole in the tape, and time how long that takes. Just a pin hole eh!?!  Wanta keep you busy for a bit.

[saddlebum]

20 hours ago, cowpuc said:

I think @saddlebum and/or @Marcarl can defend their own selves on this one but I do not believe the water finding its way to the bottom of the bowl is dependent upon pressure above ambient or vacuum for that matter so yes,, I agree @Patch , the 15 psi thingy is totally not relevant IMHO.. From that I would suggest just taking a small clear jar, fill it 1/2 full of gas, then take some coolant or just water and drip some into it and watch what happens.  Once you notice the water collecting in the bottom take the jar and shake it,, after you do I have a gut feeling that the water will be gone as it mixes with the fuel BUT, if you let it sit the water will probably seperate and collect again at the bottom.  Now add more water and keep adding water, over a short time I theorize that you will end up with full jar of water and no fuel present. Now if you keep adding water it will over flow the jar, which is what I am thinking Bum has been suggesting  was the issue with Pops carb that ended up leaking water out of the overflow tube up on the frame that made it look like the frame was leaking coolant LOL..  If you are wondering if it would be possible for water to leak into the bowl thru the jets maybe you could take a piece of saran wrap. poke a few small holes in it to simulate the jets, put a rubber band around it so the saran wrap is held above the fuel in the jar, pour water across the saran wrap and see if the water will drip into the gas and if it does, keep watering it and see if it will fill the jar.  Now lets see what the real guru's think...

@cowpuc I did not mean to imply that it was totally dependent on pressure. Pressurizing the cooling system simply speeds things up for Diagnostic purposes. For example park two identical bikes side by side with identical issues leave one to the combined forces of gravity and the specific gravity differences of the two fluids gas being lighter than water, and pressurize the cooling system of the other both will eventually end up with the same results just that the pressurized one will get there a lot faster. For the most part I was only trying to point out that there are physical paths that are available for the coolant to end up coming from the defective cylinder enter the carb float the gas out of the fuel bowl and eventually lead to actual water coming out of the over flow tubes. Not disputing that fact that if you put gas and water in a jar that the gas will rise to the top while the water will settle to the bottom as a matter of fact when I stated the water purging the gas out of the fuel bowl it was based on that exact gas and water in the jar principal. Same holds true for oil or any other petroleum .

As a matter of fact If you blend the oil and water together vigorously enough such as may occur in an engine were coolant finds its way into a crankcase they will mix hence that tasty looking mocha milkshake. leave the mixture in a jar and after a time you will actually watch the mixture separate, with the water  settling to the bottom and the oil floating to the top. When I worked for a tank truck outfit, we would occasionally get spills that got into the storm sewers which led into nearby rivers. We would build a floating  Dam which stopped the oil floating on top of the water and allow the clean water to flow past the underside of the Dam . We would then use big sucker trucks to suck the oil off the surface.

Edited October 30, 2020 by saddlebum

[Patch]

I thought about the best way taking into consideration the 2 suggestions and will set that up this evening, I too am curious as too at what point the carb body will back flow.

Made a purchase some years back from a fellow that was attempting his own repairs. We know that bowl volumes are very important for near WOT running; he was telling me that there was a leak from one of the bowl drain plugs. After stripping the bike down for mods what I found was an epoxy poor into  the base of the bowl!? To us this is worth somewhat of a giggle right. But for him he was stuck on the problem of stopping that pesty leak  which we would thru experience know the floats are stuck open, the contours of the casting is why he believed the leak came from the drain screw.

Thing on pressure, I get where Ben is coming from and in my minds eye I see the correlation, the difference is is that I am taking into consideration a lesson learned along the way, the word "intuitive" kind of like assumption. Sometimes our experiences lead us to both. Nothing discussed here as not caused me to question my thinking, I've said this many times "I am a better man because I hang with U's"

The scenario we've been discussing is possible under the correct conditions and I hope to find them. What tripped m was the implication of pressure. Break the problem down we have one cause and one result, but the physics in between  don't add. Gravity is a form of pressure, in a cylinder the force of gravity apply a pressure that contains some type of mass this case fluid - measured at the base of the cylinder would be the total pressure or force. But the higher up the cylinder we measure the less force we find! Why does that matter, because the only pressure in this scenario is the fluid above the carb ports.

This is why. the hand pump is applied to 15 lbs to simulate expansion pressures in a closed loop, this engine is not a closed loop, so the pressure drops, only the operator can choose to build more pressure, the pressure drop time is what we look to for clues on where the leak is coming. The leak is a restriction or say a resistance: a resistance to what? To atmosphere or A#1. So here's a surprise, crank journals in this case are a good comparison. The journals are pressurized to a something from 60-90 lbs depending on engine: the journals must maintain a control spill or leakage and that leakage is then accumulated in the sump. Remember that control leakage was just pressurized to 80issh psi, what then is the pressure of that thermal, liquid bearing material/oil? As it is near atmosphere the only pressure/force is gravity so the weight of the volume cooling in the sump. The very same printable applies here; the 15 lbs ceases to be relevant after it leaves the area of resistance (crack, failed gasket, hole).... The remaining force is only the gravity from the displaced fluid. What then takes over is balance, the fluid level will seek its balance, in this case rise up the intake and carb bore, the only force applied to overcoming resistance such as density and surface tension is the weight of that fluid above porting and it can not rise higher then the balance or set resting level, what ever that might be.

The big question is can the fluid drain via overflow hose? Yes under the right contentions and @ atmosphere it could in theory drain a low as the top of the bowls spout, proving the bowl remains void of air. 

 

[cowpuc]

On 10/16/2020 at 3:28 PM, Popsnana19655 said:

Water was from the carburetor overflow tube I will be starting the tear down after doctor appointment. Anyone got a link for a cheap gasket set. 83 xvz 1200

 

15 minutes ago, Patch said:

I thought about the best way taking into consideration the 2 suggestions and will set that up this evening, I too am curious as too at what point the carb body will back flow.

The big question is can the fluid drain via overflow hose?  """

 

15 minutes ago, Patch said:

 

Patch,, maybe take a quick read of Pops post from the 1st page of this thread.. Test till the cows come home but in this case it appears that Pops successfully proved Bums theory and moved on LOL

[saddlebum]

20 hours ago, Patch said:

I thought about the best way taking into consideration the 2 suggestions and will set that up this evening, I too am curious as too at what point the carb body will back flow.

Made a purchase some years back from a fellow that was attempting his own repairs. We know that bowl volumes are very important for near WOT running; he was telling me that there was a leak from one of the bowl drain plugs. After stripping the bike down for mods what I found was an epoxy poor into  the base of the bowl!? To us this is worth somewhat of a giggle right. But for him he was stuck on the problem of stopping that pesty leak  which we would thru experience know the floats are stuck open, the contours of the casting is why he believed the leak came from the drain screw.

Thing on pressure, I get where Ben is coming from and in my minds eye I see the correlation, the difference is is that I am taking into consideration a lesson learned along the way, the word "intuitive" kind of like assumption. Sometimes our experiences lead us to both. Nothing discussed here as not caused me to question my thinking, I've said this many times "I am a better man because I hang with U's"

The scenario we've been discussing is possible under the correct conditions and I hope to find them. What tripped m was the implication of pressure. Break the problem down we have one cause and one result, but the physics in between  don't add. Gravity is a form of pressure, in a cylinder the force of gravity apply a pressure that contains some type of mass this case fluid - measured at the base of the cylinder would be the total pressure or force. But the higher up the cylinder we measure the less force we find! Why does that matter, because the only pressure in this scenario is the fluid above the carb ports.

This is why. the hand pump is applied to 15 lbs to simulate expansion pressures in a closed loop, this engine is not a closed loop, so the pressure drops, only the operator can choose to build more pressure, the pressure drop time is what we look to for clues on where the leak is coming. The leak is a restriction or say a resistance: a resistance to what? To atmosphere or A#1. So here's a surprise, crank journals in this case are a good comparison. The journals are pressurized to a something from 60-90 lbs depending on engine: the journals must maintain a control spill or leakage and that leakage is then accumulated in the sump. Remember that control leakage was just pressurized to 80issh psi, what then is the pressure of that thermal, liquid bearing material/oil? As it is near atmosphere the only pressure/force is gravity so the weight of the volume cooling in the sump. The very same printable applies here; the 15 lbs ceases to be relevant after it leaves the area of resistance (crack, failed gasket, hole).... The remaining force is only the gravity from the displaced fluid. What then takes over is balance, the fluid level will seek its balance, in this case rise up the intake and carb bore, the only force applied to overcoming resistance such as density and surface tension is the weight of that fluid above porting and it can not rise higher then the balance or set resting level, what ever that might be.

The big question is can the fluid drain via overflow hose? Yes under the right contentions and @ atmosphere it could in theory drain a low as the top of the bowls spout, proving the bowl remains void of air. 

 

Keep in mind Patch that water always finds its own level So just for argument sake consider the carb float bowl as being empty The rad is full the cylinder has a flaw allowing water to enter on top of the piston and the intake valve is not closed but the exhaust is. The water level in a full rad is higher than the top of the carbs. in finding its own level the water leaks into the cylinder into the intake fills the venturi where it can make use of a number of passages to enter the float bowl. You keep comenting on the needle seat being closed but that passage does not enter the venturi that is only a shut off for fuel entering the bowel from the fuel line. there are numerous other passages which if you ever rebuilt one of these carbs you would notice. Now add pressure as in testing and you overrule the water level principle based on gravity etc. and drive the water from the high pressure area to the low pressure area.

The other possibility for the source of internal coolant leaks is if the intake is closed and there is a crack in the head between the intake passage and water jacket in the head. Which @Popsnana19655would make having the head checked for cracks a good idea before reinstalling it

Edited October 31, 2020 by saddlebum