Fuel tank petcock vacuum operated - 2011 Bajaj Pulsar 150

Your bike is equipped with a vacuum operated petcock. There is a fuel hose and a small vacuum hose on the backside of the bike. Vacuum generated by the engine when it is in operation opens the fuel petcock. Make sure that you didn't knock that vacuum line off as well. You can take the fuel line off the petcock and spin the engine to check for fuel flow.

Good Luck
Steve

If the bike is equipped with a carburetor, there is a screen on top of the petcock. No other filter after that unless one was added aftermarket. Take the petcock out of the tank and the screen should come out with it. But, your problem may not be the screen. It may be the vacuum operated petcock itself. In 1996, Harley went to a vacuum operated petcock and they do give trouble such as yours. The diaphragm in the backside of it may have a hole in it allowing it to close at low manifold vacuum or a small piece of trash may be in the needle and seat. Remove the petcock from the tank and take the plate off the backside. Hold the diaphragm up to the light and gently stretch it while looking for a hole.

Good Luck
Steve

If your petcock is a standard replacement part, you must connect the vacuum line to the backside of the petcock. There should have been a vacuum line on your old petcock unless a previous owner has changed the petcock to a manually operated one. The vacuum line comes off the backside of the carburetor and supplies vacuum to the VOES switch and the petcock.

Still even with the vacuum line connected, you won't get fuel until you turn the engine with the starter. The engine must turn to generate the vacuum to open the petcock. If you have a hand operated vacuum pump, you can use this to check the fuel flow from your petcock.

Good Luck
Steve

There's a gland nut that holds the petcock into the tank and pulls it up against the seal. Try tightening the nut. But, in all probability, it's the vacuum diaphragm in the backside of the petcock.

Harley went to a vacuum operated petcock in 1996 and they've been a pain ever since. The diaphragm gets a small hole in it and leaks gasoline or quits opening leaving the rider stranded.

Now, You can repair the petcock if you wish. Get a large funnel and an empty gasoline can. Loosen the petcock and allow the fuel to run out around the nut, catching it in the funnel and directing it into the gas can. Once empty, take the fuel line and the vacuum line off the petcock. The vacuum line is the small line on the backside. Take the petcock out of the tank. Look on the backside and there are four small screws. Take them out and carefully take the back plate off the valve. You'll see a diaphragm, a spring, and needle. Take the diaphragm and hold it up to the light and gently stretch it. You'll probably find a hole. You can get a replacement diaphragm from you local dealer. Reassembly is the reverse of disassembly.

Personally, I'd rather replace the vacuum operated petcock with a high quality manually operated petcock such as Pingel. The OEM petcock will fail on you and leave you stranded with a full fuel tank and an empty carburetor. The Pingle won't. Just install it, connect the fuel hose, and plug the vacuum hose.

Good Luck
Steve

Your bike is equipped with a vacuum operated petcock. To check the petcock out, you must remove it from the tank. I usually use a large funnel and an empty fuel can. Loosen the petcock enough to allow the fuel to run out and use the funnel to collect the fuel in the empty can. Once the tank is empty, disconnect the fuel hose to the carb and the vacuum hose. Remove the petcock from the tank.

On the backside of the petcock, there are four small screws. Remove the screws and the diaphragm and needle in the petcock will come out. Hold the diaphragm up to the light and gently stretch it while looking for holes. If you find a hole, replace the diaphragm.

Personally, I've seen enough problems generated by these petcocks to warranty replacement with a high quality manually operated petcock. I like the Pingle petcocks. They're pricey but they WORK. I've seen too many people stranded with a whole tank of fuel and none in the carb because of these petcocks.

Good luck
Steve

Evidently, you have the vacuum operated petcock on your bike. If you have a hand operated vacuum pump, you can unplug the vacuum line from the back of the petcock and apply vacuum with the pump.

Otherwise, use a large funnel under the petcock and loosen the petcock tank fitting until the fuel starts to flow out. The funnel will catch the gasoline and direct it into a gasoline can.

Good Luck
Steve

You didn't tell me what year Sportster we're dealing with. So, I'll cover a few general things to check.

If your bike is running for about a mile and then stopping and it does this repeatedly, It sounds like a fuel problem. Most likely it's either the petcock or the fuel tank vent system.

First, If your bike is made after 1996, it probably has the OEM vacuum operated petcock. These petcocks are designed to open when the engine is running and close when it stops. There is a small vacuum line that plugs into the backside of the petcock. When the engine is running, this line supplies the vacuum. Check the line and make sure that it hasn't come loose or cracked. It originates behind the carb and goes upwards underneath the tank to the VOES switch and it has a "Y" in the line that reduces the size and then runs to the backside of your petcock.

If it is intact, you'll need a hand vacuum pump to test the petcock for proper operation. Connect the vacuum pump to the rear of the petcock. Remove the fuel line from the petcock. Now, apply vacuum to the petcock with the pump. Fuel should flow from the petcock. If not, the petcock is either bad or the strainer in the tank is stopped up.

Remove the petcock from the tank. Place a large funnel under the petcock and direct the funnel into an empty gasoline can large enough to hold all the fuel in the tank. Loosen the petcock enough so that the fuel runs out at a rate that you can control. When empty, finish removing the petcock from the tank. Inspect and clean the screen. Now, on the back side of the petcock is a square plate held on by four screws. Remove the screws and remove the plate. Underneath the plate you'll find a diaphragm. Hold the diaphragm up to the a light and gently stretch it and look for holes. If you find a hole, you'll have to replace the diaphragm.

Look inside the petcock where the needle is for trash. At this point you should be able to blow back up through the petcock to check for obstructions. Reassemble petcock and reinstall in the tank.

I've seen these petcocks give a lot of trouble exactly like you're experiencing. I recommend that you replace the petcock with a manually operated petcock. The Pingle petcocks are very high quality units but a bit pricey. If you'd rather stick to an OEM type unit, purchase a petcock from the Harley shop for a 1995 or earlier model. This will be a manually operated petcock. Plug the vacuum hose that you'll no longer need. You'll have to get into the habit of turning the gas on and off whenever you get on or off the bike like the old timers did. But, they'll never let you down.

Now, remove the fuel cap. Wipe it down real well with a clean cloth. Now, make sure your friends are NOT around for this test or you'll never hear the end of it. Put the threaded end of the fuel cap up to your lips and try to **** and blow through the vent. If you cannot, the vent is bad and you're not getting gasoline to your carb due to a buildup of vacuum in the tank.

Good Luck
Steve

It may indeed be out of gas. You can have a full tank of fuel and be "out of gas" in the carb. The culprit could be the vacuum operated petcock. The petcock has a diaphragm in it that is opened by engine vacuum. If that diaphragm is not functioning as it should, no gasoline gets to the carb.

To test the petcock, reach around behind it and feel for a small vacuum hose. Unplug this hose and replace it with a hose you can **** on. Using your mouth, **** on the hose with the fuel line disconnected. You should see fuel flow out of the petcock. If not, you must drain the tank by loosening the petcock and allowing the fuel to run out of the loose petcock. Use a large funnel and an empty fuel container to catch the fuel. Once the fuel tank is empty, remove the petcock. Take the plate on the back of the petcock off by removing the four small screws. You'll find a diaphragm, a small spring, and a needle. Hold the diaphragm up to the light and stretch it gently. If you find a hole in the diaphragm, replace it. Check the petcock for obstructions by blowing through it. Reassemble the petcock and test it again.

Check the hose that supplies the vacuum to the petcock. It comes from the backside of the carb and runs upwards to the VOES switch and then reduces in size and goes to the petcock. Make sure it's connected and has no holes or cracks in it.

If everything looks alright, replace the petcock, connect the hose and try to start your bike again.

These petcocks are notorious for giving problems. I always recommend that the vacuum operated petcock be replaced with a high quality manually operated petcock such as a Pingle. They're expensive and require you to manually turn the gas off like the "old school bikers" do but they won't leave you stranded out of gas with a full tank of fuel.

Good Luck
Steve

I think your fuel petcock has the newer vacuum operated petcock. If it does, it will have a small vacuum hose connected to the rear of the petcock. Whenever the engine is off, there is no vacuum on the line and the petcock shuts off the fuel automatically.

If your petcock is the manual version, it should be marked where to put the lever to turn the fuel off.

Sounds like you've got a vacuum leak somewhere. Either your intake seals or the carb seal is leaking air. Have you replaced the air filter housing? On the Evolution and later engines, the carb is designed as a "spigot seal" type carb. In other words, it just pushes into a seal instead of bolting on like the older carbs did. This means that the carb has to be aligned correctly or an air leak can occur around the seal. The air filter assembly is what holds the carb. into the seal and aligns the carb.

If you haven't messed with the air filter assembly there is one other thing that I've seen cause this problem. Your bike has two vacuum operated devices on it. One is the VOES switch and the other is the fuel petcock. The VOES switch is part of th igniton system and the petcock is the fuel valve on the fuel tank. The vacuum comes from either the carb or the intake manifold and is routed to the devices by a vacuum hose. Make sure this hose in connected to all three locations and has no holes in it. The vacuum hose to the petcock is on the backside of the petcock and the VOES is located on the bottom of the frame top tube under the fuel tank near the carb.

I have seen the vacuum operated petcock cause a vacuum leak in at least one occasion. Normally, when they go bad they just shut the fuel off to the carb and the engine won't run. But, I did have one that caused a severe vacuum leak and the bike acted exactly like you're describing. I took the petcock out of the tank. Drain the fuel first, not easy to do with the petcock being vacuum operated. I got a large funnel and held it under the petcock while I slowly unscrewed it. Once you have the petcock out, you'll see four small screws on the back side of it where the vacuum hose connects. Remove the screws and check the diagraphm behind the plate. Be careful, there is a small spring behind the plate. Take the petcock apart carefully so you can remember how to properly reassemble it.

Personally, I would eliminate the vacuum operated petcock and replace it with a high quality manual operated petcock. Like I said earlier, if they malfunction they usually shut the fuel off to the engine. There you are, a full tank of fuel but none to the engine. I'd replace it with an original Harley unit for a 1995 or earlier bike or a high quality aftermarket unit like a Pingle.

You need to find this problem before you ride the bike too much. The lean mixture resulting from a vacuum leak will cause the engine to run very hot.