well strictly speaking you are correct 2m but
I was trying to find a simple way of explaining why a slide stays up when you cover the top vent without resorting to science , formulae and big words. There is simply no point in going into great depth about potential and kinetic energy, vacuums and pneumatics etc, nothing would be achieved
The easiest way I can think of demonstrating the action of this phenomena to those that do not understand how a CV slide works is to take a bicycle pump and invert it so the outlet is facing up and the handle is facing down . Push the pump handle all the way in and then close off the outlet with your finger.
The handle does not fall ............it stays where it is despite its weight pulling it downwards due to gravity.
Why is this ?
Now keeping a finger on the outlet pull down hard on the pump handle and see what happens ......
It resists your pull and when released jumps straight back up to its former position.
Why did it do this.?
When you pull on the bicycle handle what is it that resists the combined energy of the weight of the handle and the energy of your pull ?
See its already got far too complicated for most folk to maintain any interest ....suffice it to say that vacuum is involved . The slide is held up by the air seal created in the void above the diaphram. The weight of the slide is potential energy pulling down on the air pressure in the sealed void above the diaphram.
If the void was hermatically sealed the slide will stay up indefinitely because there is insufficient force applied by the weight of the slide to overcome the air pressure in the void. If you were to apply more force on pulling the slide down it would begin to create a vacuum in the void because something has to take the place of the extra space created in the void when the slide drops . that something would be a vacuum.
So very simply put that is how the carb slide (and pump handle ) stays up and how vacuum is involved in the process although in hindsight vacuum is probably not the best word to choose to explain this process.
To further complicate things all slides have a tiny hole drilled vertically through the body which forms an air jet. This hole allows a small amount of air to transfer from the void above the diaphram to atmosphere and thereby allows the slide to rise at a pre determined regulated rate due to the vacuum created by the engine .
Tuners vary the diameter of the hole in the slide to vary the rate of lift of the slide to effect throttle response characteristics.
This is why the slide should fall very slowly in a set amount of time provided that the diaphram is perfectly sealed.
if there is any sudden drop of the slide that indicates that there is an air leak somewhere or an additional air source is available to the void above the diaphram .
I was trying to find a simple way of explaining why a slide stays up when you cover the top vent without resorting to science , formulae and big words. There is simply no point in going into great depth about potential and kinetic energy, vacuums and pneumatics etc, nothing would be achieved
The easiest way I can think of demonstrating the action of this phenomena to those that do not understand how a CV slide works is to take a bicycle pump and invert it so the outlet is facing up and the handle is facing down . Push the pump handle all the way in and then close off the outlet with your finger.
The handle does not fall ............it stays where it is despite its weight pulling it downwards due to gravity.
Why is this ?
Now keeping a finger on the outlet pull down hard on the pump handle and see what happens ......
It resists your pull and when released jumps straight back up to its former position.
Why did it do this.?
When you pull on the bicycle handle what is it that resists the combined energy of the weight of the handle and the energy of your pull ?
See its already got far too complicated for most folk to maintain any interest ....suffice it to say that vacuum is involved . The slide is held up by the air seal created in the void above the diaphram. The weight of the slide is potential energy pulling down on the air pressure in the sealed void above the diaphram.
If the void was hermatically sealed the slide will stay up indefinitely because there is insufficient force applied by the weight of the slide to overcome the air pressure in the void. If you were to apply more force on pulling the slide down it would begin to create a vacuum in the void because something has to take the place of the extra space created in the void when the slide drops . that something would be a vacuum.
So very simply put that is how the carb slide (and pump handle ) stays up and how vacuum is involved in the process although in hindsight vacuum is probably not the best word to choose to explain this process.
To further complicate things all slides have a tiny hole drilled vertically through the body which forms an air jet. This hole allows a small amount of air to transfer from the void above the diaphram to atmosphere and thereby allows the slide to rise at a pre determined regulated rate due to the vacuum created by the engine .
Tuners vary the diameter of the hole in the slide to vary the rate of lift of the slide to effect throttle response characteristics.
This is why the slide should fall very slowly in a set amount of time provided that the diaphram is perfectly sealed.
if there is any sudden drop of the slide that indicates that there is an air leak somewhere or an additional air source is available to the void above the diaphram .
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