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Carb "frozen"?


havoxx

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So I went out to arcadia to ride my bikes this weekend, I gotta say, the banshee was running great, but then all of a sudden, the right carb started to "freeze" it actually got insanely cold and from the looks of it, just wouldn't work. if I let it sit for a while, it would be fine after the carb warmed up, but then it would just freeze and start bogging after a while.

 

If anyone knows what could cause this, please let me know, I was running 40:1 Yamalube on 93 octane, it's a 87 completely stock 'shee.

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Icing occurs when the atmospheric air contains significant levels of water vapor; as the air is drawn into the engine through a carburetor it is cooled sufficiently to cause that vapor to condense out and freeze on the butterfly valve. This cooling has two causes: the air pressure drops due to the engine suction and due to the increase in speed through the butterfly valve (in part-throttle operation) which drops the air temperature; and the liquid gasoline being introduced into the airstream must evaporate, and the heat of evaporation is extracted from the airstream, cooling it. The temperature in the carburetor can drop below the freezing point of water, and if the air is humid, ice can form inside the carburetor. As the ice builds up, less air can pass through the carburetor, causing a drop in power and, in severe cases, the engine will eventually stall.

 

Temperature drops of 20

Edited by Badapwned
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Damn Badapwned, that's way too much for my brain to process. lol. Never seen anything like that happen. But then again, look where I live. Mid-Atlantic and close to the ocean. Air temps are usually not that cold.

 

 

Yea I was in central florida, it was only about 50-60 degrees, but it was humid as hell. Thanks for the help.

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Icing occurs when the atmospheric air contains significant levels of water vapor; as the air is drawn into the engine through a carburetor it is cooled sufficiently to cause that vapor to condense out and freeze on the butterfly valve. This cooling has two causes: the air pressure drops due to the engine suction and due to the increase in speed through the butterfly valve (in part-throttle operation) which drops the air temperature; and the liquid gasoline being introduced into the airstream must evaporate, and the heat of evaporation is extracted from the airstream, cooling it. The temperature in the carburetor can drop below the freezing point of water, and if the air is humid, ice can form inside the carburetor. As the ice builds up, less air can pass through the carburetor, causing a drop in power and, in severe cases, the engine will eventually stall.

 

Temperature drops of 20

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Again, I was not trying to be a smart ass or anything, a "venture" is completely different then a "venturi"

 

If that guy went to search the internet for "ventures" he would end up looking at joint ventures between companies.....with a big WTF sign above his head lol

 

 

A venturi is a common and old technology.

 

 

"Sure you could've...since there's no butterfly valve in a banshee carb, it's a throttle slide. TOTALLY different.... "

 

 

Again, not to be an ass, the butterfly is no different then a slide in the banshee carbs. Its to regulate flow, increasing and decreasing the velocity through the carb.

 

 

The carb itself is a single, non-adjustable venturi. If you every wondered why a car carb or any other carb is shaped like it is, its because their trying to achieve the venturi effect.

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My point was a butterfly valve and a slide are completely different in both design and operation...and a flat blade piece of metal is more prone to freezing than a slide.

 

I would be looking for water in the fuel, a bent needle, a burr on the inside of the housing where the slide is..etc.

 

I understand the whole venturi thing, it's purpose...design, etc.

 

Lectron even designed a HV (high velocity) type carb for two reasons...

 

One...for use in competitions where smaller ID carbs were regulated. The airbox/boot side was 4mm larger than the intake side, but necked down in the middle even further for the ID limits..then opened back up on the intake side....

 

As well as speeding up the air/fuel intake charge into a larger motor that didn't have as strong of a pickup signal.

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My point was a butterfly valve and a slide are completely different in both design and operation...and a flat blade piece of metal is more prone to freezing than a slide.

 

I would be looking for water in the fuel, a bent needle, a burr on the inside of the housing where the slide is..etc.

 

I understand the whole venturi thing, it's purpose...design, etc.

 

Lectron even designed a HV (high velocity) type carb for two reasons...

 

One...for use in competitions where smaller ID carbs were regulated. The airbox/boot side was 4mm larger than the intake side, but necked down in the middle even further for the ID limits..then opened back up on the intake side....

 

As well as speeding up the air/fuel intake charge into a larger motor that didn't have as strong of a pickup signal.

 

 

I agree with everything above.

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