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If there's a moderator within the sound of my keyboard, this link should be stickied, IMHO:

Care & Feeding Of The Keihin Carb

This primer on the CVK40 (and generally, all CV carbs) has bounced around from elusive, and sometimes obsolete, websites; recommend keeping track of the link, perhaps prudently printing out the article.

Content is profound; I'm not kidding (now, though I often am!). :)

Four video clips on the KLR650 carburetor, the Keihin CVK40:





 

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I got some learning to do, but thanks for posting this. Super informative already.
 

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I had a link to that article in one of my videos and was advised that the link was dead a couple of days ago. Found the new source and put that in the video, but just to be on the safe side I made a .pdf out of it and saved it.

As Damocles says, it's been bounced from pillar to post in the past 15 years.

Tom
 

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This "Care and Feeding of the CVK40" article is very good, but I found a small error.

"Pilot System-Steering you to better lows" The very last sentence.

The pilot mixture screw Primarily controls Fuel not air.
So opening the screw richens the idle mixture.

Yea, I know, pickey, pickey, pickey.
 

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Discussion Starter #5 (Edited)
This "Care and Feeding of the CVK40" article is very good, but I found a small error.

"Pilot System-Steering you to better lows" The very last sentence.

The pilot mixture screw Primarily controls Fuel not air.
So opening the screw richens the idle mixture.

Yea, I know, pickey, pickey, pickey.
My understanding, the idle mixture screw meters air/fuel mixture at idle.

Yet, the Kawasaki nomenclature for the screw (Fiche Reference 16014) is, "SCREW-PILOT AIR."

For discussion, I copied the last sentence in the "Care and Feeding" article:

"When you adjust the pilot screw that's under the carb, you are varying the amount of air premixing with the gas before it enters the venturi."

Generally, a pilot screw on the intake side is an "air" screw; on the engine side, a "fuel" screw.

Again, I thought the CVK40 idle mixture screw controlled the flow of a mixture of air and fuel from the pilot jet to the venturi; backing the screw out fuel-enriched the idle mixture, or so I thought.
 

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This "Care and Feeding of the CVK40" article is very good.

The pilot mixture screw Primarily controls Fuel not air.
So opening the screw richens the idle mixture.
My understanding, the idle mixture screw meters air/fuel mixture at idle.

-------- backing the screw out fuel-enriched the idle mixture, or so I thought.
Did we not just say the same thing?

I will suggest at this point, the throttle plate and Large idle speed screw Primarily control the low speed air supply.
 

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Did we not just say the same thing?

I will suggest at this point, the throttle plate and Large idle speed screw Primarily control the low speed air supply.
Damocles,
The word of the day is "primarily".

I almost hated to have to even mention the error because of this 'exact' possibility! Useless Banter! Cluttering up a good thread!

Moderators, You may 'Delete' any and all of these newer postings if you deem appropriate.
If you can correct the error on the link!

And then maybe 'lock the thread'?
It is/was stickied. They do float or rotate the order with newer postings.
Which is part of the reason I occasionally post in my own threads, move'em to the Top again!
 

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Discussion Starter #12 (Edited)
You DID bring it up, Paul!

And, is the question answered? That is, does the idle mixture screw, "SCREW-PILOT AIR." control air only, fuel only, or an emulsified air/fuel mixture?
 

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Emulsified fuel, of course. Carbs don't deliver fuel because the resulting droplets would be too large to readily break up, much more critical to meter accurately/adjust. One has only to look at the air bleed ports/holes in the sides of the main circuit emulsion tube or in the integral portion of the pilot jet.




You DID bring it up, Paul!

And, is the question answered? That is, does the idle mixture screw, "SCREW-PILOT AIR." control air only, fuel only, or an emulsified air/fuel mixture?
 

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Discussion Starter #14
Emulsified fuel, of course. Carbs don't deliver fuel because the resulting droplets would be too large to readily break up, much more critical to meter accurately/adjust. One has only to look at the air bleed ports/holes in the sides of the main circuit emulsion tube or in the integral portion of the pilot jet.
I hear you!

Thus, I think, "Idle Mixture Screw" more accurate and informative nomenclature than, "Screw, Pilot Air," as Kawasaki designates the part.
 

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Discussion Starter #15
Speaking of "mixtures," the "choke" (starting enricher) system mixes air and fuel. When the plunger is withdrawn from the carburetor, opening a fuel port, an air passage simultaneously opens, producing a fuel-rich air/fuel mixture fed into the venturi. Thus, the "choke" (starting enricher) functions as a sort of, "mini-carburetor."

Leastwise, that's how it looks to me; clarification and correction welcomed.
 

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Semantically, I think, not exactly, Paul!

At issue: Does the idle mixture screw regulate fuel flow only, air flow only, or . . . an emulsified mixture of air-and-fuel?
Not to get too technical, but you can't really create an emulsification between a liquid and a gas.. Air being the gas.

Definition of emulsify
emulsified; emulsifying
transitive verb
: to disperse in an emulsion

emulsify an oil

; also : to convert (two or more immiscible liquids) into an emulsion
 

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If there's a moderator within the sound of my keyboard, this link should be stickied, IMHO:

Care & Feeding Of The Keihin Carb

This primer on the CVK40 (and generally, all CV carbs) has bounced around from elusive, and sometimes obsolete, websites; recommend keeping track of the link, perhaps prudently printing out the article.

Content is profound; I'm not kidding (now, though I often am!). :)
There have been numerous times that I have wished these videos were in this Thread!

Now they are at least connected, https://www.klrforum.com/199609-post5.html

Maybe a moderator could move them to post #1 or at least page 1 with Toms PDF?
 

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Done and did.
 
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The videos have been up on YouTube for quite a while now. I've never paid much attention to how often they get viewed, but I have always watched the comments and tried to respond to them in a timely manner. The vast majority are positive and many ask questions.

YouTube just notified me that the videos hit over 100,000 views a little while ago.

A lot has happened since these videos were made some five years ago. Many of the comments posed questions that might have been and should have been covered in the videos. Ethanol has become a bigger problem and I should have covered that and mechanical cleaning of some of the parts, especially the inlet valve seat. I've learned a lot about the other CV and CVK carbs that are being used. The inlet and vent elbows have changed and inline filters have been added.

What I used to be able to do, on all my videos, was add an annotation to the video. That allowed me to clarify things that popped up as questions in the comments. It allowed me to make corrections for slips of the tongue that happen when an unscripted hooligan with a camera makes videos. I could easily add links to supporting videos, websites, and documents. I could add torque values, sizes, and generally anything of value that I didn't think of during my unscripted yammering.

About a year ago YouTube dropped support for adding annotations. There was much hue and cry from the content providers but to no avail. It made no sense and hurt a lot of content providers but YouTube was and is focused on portable devices. Annotations suck on portable devices but the providers that got hurt the most were the gamers and instructors and those sorts of videos suck on portables anyway! I was unable to add further annotations to videos at that point and the gamers were pretty much out of business.

What's worse, YouTube stopped supporting existing annotations early this year so all of the annotations that were in videos went away. Now what I'm faced with is finding a way to add text to videos that are currently published on YouTube. There's a way, I'm sure, but it's going to take a lot of energy to make it happen. @pdwestman helped me with some post-publication changes to one of the balancer lever videos where we removed some confusing content from the middle of a video. That content had simply been covered by an annotation before. It was a pain to remove that content even knowing exactly what needed to be removed. Adding back annotations should be equally painful as I have to watch every video, make notes and try to remember stuff I did with annotations years ago. Frankly, it might not happen.

It would be easier to go back into post-production and add the text and re-upload to YouTube, but then every link to the videos (and there are thousands) would be broken. Think 'Photoshop Fiasco' on a much smaller scale. If I were to do that I'd be sorely tempted to simply say 'screw YouTube' and host them on souperdoo.com. YouTube has made several blunderous changes in the past couple of years; I wouldn't have to put up with whatever is coming from them in the future.

As you watch these, and my other videos, if you see something that sounds like a mis-speak, is flat out wrong, or some info might well be added understand that it probably was there before the annotations were dropped. Read through the comments and see if your question has been asked before. If you need clarification please post a comment. I get notified of all comments and will answer quite quickly.

As always, thanks for watching and thanks for the use of the hall...
 
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