verslagen1 wrote on 09/24/11 at 19:00:38:


Okay, okay,...  There is work done, and energy used in order to move the diaphragm a tenth of an inch to open up the valve to let the fuel flow.  

It is a tiny force applied for an instant to move the diaphragm.  Once the diaphragm is moved, no more work is being done.

I'd wager the amount of energy used would be less than an erg,... less than one billionth of a horsepower, corrected for time.  This amount of energy is small compared to the amount of work being done by the engine.  It is like comparing the amount of energy used for your Nikon Coolpix to take a picture of a space shuttle taking off, to the amount of energy used by the space shuttle taking off.

Space shuttles notwithstanding, a Raptor petcock, for all of its advantages, does not free up any energy to be used elsewhere.

BTW, both our bikes in the Double RYCA build have had the stock vacuum petcocks replaced with,.......




                     wait for it,..................

                                                          RAPTORS!!!!!!



                                                   yay

Why did your idle pick up 200 rpm from changing the petcock to a Raptor?

Because your bike took one more step towards being a true pork eating Carnivore !!


--------------------------


Seriously, you capped off a potential vac suction leak draw point ....

.... and you made sure your bowl was always full right up to the top fill point at all times.


Either (or both acting together) may have richened your idle mixture slightly enough to make your idle speed go up a little bit.

Plus the fact you are running the snot out of your bike now since it is running better for you, so you are getting your engine loosened up a bit more than you used to (and your idle speed goes up a bit for that reason too).

Gyro: the force of gravity keeps your a$$ on the floor.
The kind of force we are talking about is called "elastic potential energy"
This is the force required to keep the springs (don't forget the vacuum line is a spring as well) at tension. Energy is expended to apply this force.
This may (or may not) help explain what I am talking about:
When I was in HS our science teacher attempted to demonstrate how water will boil in a vacuum. He put a beaker of water under a bell jar and began pumping the air out with a vacuum pump. Nothing happened. The spring (the air in the jar) was too strong for the vacuum pump to lower the vacuum enough to boil the water. I suspended a balloon in the jar full of water, inflated it some to displace some water, hooked the balloon up to the same vacuum pump and turned it on. Nothing happened for some seconds, then all of a sudden the balloon deflated and the water boiled off enough vapor to displace the volume of air in the balloon. Why? Because the spring (air in the balloon) was a lot smaller than before. The vacuum pump had to keep applying force to maintain the vacuum in the bell jar. I closed the valve on the vacuum line and shut off the pump. Then the force of the difference of pressure, in this case elastic potential energy, kept the balloon deflated.
My point here is that energy is used to keep tension on any spring. If I had a vacuum gauge I could calculate how much energy is needed to keep the petcock open.
Vacuum in a carb can be created in two ways: resistance to airflow caused by the air filter, and air flowing over an orifice in the carb. Putting in a less restrictive filter allows more air which pulls more fuel (assuming your jet system will supply it). Same thing if you plug the orifice, as you do when installing  raptor.

No.

The fact that the vac petcock is there does not effect the average vacuum per se, only the volume.  So the only effect is to create a tiny lag in response.

arteacher wrote on 09/25/11 at 08:01:52:

To hold the valve open, the vacuum has to be there, and it must stay there, and it will stay there as long as the engine is running. So it is fact that energy is being used, (gasoline) and vacuum is being used but not consumed, therefore there is no reserve vacuum left after changing to the Raptor to be used for anything else that actually consumes vacuum (like vac wipers), nor does the vacuum increase for lack of the valve.

Change it to an air pressure operated valve,....same thing,....air pressure must be there and stay there, and that consumes energy, (motor running) but again, no air is being consumed, so if you take the valve away, there is no air reserve left over to operate anything else that actually consumes air, nor does the air pressure increase.

But then, you knew all that

Who is fighting????
We had a discussion and I learned a few things.