Post by Bashan on Dec 24, 2013 19:05:54 GMT -6
Boy, did I drop the ball!! First of all, yes, the ACV[/I] diaphragm should be completely dry! The slide diaphragm can have a little gas film on it. I dug out my stuff from when I mapped all this out and Alley, you are correct, it has nothing to do with the slide.....and you are a turkey...gobble, gobble. It's an old joke from my teens and....MOVING ON! I think I had too much fun last night while trying to post.
I dug out my notes, found some old pics, and made some new pics. So not to step on the wizened Mr. Oop's elucidation but get the hell out of my way Mr. Tryptophan! It's an amino acid in turkey meat, it's what makes you sleepy after......MOVING ON!
First of all, remove the two screws that hold the ACV plate on. No need to pull the plate off, it pops off and hits you on the forehead....everytime. The spring follows close behind and hits you in the eye. After you get back from the emergency room you should take a few pictures of your carb and then throw it out because that ACV plate is NEVER going back into place due to that accursed spring!
Don't even try, you'll just end up back at the emergency room.Let's see, I think this is the right pic, I can't see very well:
That's the diaphragm and the piston, or plunger. Those arrows show where the passages run. The yellow arrow shows the short ACV valve passage to the top of the carb. The other passage is the low speed circuit and is somewhat complex. At least it seemed complex last night, and it's getting more complex every time my bud Luther (not kidding) "freshens" my drink. He makes all of his own "mixers" in a special container (bath tub) with only the highest standards (none). I think his "mixers" may have something to do with my vision problems....either that or that damn spring.
Here's where the passages terminate on top of the carb:
Now those passages are terminating in what I call the high pressure chamber. That deviates from all of the expert nomenclature but they are all wrong and I am right by virtue of four of Luther's "mixes". I'm getting righter as the evening progresssssses. I call it the high pressure chamber because it's pressure is higher than the chamber above the diaphragm. Is that really the way you spell diaphragm!!?? Come on!! I do NOT hear a G anywhere. SUE!! Go look up diaphragm for me!! Huh?? Do what?? Now that's just rude and I don't think a diafram would fit there. That's just rude. Moving on...
Here's a diagragm....
The high pressure chamber is at atmospheric level by virtue of this opening:
Which looks like this from above:
And the low pressure chamber is so called because of at least one of these openings at the bottom of your slide:
These openings, one of which contains some kind of a needle, I don't think it matters which hole it goes in, these openings, one of which um...er. These holes are over the lowest pressure in the carburetor due to their approximation to the narrowest part of the venturi. Wooo dog!! That was a sentence! Loother....freshen me! That's what makes the upper chamber lower in pressure, it's not really a vacuum.
If you get everything set up right you should see this in your carb when you just turn on the key:
OK, how does this work? How does what work you ask? I'm asking the questions and how does this work? As Alley said earlier in this tutorial "Rich, I think you should go lay down for a while." Maybe so Alley but how the hell did you get down to Bama and do you really know Sue well enough to give her that long of a hug? You're taller than I thought you would be. Huh? It's because I'm laying on the rug? I knew that...moving on.
The spring keeps the Air Cut Valve open most of the time you're riding. Here is the valve as it would appear when the piston is holding it open:
This allows air to flow over to the low speed circuit which makes a leaner mixture. The yellow is the air flow, the red is the low speed circuit:
The low speed circuit terminates at this opening:
Alley has some fabulous pics of the low speed openings but I can't find them, or my keys, or wallet...
When you shut down your throttle it creates a high vacuum environment ahead of the butterfly and pulls the ACV closed:
Less air to the circuit and more gas to the engine = no back firing due to a lean mixture.
What can we glean from this:
- Gas (a little) is OK on top of the slide diaphragm since the bottom has openings just above the main jet.
- Excess gas on top of the slide diaphragm can indicate too large of a main jet, a over restrictive air cleaner, poor valve gaps, o9r over restrictive exhaust.
- Gas on the outside of the ACV diaphragm is unacceptable since it indicates a leak. I have run a clear vac line from the ACV vac nipple so I could see if gas was getting into the line. It's simple, cheap, and can spot a huge problem.
Sorry about the brain fart, Alley was exactly right. Maybe the pics added something and maybe you got a yuk. [/b]
