Fuel and vacuum line routing off carb

I would suggest fuel tap, make sure its turned on or reserve if your low on fuel. If there is no on/off/reserve you may have a vacuum operated valve, you might have knocked the vacuum hose off the carby or tap while cleaning the bike etc. The vacuum operated fuel tap works by opening when the engine is turning and are very reliable while the hose is connected. Fuel injection requires a fuel pump and pressure regulator.

Here's S&S's manual for the Shorty Carbs (both E & G):

http://www.sscycle.com/files/7913/7033/9802/51-1012_carb_e__g_series_shorty_carburetors_installation.pdf

On page "10", it states, "Slip fuel overflow hose onto fitting on carb bowl and neatly route behind pushrod tubes. On a big twin model, hose should go toward back
of engine. On a Harley-Davidson Sportster model, hose should go toward front of engine. Exit end of overflow hose must extend down
below engine and away from exhaust pipes."

This is the only "vent" hose (actually, a fuel overflow hose) that I know of.

One line that comes from the top LH side of carb (looking at carb w/o air cleaner) is a carb vent aprox 1/4 " hose. It connects only to the carb & hangs in a wire bracket as a vent tube. The 1/2 " vent line that goes from the valve cover on the rear cylinder goes to the spigot on the air cleaner case & vents the crankcase gases back into the intake of the carb to be burnt. Those are the only 2 lines other than the fuel line that comes from the metal pipe that crosses over to the fuel pump on the other side of bike. That fuel line connects to the carb metal fuel spigot on the side of the carb. That's fuel into carb.

Turn off fuel tank petcock valve. Remove complete air filter assembly. Disconnect fuel hose from bottom of petcock(may have to cut hose clamp off and will have to replace with a regular worm screw hose clamp). Hold a rag around the end of the hose where you are pulling it off to catch and squirted fuel. You then pull hose off the carbs elbow fitting the same way you did at the other end. If hose on carb is not easy to access, you may have to pull the carb out of the rubber boot that connects the carb into the intake manifold. Replace hose with same length of new hose which is 1/4" fuel line hose. Reassemble in reverse order using the above mentioned worm screw hose clamps.

Contact me directly at [email protected] and I'll send you a drawing for the oil lines. The fuel line simply runs from the petcock to the carb between the cylinders. Nothing special about it's routing.

Steve

In 1996, Harley went to a vacuum operated petcock. If you'll look on the backside, you'll see a small vacuum hose running to the petcock. The petcock is opened with vacuum being applied to a diaphragm. If this diaphragm gets a hole in it, it'll leak fuel sometime and other times will not allow fuel to go to the carb leaving you stranded with a full tank of fuel but none in the carb. You can drain the tank by loosening the large nut and using a large funnel to catch the fuel in an empty gas can. Take the two hose off, fuel and vacuum, remove the petcock. Take the four small screws out of the baskside of the petcock that holds the square plate on. Notice how the parts come out as you take the plate off slowly. Once you have the diaphragm out, hold it up to a light and gently stretch it. If you find a hole, you need to replace the diaphragm. You can get a replacement part at you local dealership. Personally, I'd rather replace the petcock with a high quality manually operated one. Of course she'll have to turn the fuel off and on old school style but you'll never have another petcock problem. I think the Pingel petcock is the top of the line. I have one on each of my personal bikes. They're pricey but they are excellent quality products. If you do this, don't forget to plug the vacuum hose. Better yet, if you can get to it, the hose has a "Y" fitting in it. Remove the hose with the "Y" fitting in it and replace it with a single hose that goes to the VOES switch.

Ride Safe
Steve

Well, pull the fuel line loose from the carb, put it in a catch can, and spin the engine. The '96 and later Harley's have a vacuum operated petcock if it is still stock. It gets vacuum from the intake maniold or backside of the carb through a small vacuum line. The hose plugs onto the backside of the petcock. If you're not getting any vacuum or the diaphgram in the petcock is damaged, you won't get any fuel to the carb.

Also, try loosening your fuel cap. Don't take it completely off just good and loose. If the fuel tank vent in the cap is plugged, a vacuum will build up in the fuel tank quickly and stop the flow of fuel.

Are you sure you have your ignition system timed and wired correctly?

Steve

Ok, first off, this ain't no Yamaha you're messing with. It's a completely different motorcycle in most every way. Not saying it's better or worse than the *** bike but it's different.

It has two cables, this is correct, but only one carb. One cable is the throttle cable and the other is the idle cable. The idle cable pulls the carb shut in the event the throttle plate spring breaks on the carb. It's a safety thing and it was the same way on your Yamaha.

Now, if the front cylinder is not running at idle, I would suspect a vacuum leak somewhere. There are several places where you could have a vacuum leak. Of course, the intake manifold seals could be leaking, the intake carburetor seal could be leaking, or the VOES/ petcock line could be causing a problem. Unless you have taken your air cleaner off for some reason, I'm going to assume that the problem is in the petcock.

Your bike has one of the vacuum operated petcocks in the tank unless it's been changed already. Vacuum from the engine opens the petcock allowing fuel to the carb when the engine is running but when the engine stops, the vacuum disappears and the petcock closes. Supposedly. This is the worst piece of junk Harley ever put on their motorcycles. They do two things, they quit working and won't let fuel into the tank or they cause a small vacuum leak that will cause the bike not to idle properly. I suspect you have the latter case.

Drain your fuel tank by loosening the petcock and allowing the gas to run out around it. Catch the fuel with a large funnel and an empty fuel can large enough to hold the fuel in your tank. Once empty, disconnect the two hoses and remove the petcock. On the backside of the petcock, there is a square plate. Remvove the four small screws and take the plate off. There will be a diaphragm, a spring, and needle under the plate. Remove the plate carefully so you can see how it goes back together. Hold the diphragm up to the light and gently stretch it while looking for holes. If you find a hole, you'll have to either buy a new diaphragm and repair your petcock or , better yet, replace the entire petcock with a manually operated one. A Pingle petcock is a very high quality valve and you'll like it but it is pricey. If you buy an OEM petcock, get one for a 1995 or earlier bike. You will no longer need the vacuum line and you can plug it with a small bolt or something to stop the vacuum leak.

This vacuum line comes off a nipple at the backside of the carb and it feeds vacuum to two things. It's a 3/16" hose that goes up to the VOES switch mounted on the frame under the tank. From there it "Y's" off to the smaller hose that goes to the backside of your petcock. Take your fuel tank off and inspect this hose. Look for cracks. If you go with the manual petcock, eliminate the small portion of the hose by replacing the hose that runs to the VOES with the single hose instead of the "Y'd" hose.

As for the idle speed of you engine, it should be set at about a thousand RPM. Look at the top of the carb. There is a screw near the top on the right side of the carb. That is the throttle stop screw. It controls the idle speed of the engine. Turn the screw clockwise to increase the idle speed.

Ok, try what I've written here. If it doesn't work, get back with me.

Good Luck.
Steve