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    '77 GS750 issues

    alright, ive got a 77 gs750, and it was running great around town, but then...

    i went for a 40 mi ride, and about 3/4 the way threw, it died on me. i waited for a little while, and got it to start, but it drove for about 2 more miles, then died again. then it got started and went about 2 blocks.

    prior to these issues, it ran very well, pulled like no ones buisness... at this point, i can get it started and it will idol all day. but once i get going, it seems to flood out and bog real bad. i know im running a little rich, and to me it seems to be flooding.

    i have taken off the muffler, as i have been reading, might need to rejet, but my question is, why did it run very well for a while, then **** out?

    it is running rich, my plugs are black, that is another issue i know, but what im trying to figure out is why all the sudden it just crapped out?

    any help would be GREAT... thanks

    #2
    Originally posted by rightious View Post
    alright, ive got a 77 gs750, and it was running great around town, but then...

    i went for a 40 mi ride, and about 3/4 the way threw, it died on me. i waited for a little while, and got it to start, but it drove for about 2 more miles, then died again. then it got started and went about 2 blocks.

    prior to these issues, it ran very well, pulled like no ones buisness... at this point, i can get it started and it will idol all day. but once i get going, it seems to flood out and bog real bad. i know im running a little rich, and to me it seems to be flooding.

    i have taken off the muffler, as i have been reading, might need to rejet, but my question is, why did it run very well for a while, then **** out?

    it is running rich, my plugs are black, that is another issue i know, but what im trying to figure out is why all the sudden it just crapped out?

    any help would be GREAT... thanks

    Welcome !!

    We need a little more info. You say it was running great around town. How long was it running great ? Just one ride, or have you been riding it for years ?
    When did you take the muffler off and WHY ?!?! It ran very well and then you removed the muffler ??!!??!! WHY ?!?!?!

    You've really changed the way the bike bike breathes. They are very particular about the air/fuel mixture and the exhaust pressure.
    Larry D
    1980 GS450S
    1981 GS450S
    2003 Heritage Softtail

    Comment


      #3
      My first instinct is that the gas cap is plugged up and isn't venting. Thus you got too much vacuum built up in the tank after burning enough fuel and it starved. If it happens again try removing the gas cap and immediately re-starting it.

      You'll have to tell us the muffler story...

      Comment


        #4
        well, i took off the muffler for a few reasons

        1. loud pipes save lives.
        2. sounds better to me.

        i have been riding for only a few weeks, but the most i had gone was probably 5 mi. through those times, it ran and pulled, the muffler was off the whole time, it ran without it, that is not the issue.

        about the gas cap, if it was vapor locked, wouldnt that have a lean situation?

        Comment


          #5
          Originally posted by rightious View Post
          well, i took off the muffler for a few reasons

          1. loud pipes save lives.
          2. sounds better to me.

          i have been riding for only a few weeks, but the most i had gone was probably 5 mi. through those times, it ran and pulled, the muffler was off the whole time, it ran without it, that is not the issue.

          about the gas cap, if it was vapor locked, wouldnt that have a lean situation?
          Did you check for an airflow restriction (air cleaner)? Is your breather inlet clear?

          Put the mufflers back on loud pipes don't save lives they just make it harder to hear ANYTHING but your motor and that includes you. You won't hear the horns or sirens, etc and it may result in dire consequences for you. Not to mention you're pi$$ing everyone else off...and yes you SHOULD care.

          Comment


            #6
            Originally posted by Rudeman View Post
            Did you check for an airflow restriction (air cleaner)? Is your breather inlet clear?

            Put the mufflers back on loud pipes don't save lives they just make it harder to hear ANYTHING but your motor and that includes you. You won't hear the horns or sirens, etc and it may result in dire consequences for you. Not to mention you're pi$$ing everyone else off...and yes you SHOULD care.
            that is what i thought about originally, being that the air filter is dirty (need to find a local shop to buy parts), so i took off the side of the air box while i was stranded on the road, to allow air to freey flow into the carbs temp. that did not help. i am going to buy a new filter asap, but my thinking is i ruled out that problem.

            my main question is it was running great up until 1 point. now i can not get it to go more than a block without bogging out

            Comment


              #7
              Originally posted by rightious View Post
              alright, ive got a 77 gs750, and it was running great around town, but then...

              i went for a 40 mi ride, and about 3/4 the way threw, it died on me. i waited for a little while, and got it to start, but it drove for about 2 more miles, then died again. then it got started and went about 2 blocks.

              prior to these issues, it ran very well, pulled like no ones buisness... at this point, i can get it started and it will idol all day. but once i get going, it seems to flood out and bog real bad. i know im running a little rich, and to me it seems to be flooding.

              i have taken off the muffler, as i have been reading, might need to rejet, but my question is, why did it run very well for a while, then **** out?

              it is running rich, my plugs are black, that is another issue i know, but what im trying to figure out is why all the sudden it just crapped out?

              any help would be GREAT... thanks
              ok so here we go lets start with
              what maintenance have you done to this bike ther are some basics that you need to do
              1 adjust the valves
              2 clean the carbs this means dip em and put new o-rings in and set them back to factory settings (if your bike is stock IE: no pods no aftermatket pipe)
              3 check and set the timing and also check the points for wear
              4 vacum sync the carbs

              once these things are done then you can start to sort out what is happening with it quitting on a long ride
              you said it's running rich have you pulled the plugs and looked at them (posting a pic of the plugs would be good )
              and yes you can have a rich condition and have a vapor lock
              removing the side cover from your air box will indeed produce a lean condition by letting in more air but with a dirty filter your not accomplishing much (change the filter) you haven't ruled out that problem yet a pluged filter will no matter if the side cover is on or off not let the air flow

              as for loud pipes well it's been in my experience that a louder pipe will make cagers look around for you but make it too loud and it just upsets them not to mention it upsets your neighbors as well
              find a good pipe that is not too loud and put it on
              and with these bike it is best to have a muffler
              just because the it ran with the muffler off doesn't mean it's not contributing to the problem

              if you think it's flooding then that would point to a float height problem so thus performing setp 2 would be a good place to start but before you put the carbs back on after cleaning them perform step 1 then run the bike and then move onto steps 3 & 4 once those things are accomplished and you know there set right then you can start to look elsewhere for your problem it could be that you have a dirty fuel filter as well there are a number of things that it could be
              start with the steps that i have laid out for you and go from there
              and more info about the bike and some pics of the plugs and bike would be good and help us to help you

              Comment


                #8
                SPYDERMAN -
                "removing the side cover from your air box will indeed produce a lean condition by letting in more air but with a dirty filter your not accomplishing much (change the filter) you haven't ruled out that problem yet a pluged filter will no matter if the side cover is on or off not let the air flow"


                well sir, when i took the side of the air box off, it bypassed the filter and ran straight into the carbs(i know its bad, but i wanted to get home).
                so i think that i did rule out the filter. im going to change it, but i can't see spending $50 on the stock air cleaner. so im giong to get pods, which i know i need rejetting, and im not positive where to start. like i said i have 4 - 1 exhaust right now, no muffler, and i want pod filters...

                i would love someone to tell me where to start.

                thanks again for all your ideas

                Comment


                  #9
                  where to start.... before you start changing stuff that directly contributes to bad running if not setup correctly, get it running correctly FIRST then make changes. what does the filter loook like... is it clean or grubby looking? can u use an air hose to blow it out if dirty.... if it's cleanish looking chances are it's not yer problem.

                  if you've only ridden it for approx 5 miles the entire time you've had it chances are it never properly warmed up and the ride you went for where you experienced iussues it was nicely warmed up.... that would point to a fuel problem as per the crap running, black plugs and it cutting out..... way over rich. pop the carbs out and clean em properly along with a set of o-rings.

                  that's a good place to start.... let us know who ya get on after thats done

                  Comment


                    #10
                    Originally posted by rightious View Post
                    SPYDERMAN -
                    "removing the side cover from your air box will indeed produce a lean condition by letting in more air but with a dirty filter your not accomplishing much (change the filter) you haven't ruled out that problem yet a pluged filter will no matter if the side cover is on or off not let the air flow"


                    well sir, when i took the side of the air box off, it bypassed the filter and ran straight into the carbs(i know its bad, but i wanted to get home).
                    so i think that i did rule out the filter. im going to change it, but i can't see spending $50 on the stock air cleaner. so im giong to get pods, which i know i need rejetting, and im not positive where to start. like i said i have 4 - 1 exhaust right now, no muffler, and i want pod filters...

                    i would love someone to tell me where to start.

                    thanks again for all your ideas
                    ok i understand wanting to get home not a problem there
                    however i have a 77 50 right now as well as having owned 2 others in the past and know for a fact that unless you took the filter out as well as taking the side cover off then you didn't bypass the filter any how not going to argue with you about this it's just not worth it
                    what you do need to understand is that myself as well as other have out lined what you should start with then once you have the problem solved then you can move on but if you try and make changes right now it's only going to make things worse for you to sort out
                    you need to do the steps as outlined for you as well as checking the fuel flow to the carbs once there cleaned if that solves the problem then move onto putting on the pods and rejetting
                    get it running right first then do the pods because if you do it now you won't be able to jet the carbs correctly no matter how hard you try
                    also by cleaning the carbs you will then be able to tell us what jets you have in it and the position of the clip on the jet needle and then we can point you in the direction of where you need to go to jet it correctly
                    are you seeing what i am saying to you now i hope so because it will make it easier and take less time to get it sorted if you do

                    Comment


                      #11
                      Originally posted by Spyderman View Post
                      ok i understand wanting to get home not a problem there
                      however i have a 77 50 right now as well as having owned 2 others in the past and know for a fact that unless you took the filter out as well as taking the side cover off then you didn't bypass the filter any how not going to argue with you about this it's just not worth it
                      what you do need to understand is that myself as well as other have out lined what you should start with then once you have the problem solved then you can move on but if you try and make changes right now it's only going to make things worse for you to sort out
                      you need to do the steps as outlined for you as well as checking the fuel flow to the carbs once there cleaned if that solves the problem then move onto putting on the pods and rejetting
                      get it running right first then do the pods because if you do it now you won't be able to jet the carbs correctly no matter how hard you try
                      also by cleaning the carbs you will then be able to tell us what jets you have in it and the position of the clip on the jet needle and then we can point you in the direction of where you need to go to jet it correctly
                      are you seeing what i am saying to you now i hope so because it will make it easier and take less time to get it sorted if you do
                      yes sir, what do you think is the best way to get around buying a new $50 stock air filter in order to get it running right without changing anything?

                      if i put on the air box on withoutthe filter, will that help? or is that the same as no air box?

                      thanks again, and spyder, dont mean to argue, just trying to understand

                      Comment


                        #12
                        what is it and your fixation with bypassing/removing the air filter.... CLEAN THE CARBS and see what happens.

                        Comment


                          #13
                          Originally posted by rightious View Post
                          yes sir, what do you think is the best way to get around buying a new $50 stock air filter in order to get it running right without changing anything?

                          if i put on the air box on without the filter, will that help? or is that the same as no air box?

                          thanks again, and spyder, dont mean to argue, just trying to understand
                          ok no problem i hope that i explained it a little better then so that you do understand what i was getting at
                          so just how dirty is the air filter and is it the stock paper one ?
                          as suggested by someone else here can you use some compressed air to blow the filter out to get it somewhat clean (not too much pressure though don't wanna blow a hole in it ) is this doable for you ??

                          if the filter is that dirty then using the air-box with no filter will be better but there is the chance that you'll still get a lean condition problem is that until you try you won't know and you won't know how lean of a condition you'll get till you try kinda a catch 22 i think at this point try the air box without the filter and see if it'll behave better

                          have you looked at the plugs do you know for sure that it's rich?
                          have you checked the fuel flow

                          i had an issue with my bike earlier this summer where when i put my new exhaust can on that it was breathing so much better that it would suck the float bowls dry at anything over 3/4 throttle i had to go to a 3/8 fuel line and a high flow fuel filter to solve the problem

                          so this is another area that you can look at you may have created the same situation as i had by taking off the muffler
                          honestly try putting the muffler back on and see if that cures the problem if it does then you know that you need to give it more fuel flow and then if i were you i would spend the time and do the steps mentioned and then put the pods on and a good pipe the Vance & Hines pipe is nice has a really nice tone and look good then rejet it for the pods and pipe
                          it is better to have some type of muffler on it to tone it down a bit and help the engine out
                          not to mention keeping the police from ticketing you every-time they see you

                          Comment


                            #14
                            Originally posted by Spyderman View Post
                            ok no problem i hope that i explained it a little better then so that you do understand what i was getting at
                            so just how dirty is the air filter and is it the stock paper one ?
                            as suggested by someone else here can you use some compressed air to blow the filter out to get it somewhat clean (not too much pressure though don't wanna blow a hole in it ) is this doable for you ??

                            if the filter is that dirty then using the air-box with no filter will be better but there is the chance that you'll still get a lean condition problem is that until you try you won't know and you won't know how lean of a condition you'll get till you try kinda a catch 22 i think at this point try the air box without the filter and see if it'll behave better

                            have you looked at the plugs do you know for sure that it's rich?
                            have you checked the fuel flow

                            i had an issue with my bike earlier this summer where when i put my new exhaust can on that it was breathing so much better that it would suck the float bowls dry at anything over 3/4 throttle i had to go to a 3/8 fuel line and a high flow fuel filter to solve the problem

                            so this is another area that you can look at you may have created the same situation as i had by taking off the muffler
                            honestly try putting the muffler back on and see if that cures the problem if it does then you know that you need to give it more fuel flow and then if i were you i would spend the time and do the steps mentioned and then put the pods on and a good pipe the Vance & Hines pipe is nice has a really nice tone and look good then rejet it for the pods and pipe
                            it is better to have some type of muffler on it to tone it down a bit and help the engine out
                            not to mention keeping the police from ticketing you every-time they see you

                            ALRIGHT! now thats the kind answer i was looking for.

                            i will defenatly try those steps, the plugs are coal black, so i know i am rich, i just got new plugs, and tryed to clean the filter (its foam over paper) but its pretty damn dirty. so i will try air box - filter. i'll let you know how it goes, thanks again man...

                            Comment


                              #15
                              well, i put the airbox, and muffler back on to no avail. it is acting the same way, so i pulled the carbs off and now am tearing into them. nervous, but hopfully it will help.
                              the situation is that it is definitely rich. when i pulled the carbs off the rubber mounts off the motor, it was soaking wet with gas. i just had it running, so that was the sign that it has waaaay too much fuel.
                              when i crack the throttle, if it doesnt bog out, then it has a black plume of smoke that comes out. i can get it not to bog by slowly bringing the rpms up to about 2500, then crack it wide open. if i just crack it open from idle, it bogs out. the floats look good, i dont know that much about rebuilding carbs, so i dont know if the needle valves great or not... they all look the same and seem to close when the float hits it.

                              help??

                              Comment

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