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Newbie... With carburetor challenges

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  • #16
    I would definitely change all the fluids, especially the oil. If the petcocks and needle valves weren't working right you could have a crankcase full of gas, VERY common. After that, if it was me, I would try to fire it up if the carbs are set right. Before you put the carbs on, you need to bench synch them. Just set them all the same with the butterfly hole halved. I think you will find that in the tech tips. I guess you have checked your tank for rust inside. I would also use inline gas filters.
    Last edited by jjz28; 07-14-2013, 02:03 AM. Reason: added
    Jeff
    77 XS750 2D completely stock
    79 SF XS1100 "Picky" stock with harley mufflers

    Comment


    • #17
      Automatic Centre punch

      Sounds like a good bit of lateral thinking - maybe worth grinding down the tip so it is just under the pin diameter?
      I just bought an XS1100g with 11500 miles on it.
      It feels very flat, like its lean, just off idle, then at about 3 thou revs it gets going OK. diaphragm issue maybe?
      The classic bike dealer here in Oz told me his mechanic had overhauled the carbs so I asked for a rundown on what was done. Reading your thread makes me think it will be worth having a look and checking all the specs, float heights, emulsion tubes etc.
      Watch this space. I'm getting an Emgo vacuum gauge carb balancer to check the synching.
      Cheers
      Phil

      Here's the report:

      Service work done on XS Eleven was as follows

      - Remove and dismantle carburettors
      - Repair sticking slide on # 3 carburettor
      - Deglaze and clean slides
      - Clean all jets and float needles
      - Repair float mounting post on carburettor #3
      - Reassemble and tune carburettors
      - Check and clean air filter
      - Check compression ( 150 psi, all cylinders within 5 psi )
      - Balance carburettors
      - Change engine oil
      - Test ride
      80 G

      Comment


      • #18
        Originally posted by filthyphil View Post
        Sounds like a good bit of lateral thinking - maybe worth grinding down the tip so it is just under the pin diameter?
        I just bought an XS1100g with 11500 miles on it.
        It feels very flat, like its lean, just off idle, then at about 3 thou revs it gets going OK. diaphragm issue maybe?
        The classic bike dealer here in Oz told me his mechanic had overhauled the carbs so I asked for a rundown on what was done. Reading your thread makes me think it will be worth having a look and checking all the specs, float heights, emulsion tubes etc.
        Watch this space. I'm getting an Emgo vacuum gauge carb balancer to check the synching.
        Cheers
        Phil

        Here's the report:

        Service work done on XS Eleven was as follows

        - Remove and dismantle carburettors
        - Repair sticking slide on # 3 carburettor
        - Deglaze and clean slides
        - Clean all jets and float needles
        - Repair float mounting post on carburettor #3
        - Reassemble and tune carburettors
        - Check and clean air filter
        - Check compression ( 150 psi, all cylinders within 5 psi )
        - Balance carburettors
        - Change engine oil
        - Test ride


        You didn't say if you had the stock exhaust on it. If you don't, and your exhaust doesn't have a cross over pipe in it, you will get that 3500+ rpm surge.
        CZ

        Comment


        • #19
          So we were able to get the carbs back on it (nightmare...I assume some others agree!) and changed the oil. Cleaned out the tank which was stored well and fired it up!!!
          Lots of smoke, and a miss on number two or three but sure was a feeling of accomplishment to think that The project had 4 carburetors stripped to the bone just 1 day ago.
          Now I fear there's a top end job in the near future, but there was a lot of stuff sprayed into the plug holes to loosen things up, how long does it usually take to blow all that mess out?
          Thanks!
          1979 SF
          Rehabilitating a Well Loved Classic

          Comment


          • #20
            It will take a little bit. My bike has run rough with a cylinder down before. Just did it yesterday when warming it up in the morning. I don't know if it is a float hanging or what but I will turn off the petcock and rev it and then turn back on the gas and it will clear up. Don't do it very often. The gasket sometimes hangs the float but not sure if that is what is happening to me or not but yours may work its way out too. Did you do a compression test?
            Jeff
            77 XS750 2D completely stock
            79 SF XS1100 "Picky" stock with harley mufflers

            Comment


            • #21
              Quite often the rings will stick to the pistons and not float like they should after a sitting for a long time. It could take up to a couple hundred miles for them to completely release and be free again.

              As to a top end job. Run the bike for awhile before you get to involved in engine work.

              GO THROUGH THE ENTIRE BRAKE SYSTEM. Completely disassemble the master cylinders and clean them out. Completely disassemble the calipers and clean them out. Brake fluid absorbs water and that is bad for brake fluid. Just doing a brake bleed is not adaquate here, you need to do a cleaning. These bikes are more powerful than their braking system so you need to make sure the brake system is up to snuff before you go taking it out on the road.
              Nathan
              KD9ARL

              μολὼν λαβέ

              1978 XS1100E
              K&N Filter
              #45 pilot Jet, #137.5 Main Jet
              OEM Exhaust
              ATK Fork Brace
              LED Dash lights
              Ammeter, Oil Pressure, Oil Temp, and Volt Meters

              Green Monster Coils
              SS Brake Lines
              Vision 550 Auto Tensioner

              In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

              Theodore Roosevelt

              Comment


              • #22
                Originally posted by natemoen View Post
                Quite often the rings will stick to the pistons and not float like they should after a sitting for a long time. It could take up to a couple hundred miles for them to completely release and be free again.

                As to a top end job. Run the bike for awhile before you get to involved in engine work.

                GO THROUGH THE ENTIRE BRAKE SYSTEM. Completely disassemble the master cylinders and clean them out. Completely disassemble the calipers and clean them out. Brake fluid absorbs water and that is bad for brake fluid. Just doing a brake bleed is not adaquate here, you need to do a cleaning. These bikes are more powerful than their braking system so you need to make sure the brake system is up to snuff before you go taking it out on the road.
                +1 on what Nate said. Careful and thorough cleaning of brake system and you will probably not need new parts just clean out the crud that has built up and fresh brakefluid. Learn about the spooge hole so you will recognise it when you get there
                Phil
                1981 XS1100 H Venturer ( Addie)
                1983 XJ 650 Maxim
                2004 Kawasaki Concours. ( Black Bear)

                Comment


                • #23
                  I got sidetracked playing around with syncing carbs and checking compression, so I haven't made it to the brakes yet. Figured I don't need to worry about it stopping if it won't stay running!!
                  Engine is coming around really nicely, I had it all purring really well together today but I think I chased the carbs too far trying to get them perfect. I went the homemade vacuum gauge route so it's a bit tricky. Compression seemed good too, 2 topped out at 150, one at 140, and #2 is 130... Doubtful the gauge is accurate but given that it hadn't ran in 15 years or so I'd say good signs that nothing tragic is going on in there- thoughts?
                  1979 SF
                  Rehabilitating a Well Loved Classic

                  Comment


                  • #24
                    Originally posted by Zeston View Post
                    I got sidetracked playing around with syncing carbs and checking compression, so I haven't made it to the brakes yet. Figured I don't need to worry about it stopping if it won't stay running!!
                    Engine is coming around really nicely, I had it all purring really well together today but I think I chased the carbs too far trying to get them perfect. I went the homemade vacuum gauge route so it's a bit tricky. Compression seemed good too, 2 topped out at 150, one at 140, and #2 is 130... Doubtful the gauge is accurate but given that it hadn't ran in 15 years or so I'd say good signs that nothing tragic is going on in there- thoughts?
                    It is nice to have a couple projects to work on though so when you get frustrated with one you still have something else to do. Just make sure you fight that urge to take it out on the road once you get the engine running right until you get the brakes taken care of!
                    Nathan
                    KD9ARL

                    μολὼν λαβέ

                    1978 XS1100E
                    K&N Filter
                    #45 pilot Jet, #137.5 Main Jet
                    OEM Exhaust
                    ATK Fork Brace
                    LED Dash lights
                    Ammeter, Oil Pressure, Oil Temp, and Volt Meters

                    Green Monster Coils
                    SS Brake Lines
                    Vision 550 Auto Tensioner

                    In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

                    Theodore Roosevelt

                    Comment


                    • #25
                      Originally posted by Zeston View Post
                      I got sidetracked playing around with syncing carbs and checking compression, so I haven't made it to the brakes yet. Figured I don't need to worry about it stopping if it won't stay running!!
                      Engine is coming around really nicely, I had it all purring really well together today but I think I chased the carbs too far trying to get them perfect. I went the homemade vacuum gauge route so it's a bit tricky. Compression seemed good too, 2 topped out at 150, one at 140, and #2 is 130... Doubtful the gauge is accurate but given that it hadn't ran in 15 years or so I'd say good signs that nothing tragic is going on in there- thoughts?
                      Those numbers look good to me. I'd say that #2 is probably the cylinder that had the open valve on while it was sitting all those years. Rust build up and those rings not yet perfect. Give it some time and let the oil do its thing and check them in a few weeks.
                      Also check the valve clearances, you may find that #2 may be just below spec.(in other words, the valves open and close sooner in the cycle thus it doesn't have enough time to build compression as high as it could.)
                      If you find that you need some specific sized shims, some dealers will swap out shims with your old ones. (I bought mine from a BWM place for $7 each)
                      I also have a few extras, as others here too may have, so ask here and maybe one of us might offer up a shim or 2.
                      Hi, my name is George & I'm a twisty addict!

                      80G (Green paint(PO idea))
                      The Green Monster
                      K&N A/F, TC's fuse block, '81 oil cooler, TC's homemade 4-2 w/Mac Mufflers, Raptor 660 ACCT
                      Got him in '04.
                      bald tire & borrowing parts

                      80SG (Black w/red emblems & calipers)
                      Scarlet
                      K&N A/F, TC's fuse block, WJ5, Shoei bags, Raptor 660 ACCT.
                      Got her in '11
                      Ready for the twisties!

                      81H (previously CPMaynard's)
                      Hugo
                      Full Venturer, Indigo Blue with B/W painted tank.
                      Cold weather ride

                      Comment


                      • #26
                        Valve shims- great thought! I think I will let it settle in for a couple weeks before getting into diagnosing valve issues. I know the cam chain has never been adjusted, so after playing with the carbs again tonight I'll maybe tackle that, seems easy enough to do, I'll just have to read through all the tech tips/forums to see if there's any hidden dangers!
                        1979 SF
                        Rehabilitating a Well Loved Classic

                        Comment


                        • #27
                          Sounds like my thread. Lmao! Just read through and was thinking that has he color tuned the carbs? I know for sticking valves put a little pub in the cylinders let them sit for a couple days.
                          79 SF

                          Wow, did I just give advice? should I be doing that?

                          1983 GL1100 bored to a 1300 sold
                          1976cb750 project gifted to brother
                          1979 xs1100s currently working on


                          Wanting to have that head turner that makes people shut up!

                          Comment


                          • #28
                            Hi Zeston,
                            I'm late to the fair on this one but can still add a little to the pot.
                            Spring loaded automatic centerpunch is the best for float pin removal.
                            (Don't grind the point flat, the little dent left in the pin will help center the punch next time)
                            Both Donebysunday and myself learned that trick years ago from Bill Denton on the XS650 list.
                            The best way for jet removal.
                            Use a drill press (unplug it!)
                            Grind up a long series screwdriver bit to be a perfect fit in the carb jet.
                            Chuck the screwdriver bit, put the carb body on the drill press platform,
                            bear down hard on the drill press feed handle to keep the screwdriver bit in the jet's screwdriver slot.
                            Back the chuck out by hand.
                            Works on most jets, even the really cratered ones.
                            Not losing those little parts.
                            Put the carbs inside a cafeteria tray to work on them. Flying parts will bounce off the tray edges rather than disappearing under a bench.
                            Last edited by fredintoon; 07-17-2013, 12:09 PM.
                            Fred Hill, S'toon
                            XS11SG with Spirit of America sidecar
                            "The Flying Pumpkin"

                            Comment


                            • #29
                              be careful with those pins. if you bend them let me know. I got some with my rebuild kit that I will send to you.
                              79 SF

                              Wow, did I just give advice? should I be doing that?

                              1983 GL1100 bored to a 1300 sold
                              1976cb750 project gifted to brother
                              1979 xs1100s currently working on


                              Wanting to have that head turner that makes people shut up!

                              Comment

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