Sectioned CV carb body

[DELL82]

Does any one know of the thread/link showing a CV carb body that has been sectioned, cut with saw, to show the internal channels for air and fuel. Some time ago I was linked to a site or thread that had such a file. I copied it but have lost the file and cannot find it.
My problem is that, at idle, I am not getting fuel to the #4 carb, viewed using a color tune plug. When I open the enrichment ckt I get fire.
When I pull the plug after a long 100 mile ride the plugs are perfect, but at idle it runs on three cylinders.
I have pulled the top and bowl of the carb and blew out the available channels to no avail.
HELP

[Tat2demon]

Have you checked the port to make sure you dont have a screw tip broken off in it?

[motoman]

Have you checked the port to make sure you dont have a screw tip broken off in it?

Could be a possibility, but unlikely as the later carb's idle mix. screws have a shoulder that hits BEFORE the needle tip seats(assuming these are XJ original carbs). The idle circuit IS still restricted from something that's not supossed to be in there not allowing vacuum to draw the fuel at lower rpm's. A weak spark at low rpm in that cyl. will also cause a low vacuum draw. Just throwin' out ideas to consider.

[DELL82]

I have installed the DC-1 coils and have about 45K volts now. As seen in the color tune plug there is plenty of spark. My carbs are original and the adj, screws are flat not pointed. On assembly the screws were unscrewed 2.5 turns.
Still looking for the sectioned carb file.
Trying to find out where the vacuum comes from that sucks fuel through the bowl jet to the cylinder. When viewing the color tune plug zero fuel is coming until I open the enrichment ckt. then the flames are seen.

[Rasputin]

Try this thread and see if it helps any.
http://www.xs11.com/forum/showthread.php?t=20907&page=2

[motoman]

I have installed the DC-1 coils and have about 45K volts now. As seen in the color tune plug there is plenty of spark. My carbs are original and the adj, screws are flat not pointed. On assembly the screws were unscrewed 2.5 turns.
Still looking for the sectioned carb file.
Trying to find out where the vacuum comes from that sucks fuel through the bowl jet to the cylinder. When viewing the color tune plug zero fuel is coming until I open the enrichment ckt. then the flames are seen.

Haven't seen where you went to the extent of removing emulsion tubes after removing slides and main jets. If not, i would advise removing slides(don't mix them up or diaphram springs), remove main jets(don't loose washer under jet), and tap emulsion tube out top-side of carbs. Use a 38cal. nylon(no brass or metal allowed, period) bristle barrel cleaning brush and run up and down inside emulsion tubes to clean. Then use a wooden toothpic(again, no metal pins, paperclips, etc. allowed as any scoring WILL change flow charecteristics) and run into and spin around all the tiny side holes, same procedure for pilot jets....nothing metal allowed. Doing that to internal pieces will atleast eliminate that as an issue with idle circuit. If everything is done to carbs as far as cleaning to a T, no reason for idle circuit not to flow fuel.

[natemoen]

Trying to find out where the vacuum comes from that sucks fuel through the bowl jet to the cylinder.

The vacuum comes from the pistons moving up and down. As the piston moves down it sucks through the carb. As the air moves past the various holes in the carb it creates a low pressure area inside that hole and then sucks the fuel through the hole.

[mlew]

This is a great cutaway article on CV carbs from the XJbikes website.
http://www.xj4ever.com/inside%20your%20carbs.pdf

[CaptonZap]

This is a great cutaway article on CV carbs from the XJbikes website.
http://www.xj4ever.com/inside%20your%20carbs.pdf

Now that is a keeper! Thanks for sharing. CZ

[motoman]

The vacuum comes from the pistons moving up and down. As the piston moves down it sucks through the carb. As the air moves past the various holes in the carb it creates a low pressure area inside that hole and then sucks the fuel through the hole.

.......same as blowing across the top of a straw in a glass of water. Having said that, that's why fuel levels are critical. Stick that straw farther in the water, the less blow across the top it takes to lift fuel upward.....low fuel level equals more vacuum draw equals lean........high fuel levels equals less vacuum draw equals rich......'just right' equals good fuel/air ratio equals complete burn/combustion(or as close as can be expected).

[DELL82]

I want to thank mlew and rasputin for the informative links, they are the ones I was looking for.
I also want to thank all other responders for their suggestions and thought, well done. I will study the cutaways and try and clear my carb passages. When all is well I will report what I found. Again many thanks to all.