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Need a diagram, I have searched, the pics from old threads are gone :crying: Restoring one with all rotted hoses and wanting to just bypass (I live in a warm area.):nerd:
 

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the coolant lines are not there for cold weather....


unless you live where 150 degrees are common..


but go ahead.. your bike.
 

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I removed coolant hoses from my carb when changing out the slide valve diaphragm.
One hose has different ID on the ends so that was re-used to do the bypass.
Link below has the hose routing diagram. Coolant heats up manifold also.
A pic of a hose that was cut off and the piece not used. Cooling system diagram found.
Coolant cross-over pipe hose stayed, manifold to carb was old route, now manifold to TEE on return line to coolant pump.

https://www.vtxoa.com/forums/7-vtx-1300-riders-board/458704-1300c-hose-routing-picture-request-after-fire.html#post4565022
 

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I don't want to cause an arguement here. I just want to understand what the porpous is for doing this?
 

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Discussion Starter #8
I don't want to cause an arguement here. I just want to understand what the porpous is for doing this?
No need for a circuit to keep my carb from icing where I live.

the coolant lines are not there for cold weather....


unless you live where 150 degrees are common..


but go ahead.. your bike.
Yes, they are a carb/intake heater for cold climate. Fuel/air has strong chilling properties and carbs will ice up in cold climates.

I removed coolant hoses from my carb when changing out the slide valve diaphragm.
One hose has different ID on the ends so that was re-used to do the bypass.
Link below has the hose routing diagram. Coolant heats up manifold also.
A pic of a hose that was cut off and the piece not used. Cooling system diagram found.
Coolant cross-over pipe hose stayed, manifold to carb was old route, now manifold to TEE on return line to coolant pump.

https://www.vtxoa.com/forums/7-vtx-1300-riders-board/458704-1300c-hose-routing-picture-request-after-fire.html#post4565022
That's exactly what I was hoping to do route wise except skip manifold, but wanted to see a flow pattern to be certain it was something that could be done with an expectation of reliability. Thank You!
 

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It is for emissions, fuel vapor condensing on cold surfaces becomes liquid. So you need a richer mixture for cold engine to run properly.

Many drag racers have a cool can to reduce fuel temp.

I have not investigated fuel/air density to see what the benefit is.

I had a Nissan truck that I disabled the vacuum valve to reduce air temp(block warm air from exhaust manifold). The carb did begin to ice up, vehicle slowed down.
I restored the vac hose and back to highway speed.. Snowing in South Carolina 1991-92

If I had a free breathing intake with exposed filter I probably would not have done this. I have the stock air box so I do not expect any icing conditions. Warm air from engine side intake holes.
 

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helps to stabilize fuel temperature
helps with vaporization of fuel for a more even and consistent fuel burn....
in all weather and temperature..

carburetor design 101. from the 1970's.. it works..


its like talking to my grandfather.. if I ever had on...
and I am OLD...

a 1964 Harley 900 carb would work better..
 

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Discussion Starter #13
The Main line from the T at the thermostat is long enough and is shaped almost like it was meant to go to the crossover pipe, for now that's how it will be. In my 20 years of motorcycle wrench turning, I've never had a loss of performance, and possibly a placebo gain from bypassing the coolant flow to carbs. Even on high revving sport bikes.
 

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Air cooled twins and triples carbs may have gotten some engine heat from the air box under the seat/tank area.
No direct heating.

H-D carb heat from cylinders...

BMW may have used some exhaust heat to warm the carbs.
Seems I may have seen something like that.
 

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Discussion Starter #15
Air cooled twins and triples carbs may have gotten some engine heat from the air box under the seat/tank area.
No direct heating.

H-D carb heat from cylinders...

BMW may have used some exhaust heat to warm the carbs.
Seems I may have seen something like that.
Honda and Yamaha seem to think folks are gonna ride all winter.
 

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LOL ... this is funny. I live in a cold climate. Rarely have I had a problem with carbs "icing" up, even in the dead of winter. That's right, I ran an open air cleaner and headers in most of my carbed cars / trucks, rarely had an issue, gong down to -40. This goes back to the days of leaded fuel, believe it or not, before anyone coined "winter gas".



On older cars the warm air from the exhaust manifold would warm the air to help the engine run more efficiently. It helps the fuel vaporize better. It also help warm the choke to allow it to open, sooner rather than later having the engine running leaner, sooner (good for emissions) . I ran an open air cleaner and headers, so warm air return was the first to go on my "hot rods". It had to get some kinda cold before it was even the slightest problem. It's unlikely, Hans, that your Nissan truck was icing up. Far more likely the choke was adjusted for warm air return to be there and it wasn't any longer so the choke was likely on somewhat, or if not the colder air had it running lean. Chokes were more often just a bi-metal coil to open and close based on temp. I mostly ran Carter / Edelbrock carbs because they had electric chokes and worked far better in the cold. The guys who ran Holley carbs or their stock Rochester carbs were popping and spitting until their engines got hot ... but it wasn't due to icing.



Performance guys and racers ran coll cans for the fuel for one primary reason. It was easier to cool the fuel than it was the air. As the air and fuel mixed in the carb and intake, the charge got denser ... much denser as the air gave up heat to the cold fuel. Cold air is denser and the charge is therefore denser. Kinda like a small amount of boost. Water injection or water/alcohol injection was used for the same reason. The colder intake charge will also help to cool the cylinder and is less likely to detonate, so one can even advance the timing a bit without hammering pistons.


Chuck is 100% right IMO, it's not there for cold weather. I can run my CRF450X (Keihin carb) at well below freezing and all I need to do is change the needle so it runs richer. The 450X is a reasonably high performance engine so is far less tolerant to A/F ratios than say, my wife's old TTR225, which runs no matter what. I had to adjust the 450X for altitude. Snow mobiles had carbs back in the day too, right? In the case of the 1300 the coolant to the carb is for efficiency and emissions. You may not even know it's missing, and if you do, likely a simple A/F adjustment will keep it rideable.



None of this is to in any way belittle anyone here, but sometimes those of us in colder climates find it kinda funny how people from warmer climates speak regarding the cold and the understanding of what is actually going on.
 

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research....

gasoline freezing at minus 70 "F"

it's the moisture in the air that freezes carburetors...... and the evaporation of gasoline also lowers the air temperature..

how do you think our bodies cool its self..

AKA.. old AIRCRAFT.... look it up....

As our friend..PhilsCBX said....... motor heads are going extinct
 

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Harkon.. Sir,,


I give you Credit.. Control... and Calm.... you are the Man.


to the un-informed... I wrenched on cars OUTSIDE at minus 20 "F"...
. part of my JOB...
 

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LOL, I hear the cold stories all of the time. To be fair, to those that don't regularly experience it, it is quite natural and easy enough to draw some conclusions that may not be 100% accurate, based on the information at hand. Again, there was no intention to goon anyone, as I know I've made my own guffaws regarding other areas of the world. To me, I get a chuckle out of it, but the intention is only to set the record straight. It's all good fun.
 
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