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Will idle but dies with gas and LOUD clack from motor

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    #1

    Will idle but dies with gas and LOUD clack from motor

    Ill start with the clack. I have an 87 GS450l

    when i start it up it has a LOUD clack coming from what sounds like the heads. its kind of intermittent but it makes the sound more than it doesnt. I pulled the cam covers and couldnt find any abnormal signs of wear or binding or anything. It almost sounds like a cam lobe slapping on a lifter??

    The other thing, i can get the bike running and idleing sort of low. Full choke. But when i give it even the littlest amount of gas it dies. Even when its all heated up It wont stay running without the choke. The bike however isnt put together. I think the needle valves are operated by vaccuum? But the only thing hooked up to the carbs is a rigged water bottle with gas in it to feed the carbs. Ie. the gas tank isnt hooked up and neither are any of the vaccuum lines....soo maybe that would keep it from revving with throttle?

    does anyone have a vaccuum line diagram?

    Id like to get the clacking fixed first, because it definitley doesnt sound good and if it goes above idle something will probably break lol

    any input is greatly appreciated

    THANKS!
    Tags: None
    #2
    Put a piece of vac line on the vac nipple and then put a bolt in it to seal up that HUGE HUGE HUGE vac leak..did you get that hint??? Then get the valves adjusted and at that point see how she is. If it will idle and not stall, check the timing and sync the carbs. BUT FIRST..Tell us just what maintenace you have already done, if youve "done the carbs" how did you do them? Full tear down or the ever so hopeless sprayed them with carb spray? We need a good picture of whats done so we can give more accurate responses.
    MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
    1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

    NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


    I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

    Comment

      #3
      just picked it up a week ago non-running sitting for 2 years. pulled it apart drained out all the old gas. sprayed the carbs down and cleaned out the jets then put it back together. now im at where im at.

      is there no vaccuum diagram for these things? I DLd a general manual but it shows nothing about vaccuum lines.

      and it didnt look like there was any adjustment for the valves? I read something about shims. Is that how they are adjusted?

      Comment

        #4
        Yes you have to replace shim's to correct for the camshaft to valve clearances. The exact spec is in that manual you downloaded but its a common spec for all 2 valve per cylinder engines.

        You should read that whole manual, there is allot in there that will help you understand everything you need to know but there will be more people to answer your questions.

        As far as the vacuum diagram, its simple.

        You have 4 lines total coming from the carbs

        1 in the middle is your gas input

        2 you have two lines coming out of the middle on each side of the carbs. These are just Vent lines, let them hang.

        4 you have one line coming form one carb somewhere near the top front of the carb and this is the leak that chuck is talking about. Put a line on that one and plug the line. that should help everything.

        Its supposed to plug into the petcock on the tank. Its like an automatic ON/OFF for the gas that only turns on the gas when its running and turns it off when its not.

        The carbs need to be Dunked to clean them properly. That means completely disassembling them and dunking the bodies.
        Just spraying them is hopeless unfortunately.


        As far as the clack ?

        Can you post a video? or describe it better.

        hope this helps



        What do you mean by "isn't put together"?

        If you don't have the airbox on it will act just like that as well.

        these carbs need an airbox as a form of restriction to suck the throttle slides up and give you more gas.
        Last edited by Mekanix; 05-18-2012, 02:27 AM.
        Stephen.
        1981 GSX540L "Frankintwin"
        1989 GS500E Resto-mod .
        400 mod thread
        Photo's 1
        Photos 2
        Gs500 build thread
        GS twin wiki

        Comment

          #5
          When Cliff comes along read the carb rebuikd tutorial in his Megawelcome. Sorry to heap this on you, but those carbs are still junk untill you do a full tear down and replace all the Orings in them and on the fuel tee and transfer tubes. All that "clacking" I suspect is from the engine basically gasping and striving to get fuel and the cleaning and syncing will eliminate probably 99% of it. Theres no other way around it I am afraid to say. The internal passages are so full of corrosion and hardened old fuel they will never run right till properly soaked in Berrymns for at least 24 HRS per carb body. You can put 2 bodies in the can side by side. Dip all the jets, float seats, float needles for the same amount and poke each hole very well and rinse with carb spray and follow that with compressed air. Do the same rinse and air with the bodies as well. Youll be astounded at what change just that is gonna make for you.
          MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
          1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

          NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


          I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

          Comment

            #6
            yea there is no airbox currently on the bike. just open carbs. i know some people run pods and what not, so shouldnt it work regardless...to some extent? lol

            i guess ill have to do a full carb tear down then.

            The clacking is LOUD...i have no clue how carbs would cause that issue. Sounds like metal slapping metal

            Comment

              #7
              oh and also it increases with revs...so if the motor revs the clacking gets faster...like a super crazy exhaust leak i guess..but its not and exhaust leak

              Comment

                #8
                Originally posted by eviper21 View Post
                yea there is no airbox currently on the bike. just open carbs. i know some people run pods and what not, so shouldnt it work regardless...to some extent? lol

                Absolutely not with the factory tuning!

                There are some mods required to run pods. such as drilling out the slide and installing different main jets and air jets.

                That clack might be the one piston rocking back and forth while its doing all the work and dragging the other one along.
                Stephen.
                1981 GSX540L "Frankintwin"
                1989 GS500E Resto-mod .
                400 mod thread
                Photo's 1
                Photos 2
                Gs500 build thread
                GS twin wiki

                Comment

                  #9
                  Post a video with good volume..if its that LOUD then just maybe its a broke rod or bent one. Anyone know if thisbike has the twisted crank syndrome in its model history???
                  MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                  1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                  NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                  I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                  Comment

                    #10
                    Could the clacking be cam chain tension too loose? You've got no chance of sorting the running without setting the carbs up properly and with a filter, try putting a bit of cloth over each carb mouth with elastic bands or hose clips.

                    Comment

                      #11
                      Good point Evil...he can at least pull that and be sure the pushrod is freely moving..I think I would do that straight away!!! The more things that can be eliminated the better for sure. I did mention to check the timing before...so may I now amend that to say..Pull the cam cover and check the cam timing to be sure it hasnt jumped a tooth. Its as easy as 1, 2, 3. ( pun intended ).
                      MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                      1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                      NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                      I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

                      Comment

                        #12
                        Use a golf tee seals better.

                        Originally posted by chuck hahn View Post
                        Put a piece of vac line on the vac nipple and then put a bolt in it to seal up that HUGE HUGE HUGE vac leak..
                        sigpicMrBill Been a GSR member on and off since April 2002
                        1980 GS 750E Bought new in Feb of 1980
                        2015 CAN AM RTS


                        Stuff I've done to my bike:dancing: 1100E front end with new Sonic springs, 1100E swing arm conversion with new Progressive shocks installed, 530 sprockets/chain conversion, new SS brake lines, new brake pads. New SS fasteners through out. Rebuilt carbs, new EBC clutch springs and horn installed. New paint. Motor runs strong.

                        Comment

                          #13
                          Bikes with the CV carbs pretty much won't run with out the air box or some kind of air restriction. Had the air box off mine at one time doing some work on it and noticed it wouldn't run past 2,000 rpm and just bog down to the point of stalling. I put the airbox back on no problems.

                          Originally posted by eviper21 View Post
                          yea there is no airbox currently on the bike. just open carbs. i know some people run pods and what not, so shouldnt it work regardless...to some extent? lol

                          i guess ill have to do a full carb tear down then.

                          The clacking is LOUD...i have no clue how carbs would cause that issue. Sounds like metal slapping metal
                          sigpicMrBill Been a GSR member on and off since April 2002
                          1980 GS 750E Bought new in Feb of 1980
                          2015 CAN AM RTS


                          Stuff I've done to my bike:dancing: 1100E front end with new Sonic springs, 1100E swing arm conversion with new Progressive shocks installed, 530 sprockets/chain conversion, new SS brake lines, new brake pads. New SS fasteners through out. Rebuilt carbs, new EBC clutch springs and horn installed. New paint. Motor runs strong.

                          Comment

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