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    Fuel Valve (petcock) questions

    hello, new to this site and also new to just picking up a 1980 gs1000 L shafty , been trying to sort out a few issues with this bike and making some progress, here is what I have discovered, when i got this bike it came with a few spare parts, one was a used or the old take off petcock, the bike was runnig great and then it acted up and felt like it was running out of fuel , checked the lines from carb to petcock vacuum port , it was a new hose as well as the fuel line to carb tee , I decided to remove petcock and do a visual, what i found was that the all the parts where new and when I put a suction on vacuum port it pulled in the valve , great . upon further inspection under a magnifier is that there was a gooey piece of rubber substance lodged in the part of vacuum port that has the holes from which valve is pulled in, after thinking about this I think I know what the deal is, i believe it is a vacuum check valve that has deteriated over time , i think it is used to maintain a vacuum . this part is not supplied with any rebuild kit . the only way to fix this is to be able to replace just that piece that is screwed on with 4 little philips scews, i dont think you can buy that seperate , so my next step is to look into picking up an automotive inline vacuum check valve ............any thought or comments on this .........thanks.

    #2
    You're right about that being a check valve, and welcome to the site. Adding a external check valve is an interesting idea, please post a photo and/or link if you find a suitable (cheap) check valve.

    The 1980 petcock is a one year obomanation that was quickly replaced. It requires a pulse of vacuum to turn on the prime system which is unique to the line of GS petcocks, and I think that check valve is what holds the vacuum to keep the diapharam open after the pulse.

    Good luck
    Ed

    To measure is to know.

    Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

    Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

    Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

    KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

    Comment


      #3
      answer found after the fact (petcock)

      thanks for the welcome, just used the search feature again and found another member with same thinking on this issue, he went a step further and said without that check valve it turns the fuel valve (petcock) into a fuel pump, that puts that vacuum in check so to speak, all these people buying these rebuild kits only to find out they still have issues , that little rubber check valve turned into a black goo , guess it just stops that vacuum pulse and keeps the diaphram pressurized to stay open , kuddo's to Don for his input , I would like to post pics but im a bit challenged into resizing pics that way, darn it. Don did post some although they were very blurry. heading to the parts store for cheapo fix

      Comment


        #4
        I'd be tempted to get a new petcock all together and with a little luck, one for a 1981-83 might just fit. Money well spent if you can source a new one. Not sure on the automotive vac valve, where would you place it?

        Welcome to the fourm! BassCliff will be out and about later to give you the formal treatment.

        Comment


          #5
          it will be spliced into the vacuum line to petcock, very confident this is a real fix, those rebuild kits are great except this little check valve is not included and could not be installed anyways if it was..........a new petcock for $90 is nice but $4 is more to my liking

          Comment


            #6
            New petcocks are $45... http://cgi.ebay.com/ebaymotors/1980-...item2eac663075
            These parts are identical to the OE petcock, not cheap aftermarket junk.
            I still like your check valve idea but just saying...
            Ed

            To measure is to know.

            Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

            Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

            Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

            KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

            Comment


              #7
              yes i seen them on ebay, I looked at suzuki OEM parts list because I was leary about proper fitment, $45 is not bad at all , everything is new in my petcock except that one piece ...........its there for a reason, the bike does run but you can feel it flutter at certain RPM , I just restored 3 commercial mowers and the so call fuel pump was just a rubber gasket that pulsed. those tanks were not gravity fed like on our bikes , the fuel is pulled into the carb on those mowers . I had an issue similiar to this on my Harly Evo motor, the rocker boes had what they called umbrella valver to keep crankcase oil mist from getting out of the heads and into the air cleaner , they named these motors nose bleeders, it was all caused by these little cheapo check valves , they just deterioted over time with heat and petro , thanks for input, will let you know.........just hope i find someone at parts store that can find one

              Comment


                #8
                Send a photo when you "get er done". We're photo whores around here!

                Comment


                  #9
                  i hope i'm not too late with this information, but i was looking into possibly buying a new pet cock for my 81' gs 650 g, and found a fairly inexpensive place to get OEM parts, here is the part number for an 1980 gs 1000 GL, i think it should fit an "L" model also, someone correct me if i'm wrong but here is the part number and price, and web page link to order it online.


                  15
                  SKU: 44300-47270
                  COCK ASSY, FUEL Includes Item(s) 16 1 $64.43

                  Comment


                    #10
                    Greetings and Salutations!!

                    Hi Mr. bigdee,

                    You'll find lots of GS shafty lovin' on my website.

                    I just stopped by to welcome you to the forum in my own, special way.

                    If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

                    Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

                    Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

                    Thanks for joining us. Keep us informed.

                    Thank you for your indulgence,

                    BassCliff

                    Comment


                      #11
                      Originally posted by Nessism View Post
                      The 1980 petcock is a one year obomanation that was quickly replaced.
                      LOL Ed! Was that a Freudian slip? Shoud that be Obamanation?


                      Thank you for your indulgence,

                      BassCliff

                      Comment


                        #12
                        Originally posted by BassCliff View Post
                        LOL Ed! Was that a Freudian slip? Shoud that be Obamanation?


                        Thank you for your indulgence,

                        BassCliff
                        Sure...guy gets named the "man of the year" and he goes political on us.



                        Man...go figure!

                        Comment


                          #13
                          Thank You for the WELCOME , already checking out the info, lots of it

                          Comment


                            #14
                            well I installed the inline one way vacuum check valve, i did manage to find one but it was not at the local auto parts, they did have one but it was the wrong size for the vacuum hose, well i eventually found one at the local ford dealer , $10.67 it was also a dual port valve and had to block off one of them . i think it was used to operate the door on heater control mechanism, works like a champand holds that petcock open rock solid...........on to the next issue

                            Comment

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