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1981 GS550L Fuel Valve

  • Thread starter Thread starter tarch
  • Start date Start date
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tarch

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I have a 1981 GS550L and I am having trouble starting. Was running fine But I was cleaning it last night and I took off the gas tank. When I did so I put the fuel valve on RES. Then I went for a ride and absentmindly left it on reserve. I bogged down and had to stop. The tank is full of gas. Now I can't get it started. I don't know which position the valve is it be set. I don't have an "ON" position. I only have "FULL", "RES", and "PRI" positions. What position is to be set when riding. Could I have flooded the bike and that is why I can't get it running now? I tried all the positions. However, I have only had the bike for a month now and I am a novice when it comes to mechanics. Any onther Bike I have seen has "RES", "ON", and "OFF" positions. I am confused and I don't have an owners manual. Does anyone know how I can get an owners manual for a 1981 GS550L?
 
I don't want to insult your intelligence, but here goes. You don't have an "Off" position. The valve is vacuum actuated so its "Off" when the engine isn't running. The "Full" or "On" position is the setting to use after you've filled the tank. Leave it there until it begins to sputter or lose power. You've reached the reserve position and need to set it to "Res" to allow the remaining gas to flow till the carbs while you find a gas station. If the bike has sat for a while the gas in the carb bowls or resoivoirs could have evaporated. Turn it to prime so that gas can flow to the carbs without the engine vacuum being present to open the valve. Wait about a minute for the carbs to refill, start the bike and return it to the "Full" position or the "Res" if necessary.

I don't know your bike but based on the settings on the valve you have a vacuum actuated petcock. There are two hoses that connect to it. One is probably bigger than the other. The smaller hose will go from the valve to a barb on one of the carbs that is very near the head. The larger hose will go to the carb. Go to http://houseofmotorcycles.bikebandi...el_dept_id~988020~model_dept_name~GS550LX.asp. Hose 78 goes to the smaller barb on the valve and 80 goes to the larger one. Both hoses must be installed and not leaking to get the bike to run.

Before you put the tank back on turn the valve to "Pri". Be prepared to catch the gas that will run out. When you do this gas will run out of the fuel line barb. Return the valve to "Res" or "Full" and reinstall the tank and both hoses. Turn the valve to "Pri" and then wait a minute and try to start the bike.

When the tank is removed you expose some wiring. Check them all to make sure you haven't pulled anything loose.

LOL
 
Thanks

Thanks

Thanks....I beleive this will help. I know I had to put two hoses back on when I put the tank back on. One to the Carb that came off the back of the positions valve (That I found out today was also pinched off) and the other one came from the right that goes on a clear plastic "?something?" (what looks like a filter). This must be the "PRI" or Primer position hose. Is it possible to have a full tank of gas, run the bike on reserve, and run out of gas from the reserve, but still have a full tank of gas. I think this is what I did. Then I think I put the bike on PRIME instead of FULL and flooded the bike. Does this sound possible. The Bike has now been sitting all day in the Full position. Do you think it will start now? Do you think it's possible I have a vaccume hose off? Where would I look to make sure everything is in tack as it sould be?
 
You have two lines: a fuel line and a vacuume line. The fuel line is the fatter of the two. Fuel line runs from a T fitting between the carbs up to the petcock; vacuume line runs from a nipple on the front of the carbs up to the petcock. Check the following links for more info.
http://thegsresources.com/images/carbs/004_Vacuum Port to Petcock.jpg

http://thegsresources.com/images/carbs/003_T1_2 VENT.jpg

My guess is that you have a problem with one of these lines. Make sure they are right, turn to prime to fill the float bowls, turn back to ON, and start the beast!
 
Okay tarch,
No you cannot run out the reserve and still have gas in the tank. When in the "Full" position the bike will use gas that comes from a tube that is a couple of inches above the bottom of the tank. When in the "Res" position it will drain the tank completely. If you put it in "Pri" it will use all the fuel in the tank.

Again what you need to do is this. Make sure the hoses are not kinked or pinched. The small one goes to the carb near the engine. With the large on off the tank turn the valve to the "Pri" position to make sure fuel comes out of the tank. Have something clean on hand to catch the gas and pour it back in the tank. There needs to be a full flow, it can't be dripping or only filling half of the tube. If its flowing OK turn the valve back to "Res". The fuel flow must stop. Put the hose back on the tank and return the valve to "Pri". Wait 1 minute and try to start the bike. Let us know what you get.
 
tarch said:
Thanks....I beleive this will help. I know I had to put two hoses back on when I put the tank back on. One to the Carb that came off the back of the positions valve (That I found out today was also pinched off) and the other one came from the right that goes on a clear plastic "?something?" (what looks like a filter). This must be the "PRI" or Primer position hose. Is it possible to have a full tank of gas, run the bike on reserve, and run out of gas from the reserve, but still have a full tank of gas. I think this is what I did. Then I think I put the bike on PRIME instead of FULL and flooded the bike. Does this sound possible. The Bike has now been sitting all day in the Full position. Do you think it will start now? Do you think it's possible I have a vaccume hose off? Where would I look to make sure everything is in tack as it sould be?
Click to expand...

What happens if you try to start the bike? does it just click once and then nothing? if so you most likely flooded the engine (I've had this happen not too long ago). Check your spark plugs, are they wet? Also check where you fill the oil and smell if there's any gas. if so you will need to drain and replace your oil asap.

If your vaccum line works good (which on my bike it doesn't) you only need to use the RES or FULL/ON setting while riding or parked. The PRI is only used, as mentioned, to get gas into your carbs if you dont have a vaccum. PRI works on gravity, so since the gas tank is above fuel will constantly flow into the carbs. If you leave it on PRI while parked for too long, you will flood the carbs and then most likely the engine.
 
Last edited:
Thanks everyone

Thanks everyone

I am learning. It turns out that I had the bike on "PRI" and flooded the engine. after sitting for a while and setting the petcock to "FULL" the bike started up fine and I am riding and having a good time. Thank you everyone for your input. It really helped me out and tought a novis more about my bike. I am looking for an owner's manual for my bike. 1981 - 1982 GS550L. Any Ideas?
 
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