Author Topic: Fuel Vacuum Problem (Read 12619 times)

mguyver · « **on:** July 25, 2005, 12:07:14 PM »

Hello Everyone,
I have a problem with the Fuel vaccum or maybe it's something else. The Starter kicks fine, the battery is fine but there's no fuel goes in the caburators, I have put in a new petcock, tried it on ON, PRI and still fuel does not get in. When i disconnect the fuel line from petcock, the fuel within the line goes down to carburators and the bike starts fine and it will work until the line is out of fuel. I reconnect the line and again no fuel goes in. I have checked the fuel line and they are all clean.
I have contacted the Suzuki dealer but they do not help me and demand to take the bike in for service. Any ideas? how would i be able to fix the vacuum issue?
Thanks,

PeteSC · « **Reply #1 on:** July 25, 2005, 12:15:26 PM »

You don't have any of the hoses hooked up wrong?

Maniac · « **Reply #2 on:** July 25, 2005, 01:43:50 PM »

Fuel won't flow until you disconnect the line?

Sounds like you have a vent thats clogged up somewhere. Try the petcock in the 'prime' position with the fuel cap open.

PitterB4 · « **Reply #3 on:** July 25, 2005, 02:37:40 PM »

Quote from: "Maniac"

Fuel won't flow until you disconnect the line?

Sounds like you have a vent thats clogged up somewhere. Try the petcock in the 'prime' position with the fuel cap open.

My thought exactly.

mguyver · « **Reply #4 on:** July 25, 2005, 03:00:45 PM »

Thank you all for your replies. The fuel lines are all connected correctly and i double checked the the user mannual. I tried placing the petcock on PRI position with tank cap open, no luck. I even tried to disconnect the vacuum line from the carburator, no luck either. Any other suggestions? Does anyone know if this bike has a fuel pump? The user manual does not mention anything about it.

Maniac · « **Reply #5 on:** July 25, 2005, 03:18:57 PM »

Which series of bandit is it?

I don't believe any of them have a fuel pump, but I could be wrong. What are the labelings on your petcock? PRI and RES or PRI, ON, RES?

If it's just PRI and RES then these are Primary and Reserve, not Prime. This is how the stock Bandit 400 is, there is a little screw on the faceplate of our petcock that needs to be removed before we can turn it to Prime.

mguyver · « **Reply #6 on:** July 26, 2005, 10:17:38 AM »

It's a 1996 Bandit GFS 600. The labling on the petcock faceplate marked as RES, PRI, ON and i figured there might not be a fuel pump since i've been looking all over and no signs of it. When i had the petcock off the tank, the gas line was open in any position and i could blow through it. On the other hand the vacuum line was closed. Is that how it suppose to be?
Thanks,

regaliz2 · « **Reply #7 on:** July 26, 2005, 01:05:30 PM »

There is no fuel pump in the bandit, I think that the problem comes from a a faulty valve, otherway could be a clog hose like have been said but if you have check with the cap open that leave this out.

Good luck

mguyver · « **Reply #8 on:** July 26, 2005, 03:11:58 PM »

My thoughts exactly, i might have to check the valves.
Thank you all for your helpful responses.

Silverstreak · « **Reply #9 on:** July 27, 2005, 06:12:12 PM »

I'm not a mechanic so I can't speak to this with much authority but I recently had a problem that sounds similar. I had a vacuum leak on a hose that runs between the carbs and the tank. My mechanic told me that when the vaccum is sufficient it opens the fuel line from the tank. Mine had a leak at a T connection. I'm not sure what purpose the T serves but it had a rubber cap on it and the cap was cracked.

Check your rubber, maybe it has a hole in it.

Red01 · « **Reply #10 on:** July 30, 2005, 01:31:51 PM »

With the fuel line disconnected, does fuel flow from the tank when the petcock is in PRI?

PRI is not vacuum controlled, so it should flow freely. If it doesn't, it's either a tank vent problem or a petcock/filter problem.

mguyver · « **Reply #11 on:** August 01, 2005, 12:51:56 PM »

Silverstreak,
i have only one vacuum line going from the petcock to carb #4 and there's no T line. i checked that line and no cracks. i even disconnected the Vacuum hose and still nothing.

Red01,
yes if i disconnect the gas line and place the petcock on PRI, the gas pures out freely. i even took out the fuel filter and made a direct connection for the tank to the carb, no hope.
The plugs spark very nicely but they are completely dry and no gas gets in.

Maniac · « **Reply #12 on:** August 01, 2005, 02:07:20 PM »

Have you tried sticking a vacuum gauge on the petcock end of that vacuum line?

chippi · « **Reply #13 on:** August 01, 2005, 03:39:41 PM »

Quote from: "Silverstreak"

I'm not sure what purpose the T serves but it had a rubber cap on it and the cap was cracked.

If someone did a PAIR modification/removal that T- is blocked off

todius · « **Reply #14 on:** August 01, 2005, 06:26:17 PM »

Pull the vacuum hose to the petcock off the end that goes to the carbs/intake. Put the petcock into ON or RES (if gas is low) position and suck on the vacuum line (be careful.. if the petcock's diaphragm is torn, gas may come through that line... it shouldn't). You should hear the petock activate and gas should start flowing. If it doesn't, you've got a clogged line/petock/vent etc, or the diaphragm on the petock is bad.