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Deceleration, well that's not in her vocabulary

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    #1

    Deceleration, well that's not in her vocabulary

    So As of late my bike has had this problem that when I release the throttle while riding and pull in the clutch she just keeps on going as if I never released the throttle in the first place. I've found that if I leave it in gear and bog down the engine with the brakes and then pull the clutch she'll finally go back to idle speeds again.

    Now my first thought was a stuck throttle cable, however I placed my hand on the throttle cable (where it mounts to the carb) and felt when I left off the handle if it lagged behind or got stuck. But it didn't. It's just loosen right up exactly when I'd release the throttle. So I don't believe this is my problem.

    It was suggested that it could possibly be stuck slides. But the last several times I've had them out i always ran my hand over them and checked for any burs that might cause it to get caught up on something, and every time they were smooth. Should I have oiled the slides before reinstalling them? Does this sound like slides sticking?

    I just don't understand how to justify that bogging down the engine would cause the slides to stop sticking. Oh also on a side note I painted the carbs to match the engine, could some of the paint be causing the problem?
    Tags: None
    #2
    Check that the butterflys are working smoothly. The throttle cable may be free but perhaps the butterfly valve is sticking??

    Don't oil the slides, that WOULD make them stick.
    '85 GS550L - SOLD
    '85 GS550E - SOLD
    '82 GS650GL - SOLD
    '81 GS750L - SOLD
    '82 GS850GL - trusty steed
    '80 GS1100L - son's project bike
    '82 GS1100G - SOLD
    '81 GS1100E - Big Red (daily rider)

    Comment

      #3
      Hi,

      Have you taken a close look at the carb diaphragms? Tears or pinholes are not good.


      Thank you for your indulgence,

      BassCliff

      Comment

        #4
        This probably belongs in your previous post ,but..... You mentioned a "tsunami" of fuel leaking when you rocked bike back and forth. If this bike has fuel gauge with a float inside tank, then fuel could be leaking out this float assembly- it would come down overflow hose ( if it still has one) or just spill out.
        If this bike has cv carbs, you can't have any intake air leaks or rpms will hang; also rpms might hang if just one of your throttle plates was misadjusted and not closing enough when you backed off throttle.Pulling in clutch removes load, so it doesn't take much to boost revs. Do you have the stock air cleaner assembly?
        1981 gs650L

        "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

        Comment

          #5
          Yep have checked and rechecked the diaphragms for holes every time I was in there through that whole re-jetting process. So I don't believe holes is a problem, however i'm not opposed to looking again, so I'll do that after finishing up some more class work. I'll also pull the seat and tank and finger around the butterfly valves a little to make sure they're moving without any impairment. Also just to clarify the butterfly are the valves that the springs and the sync screws are connected to correct?

          Anyways I'll do those checks and report back

          Comment

            #6
            Originally posted by tom203 View Post
            This probably belongs in your previous post ,but..... You mentioned a "tsunami" of fuel leaking when you rocked bike back and forth. If this bike has fuel gauge with a float inside tank, then fuel could be leaking out this float assembly- it would come down overflow hose ( if it still has one) or just spill out.
            If this bike has cv carbs, you can't have any intake air leaks or rpms will hang; also rpms might hang if just one of your throttle plates was misadjusted and not closing enough when you backed off throttle.Pulling in clutch removes load, so it doesn't take much to boost revs. Do you have the stock air cleaner assembly?
            Sorry for the double post but I just saw your post tom before I got offline. The fuel leakage was coming from the airbox hose which I should have mentioned even though I didn't. But it does have a fuel gauge assembly in the tank just the wiring is gone for the fuel gauge to be connected to the tank, and I just haven't traced the wiring yet to get it hooked up. Honestly however the bike get's ~50mpg even running poorly so I just keep an eye on that odometer.

            As for the airleaks I'll test this also when i'm out there. What's your preferred method? I've heard of spraying flammable liquids however I've also heard this to be unreliable. Also about the throttle plates, this term seems new to me where are they located? are they the same as the butterfly's?

            Comment

              #7
              Not that you need to know this useless info, but....In the good old days, when you looked down the throat of a two barrel carb or a four barrel carb, you'd see a pair of throttle plates linked together, similar to a flat butterfly wing set. In a single barrel carb, there's no butterfly wing shape- it's just a throttle plate to me!
              1981 gs650L

              "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

              Comment

                #8
                Well thank you for the response! So I attempted to check for air leaks by getting the bike to idle and then spraying break cleaner on the intake boots that go airbox-to-carb and carb-to-engine. There was no change in idle, not that I expected there to be but it couldn't have hurt to try. I then Pulled the carbs, and inspected the intake boots between the engine and carbs to find these nice little guys:


                You can see they go pretty far down, and are pretty deep...


                So would cracks like these cause air leaks!? Haha, I think they took their last drive today before getting replaced. Also would air leaks even tiny ones cause the rpms to hang? I'm also planning on ordering a set of o-rings from Mr. Robert at cycleorings.com. I figure even though the set i have in there now are possibly working a new set could only be better. Especially if it's a set everyone has had the best success with.

                As for the throttle plates, Honestly i don't know how those get put in wrong but they look screwed in tight, also they snap "closed" without any problems. The reason for the quotes around closed is that they don't totally close 100% around the throat of the carb. At the bottom of the plate there's a tiny little gap on all 4 carbs. Now I figured this was the idle air that needed to get though and was adjusted when you sync the carbs. Are they supposed to be 100% closed?

                Thanks again for your input!

                Comment

                  #9
                  When you adjust the idle screw it opens the throttle plates so that is normal. I would say you found your problem as a vacuum leak will do just as you described and the boots are leaking. Good luck

                  Comment

                    #10
                    Originally posted by Kapoor View Post
                    As for the throttle plates, Honestly i don't know how those get put in wrong but they look screwed in tight, also they snap "closed" without any problems. The reason for the quotes around closed is that they don't totally close 100% around the throat of the carb. At the bottom of the plate there's a tiny little gap on all 4 carbs. Now I figured this was the idle air that needed to get though and was adjusted when you sync the carbs. Are they supposed to be 100% closed?

                    Thanks again for your input!
                    If you can hear them snap closed, then I would think they're not
                    sticking...

                    No, they don't shut completely - as you indicated, the gap allows a wee bit of air through for the idle.
                    '85 GS550L - SOLD
                    '85 GS550E - SOLD
                    '82 GS650GL - SOLD
                    '81 GS750L - SOLD
                    '82 GS850GL - trusty steed
                    '80 GS1100L - son's project bike
                    '82 GS1100G - SOLD
                    '81 GS1100E - Big Red (daily rider)

                    Comment

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