Weak accelleration and performance when in gear

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  • buickyouth
    XStremely XSive
    • Apr 2004
    • 202
    • Chicago, IL
    #1

    Weak accelleration and performance when in gear

    Recently, I replaced the spark plugs, fuel and vacuum lines, cleaned off the carbs, replaced the air filter and did an oil change with filter replacement.

    Starting the bike up is much faster and easier now. And it seems to be a lot smoother at idle and when revving a little in neutral. Still, once any gear is engaged, accelleration is really really slow to respond and stuttering.

    My first inclination is that it's a timing / carb sync issue. But I'm not sure.

    Thoughts on troubleshooting and direction is greatly appreciated.

    Thanks,
    Ian
    I am a rhinoceros and my skin is three feet thick.
    //////////////WARSENAULT/////////////
    Tags: None
    • 3Phase
      XS-XJ Super Guru
      • May 2008
      • 5529
      • Simi Valley, CA
      #2
      Ian, sounds like the engine isn't hitting on all four. These engines will start and run on three, even two cylinders with just a little vibration, but they'll be down on power. You can narrow the problem by checking to see which, if any, header pipes are running cold or cooler than the others.

      The headers get hot fast so be careful and don't burn your fingers! Just drip some water on the headers one at a time and if it sizzles, it's hot.
      -- Scott
      _____
      ♬
      2004 ST1300A: No name... yet
      1982 XJ1100J: "Baby" SS Brakes, '850 FD, ACCT
      1980 XS1100G: "Columbo" SS Brakes, '850 FD, ACCT
      1979 XS1100SF: "Bush" W.I.P.
      1979 XS1100F: parts
      2018 Heritage Softail Classic 117 FLHCS SE: "Nanuk" It's DEAD, it's not just resting. It is an EX cycle.
      ♬

        Comment

        • CaptonZap
          XS-XJ Guru
          • Jun 2010
          • 1748
          • Denver
          #3
          Uuh, Scott, I think he only has three to start with, since I think that is what an XS750 is.
          He might be better served on the triples board, <http://yamaha-triples.org/category-view.asp>,
          although the physics is the same for all of them, so the trouble shooting will be the same. CZ

            Comment

            • petejw
              XS-XJ Guru
              • May 2005
              • 2269
              • sydney australia
              #4
              hi ian,

              whats the history of the bike, did it have this
              problem prior to u doing the work,
              float levels can have a big affect on acceleration
              have u set them correctly?
              carb sync will always help as well,
              u havent got any brakes sticking?
              valve adj correct?
              just a cpl of things to think about.
              pete


              new owner of
              08 gen2 hayabusa


              former owner
              1981 xs1100 RH (aus) (5N5)
              zrx carbs
              18mm float height
              145 main jets
              38 pilots
              slide needle shimmed .5mm washer
              fitted with v/stax and uni pod filters

              [url]http://www.youtube.com/watch?v=3pA8dwxmAVA&feature=mfu_in_order&list=UL[/url]

                Comment

                • 3Phase
                  XS-XJ Super Guru
                  • May 2008
                  • 5529
                  • Simi Valley, CA
                  #5
                  Oops, I didn't see which forum this was in and there's no .sig info.

                  Still, troubleshooting is troubleshooting: Ian, check the exhaust headers to see if the engine is hitting on all three cylinders and if any of them are running cold then get rid of it and get an XS1100!
                  -- Scott
                  _____
                  ♬
                  2004 ST1300A: No name... yet
                  1982 XJ1100J: "Baby" SS Brakes, '850 FD, ACCT
                  1980 XS1100G: "Columbo" SS Brakes, '850 FD, ACCT
                  1979 XS1100SF: "Bush" W.I.P.
                  1979 XS1100F: parts
                  2018 Heritage Softail Classic 117 FLHCS SE: "Nanuk" It's DEAD, it's not just resting. It is an EX cycle.
                  ♬

                    Comment

                    • Shacknasty
                      XStremely XSive
                      • Feb 2011
                      • 379
                      • SFV-SoCal
                      #6
                      If you haven't done a synch, adjust idle A/F mix, and synch again, that is where I would start.

                      Nuthin' wrong with a 750 triple. I like most of the XS series!

                        Comment

                        • rpgoerlich
                          XSive Maximus
                          • Dec 2007
                          • 643
                          • Katy, Tx
                          #7
                          Might check/replace the plug wires and caps. If I remember correctly, the 78XS750 had an inline resistor in the plug wire.
                          Easily corrected with new wires, plug caps and resistor plugs.
                          Richard

                            Comment

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