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'77 GS750 was running, now isn't.

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    '77 GS750 was running, now isn't.

    I picked up a GS750 awhile back for very cheap. It has no body parts, just a roller with an engine. It sat in the corner for awhile, until the other day I decided to see if it ran. Hooked the coils up, cleaned the points...and much to my amazement...about 7-8 kicks and it fired up...not running great, but it was running. It was fine on idle, but when I tried to throttle up..it bogged. So, I pulled the carbs off...did a rough cleaning with spray carb cleaner and compressed air. Cleaned all the jets out (of which where pretty clogged..i'm surprised it ran as well as it did.) Re-assembled, put them back on the bike, then proceeded to make sure all of the mixture screws were at about the same position...carb 1...about 1 3/4 out...carb 2, same...carb 3, same...now the mixture screw on carb 4 is all jacked up. The top of it has been stripped out, so I take a small straight screwdrive and try to hammer it down into the head of the mixture screw a little, hoping to turn it out. No luck....I tried several different things until the only option I had left was to drill it out. So, I drilled. Since I ended up drilling the threads out as well, I re-tapped the carb body and re-threaded a new mixture screw (I had an extra) to match the new tap in the carb body. Cleaned out the carb body from drilling as best as I could with carb cleaner. Put the rack of carbs back on the bike..and no go. It won't start now. So..my only guess is that there are shavings down in the hole where the mixture screw goes, throwing the mixture completely out of whack and keeping it from starting. Any idea on how I can get them out? Thanks in advance.

    #2
    Welcome to the best fourm on the web! Bass Cliff will give you the formal "low-down" but for now, I'll offer a little advice on the carbs.

    You really need to soak those babies in a carb dip. The spray, usually does not work and you end up doing it right, in the end. There is a how to thread on just "how to" do it correctly. Rob Barr (cycleorings.com) will have what you need for the orings ect.

    As farr as the tap and shavings that you are concerned with...worry about them after/when you have things all apart and ready for the soak.
    It sounds like this is not your first trip around a bike, so this won't be anything too tough for you. You may want to start looking for a replacement carb/rack but to get it to run "good enough" for now, it sounds like your repair should work.

    Again...WELCOME to the GSR! A GREAT place with GREAT people....

    Dave

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      #3
      Nah..it ain't my first rodeo. I'm used to single carb though, and whenever I mess with multiple carbs, it always screws with me. I will probably pull the carbs apart tonight and soak them. I think at worst though, I could get by with a replacement for that single carb...if the shavings are down in there and I can't get them out. Plans are to soak them good, then try to blow them out best as possible with compressed air. Hoping for the best.

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        #4
        Originally posted by michaelbarry View Post
        Nah..it ain't my first rodeo. I'm used to single carb though, and whenever I mess with multiple carbs, it always screws with me. I will probably pull the carbs apart tonight and soak them. I think at worst though, I could get by with a replacement for that single carb...if the shavings are down in there and I can't get them out. Plans are to soak them good, then try to blow them out best as possible with compressed air. Hoping for the best.
        Which carbs are they?

        Most likely, someone around here will have a single for you.

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          #5
          Not sure what exact model...they're Mikuni (of course), slide, no accelerator pump or anything.

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            #6
            Tiz dis?

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              #7
              Yes, that would be them!

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                #8
                Greetings and Salutations!

                Hi Mr. michaelbarry,

                It's just me, the welcome wagon. Please click here for your mega-welcome, chock full of suggestions (like how to really clean those carbs), links to vendors and other information. Then feel free to visit my little BikeCliff website, where I've been collecting the wisdom this community so generously shares. Thanks for joining us, keep us informed.


                Thank you for your indulgence,

                BassCliff

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                  #9
                  So I pulled the carbs apart last night....have all the internals soaking in carb cleaner.....boiled the carb bodies in lemon juice...then cleaned them really good with water...they look great.


                  What are the chances of me getting the O-Rings I need at a hardware store..like Lowes?

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                    #10
                    o rings

                    you probably won't be able to get those o-rings at a hardware store...
                    Z-1 Enterprises will have them, Bikebandit or Mrcycles will also have 'em...

                    Comment


                      #11
                      Originally posted by michaelbarry View Post
                      So I pulled the carbs apart last night....have all the internals soaking in carb cleaner.....boiled the carb bodies in lemon juice...then cleaned them really good with water...they look great.


                      What are the chances of me getting the O-Rings I need at a hardware store..like Lowes?
                      Get them here.....http://cycleorings.com/

                      They must be made of nitrile so they can withstand the gas, just any o-ring will not do.
                      Larry D
                      1980 GS450S
                      1981 GS450S
                      2003 Heritage Softtail

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