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  • no pressure...

    ok, so i got the starter to turn over today and there was air coming out of the mufflers. i finally got around to checking the pressure on each cylinder, and nothing. i assume i'm checking correctly (taking one plug out and then screwing in the gauge then turning the motor over) i thought of a couple things, then i decided to check my gasket kit to see what gaskets are left over. sure enough, the gasket that is for the camshaft/timing chain opening was never installed (i feel like an idiot ) so i thought about it some more, and wouldn't i still get some kind of pressure since the rest of the motor is covered up and the headers/mufflers are on? wouldn't the needle at least move some? so is the gauge broken or is the camshaft gasket what is causing the problem? i inspected the pistons and cylinders previously, and they were in great shape.
    1979 xs special, just finished the top end rebuild and then i still have lots of work.
    progress thus far...
    http://s1268.photobucket.com/albums/...t=IMAG0202.jpg

    "If it runs bad, it's usually the carbs. If the tires go flat, I suspect the carbs. If the wind blows the bike over, the carbs were probably to blame. If my wife yells at me about something, I tell her to talk to the carbs" -Incubus

  • #2
    The camshaft tunnel gasket is not used. Did you actually get one in a new gasket set?
    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


    • #3
      The head gasket not the valve cover is what seals the cylinders and yes you could have a guage with a problem. What you can do is put a finger or thumb in/over the sparkplug hole and see if there is enough pressure to push your finger loose. If you have small skinny fingers do not stick them half way in the hole the piston may hit it. If you have even weak preasure it should blow your finger loose. Check all cylinders and see what you have. If it blows your finger out and the guage does not register more than 60 PSI I bet its broke or the release is stuck.
      To fix the problem one should not make more assumptions than the minimum needed.

      Rodan
      https://www.youtube.com/watch?v=khm6...liHntN91DHjHiS
      1980 G Silverbird
      Original Yamaha Fairfing and Bags
      1198 Overbore kit
      Grizzly 660 ACCT
      Barnett Clutch Springs
      R1 Clutch Fiber Plates
      122.5 Main Jets
      ACCT Mod
      Mac 4-2 Flare Tips
      Antivibe Bar ends
      Rear trunk add-on
      http://s1184.photobucket.com/albums/z329/viperron1/

      Comment


      • #4
        ok, so i did the "finger check" (insert sophomoric joke about high school here) and there was suction and pressure out. i had the carbs fuel lines filters etc, i could tell the spark plugs were working, so why didn't it start? any ideas?
        1979 xs special, just finished the top end rebuild and then i still have lots of work.
        progress thus far...
        http://s1268.photobucket.com/albums/...t=IMAG0202.jpg

        "If it runs bad, it's usually the carbs. If the tires go flat, I suspect the carbs. If the wind blows the bike over, the carbs were probably to blame. If my wife yells at me about something, I tell her to talk to the carbs" -Incubus

        Comment


        • #5
          There are three things you need for an engine to run, fuel, compression, and ignition (spark). If it won't run your missing at least one.
          Greg

          Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid.”

          ― Albert Einstein

          80 SG Ol' Okie;79 engine & carbs w/pods, 45 pilots, 140 mains, Custom Mac 4 into 2 exhaust, ACCT,XS850 final drive,110/90/19 front tire,TKat fork brace, XS750 140 MPH speedometer, Vetter IV fairing, aftermarket hard bags and trunk, LG high back seat, XJ rear shocks.

          The list changes.

          Comment


          • #6
            As to the compression test , you should remove ALL of the spark plugs at the same time, so you don't have any compression to fight against in the other cylinders while you're testing the one. Throttle is to be wide open, or just not have carbs mounted, strong fresh battery. This should then get you some decent COLD readings, but it's suggested that it be done with a warmed up engine.

            As to not starting, as stated, fuel, air, compression, and spark. IF the battery is weak, especially after doing the compression testing, you may have been dropping below the 10.5 V threshold where the TCI would not work! Charge the battery, ensure the voltage is close to 12 volts while cranking. Did you clean out the starter jet in the float bowl during the carb cleaning? Do you have the Enrichener pulled out/on??

            T.C.
            T. C. Gresham
            81SH "Godzilla" . . .1179cc super-rat.
            79SF "The Teacher" . . .basket case!
            History shows again and again,
            How nature points out the folly of men!

            Comment


            • #7
              thanks guys. and i was using my car to jump the bike, so i'm assuming it had enough power. i'll tinker around a bit more and then try to start er up again.
              1979 xs special, just finished the top end rebuild and then i still have lots of work.
              progress thus far...
              http://s1268.photobucket.com/albums/...t=IMAG0202.jpg

              "If it runs bad, it's usually the carbs. If the tires go flat, I suspect the carbs. If the wind blows the bike over, the carbs were probably to blame. If my wife yells at me about something, I tell her to talk to the carbs" -Incubus

              Comment


              • #8
                I'm not familiar with your situation, but it's helpful to know if you ever had the engine running or if the PO did. If this is a brand new project for you, there are plenty of things to check. Are the plug wires good and in the correct cylinders, are the carbs tight/no vacuum leaks, are you getting an indication that fuel is entering the combustion chamber (wet plugs),have you checked for spark on any plugs? If you know fuel is getting to the combustion chamber and there is spark you are at least 50% there. You will also need to make sure your cams are in time and the valves are decent.
                Can't beat the smell of gas & oil

                Comment


                • #9
                  when i got it, the cylinder head was off, so i put it all back together. i set the timing correctly, and wire are correct. i'll pull the plugs and check for spark and see if they are wet. PO said the engine was running before the head was removed.
                  1979 xs special, just finished the top end rebuild and then i still have lots of work.
                  progress thus far...
                  http://s1268.photobucket.com/albums/...t=IMAG0202.jpg

                  "If it runs bad, it's usually the carbs. If the tires go flat, I suspect the carbs. If the wind blows the bike over, the carbs were probably to blame. If my wife yells at me about something, I tell her to talk to the carbs" -Incubus

                  Comment


                  • #10
                    Originally posted by Shockman54 View Post
                    when i got it, the cylinder head was off, so i put it all back together. i set the timing correctly, and wire are correct. i'll pull the plugs and check for spark and see if they are wet. PO said the engine was running before the head was removed.
                    Never trust a PO, always verify for yourself before believing. Unless you have some personal connection with the PO and then you can maybe put a slight bit of trust in that person.
                    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


                    • #11
                      Originally posted by Shockman54 View Post
                      ....PO said the engine was running before the head was removed.
                      If it was running, why did he pull the head?....
                      Fast, Cheap, Reliable... Pick any two

                      '78E original owner - resto project
                      '78E ???? owner - Modder project FJ forks, 4-piston calipers F/R, 160/80-16 rear tire
                      '82 XJ rebuild project
                      '80SG restified, red SOLD
                      '79F parts...
                      '81H more parts...

                      Other current bikes:
                      '93 XL1200 Anniversary Sportster 85RWHP
                      '86 XL883/1200 Chopper
                      '82 XL1000 w/1450cc Buell, Baker 6-speed, in-progress project
                      Cage: '13 Mustang GT/CS with a few 'custom' touches
                      Yep, can't leave nuthin' alone...

                      Comment


                      • #12
                        he gave me a story where the neighbor wanted to take it apart and clean everything. i looked at the cylinders and inspected everything and it all looked good.
                        i actually just got it started, but its running pretty rough. i am going to have to adjust the valves again (heard some clatter from the left side) and it wouldn't rev up at all, so some tuning is in order. i got it started by hooking the fuel lines up to the upper T fittings on the carbs. im not sure if they are the correct ones because gas came out of the lower Ts when I turned on the petcocks. because of that i didn't run the bike very long. didn;t want to blow the bike up
                        1979 xs special, just finished the top end rebuild and then i still have lots of work.
                        progress thus far...
                        http://s1268.photobucket.com/albums/...t=IMAG0202.jpg

                        "If it runs bad, it's usually the carbs. If the tires go flat, I suspect the carbs. If the wind blows the bike over, the carbs were probably to blame. If my wife yells at me about something, I tell her to talk to the carbs" -Incubus

                        Comment


                        • #13
                          Fuel lines

                          The fuel lines should be connected to the lower t's
                          mack
                          79 XS 1100 SF Special
                          HERMES
                          original owner
                          http://i946.photobucket.com/albums/a...ps6932d5df.jpg

                          81 XS 1100 LH MNS
                          SPICA
                          http://i946.photobucket.com/albums/ad305/mack-055/2.jpg

                          78 XS 11E
                          IOTA
                          https://youtu.be/wB5Jfbp6SUc
                          https://youtu.be/RaI3WYHSuWA



                          Have recovery trailer and shop if you breakdown in my area.
                          Frankford, Ont, Canada
                          613-398-6186

                          Comment


                          • #14
                            Hey Shock,

                            I didn't re-read this thread, so I can't recall what if anything you've done to the carbs. The upper T's are VENT tubes only, and need to be open for the floats to work properly, otherwise, the pressure can't stabilize and they will not seal, and you get fuel leaking out the intake inlet bell, as well as possibly forward into the cylinders, past any open valves, and down around the rings, below the rings and contaminating the oil, which can then cause bearing failure!

                            These engines ARE NOISY in the top end, so a little clatter isn't anything major to worry about, as long as you know you got the valve clearances within specs, concentrate on the carbs next. Also, check the pickup coil wires..see tech tips for how, and repair if needed. See the carbs 101 thread for how to clean them properly without breaking stuff inside!

                            T.C.
                            T. C. Gresham
                            81SH "Godzilla" . . .1179cc super-rat.
                            79SF "The Teacher" . . .basket case!
                            History shows again and again,
                            How nature points out the folly of men!

                            Comment


                            • #15
                              Your lower Tees will need to be fixed or replaced. You aren't going much further before you handle that.
                              Marty (in Mississippi)
                              XS1100SG
                              XS650SK
                              XS650SH
                              XS650G
                              XS6502F
                              XS650E

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