Knock under load

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • sidecarKev
    XStremely XSive
    • Oct 2003
    • 219
    • Wisconsin

    #1

    Knock under load

    With my new floats my bike runs pretty good. I have noticed a knock in the engine when its under load. Especially when starting from a stop. I checked the valve clearances a couple months ago when I had the bike apart and made a few changes, should be still good. Fresh fluid changes. Could timing be slightly off? Its a pretty noticable knock.
    Kevin
    '79 XS1100 w/ Sidecar "SOLD"
    [URL=http://webpages.charter.net/kbhahn/sidecar1.html]My Webpage[/URL]
  • Geezer
    XS-XJ Guru
    • May 2003
    • 2985
    • Willamina, Oregon 97229

    #2
    Are you using premium fuel?

    Geezer
    Hi my name is Tony and I'm a bikeoholic.

    The old gray biker ain't what he used to be.

    Comment

    • sidecarKev
      XStremely XSive
      • Oct 2003
      • 219
      • Wisconsin

      #3
      No
      Kevin
      '79 XS1100 w/ Sidecar "SOLD"
      [URL=http://webpages.charter.net/kbhahn/sidecar1.html]My Webpage[/URL]

      Comment

      • TopCatGr58
        Administrator
        • Jul 2002
        • 12650
        • Portsmouth, Va.

        #4
        Hey there Kev,

        As Geezer suggested, you may need to up the grade of fuel you're using, especially since your bike is under a considerable heavier load than a NON-sidecar XS! Remember, the octanes of regular back in the late 70's and early 80's wasn't too far from our premium now, IIRC!? I use premium in mine, but I also have a big bore kit with higher comps!!

        Don't "Knock it" till you try it, PUN INTENDED!!!
        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

        • sidecarKev
          XStremely XSive
          • Oct 2003
          • 219
          • Wisconsin

          #5
          Is that really all it could be? Sounds almost to easy. Nothing can be that easy for me. More than likely it is a $0.69 crankshaft o-ring that requires a complete engine teardown.
          Kevin
          '79 XS1100 w/ Sidecar "SOLD"
          [URL=http://webpages.charter.net/kbhahn/sidecar1.html]My Webpage[/URL]

          Comment

          • uk1.1s
            XStremely XSive
            • Oct 2002
            • 365
            • Surrey UK

            #6
            Uh-oh

            Hate to admit it Kev.... but the only time my XS1100 engine 'knocked' it was the crank bearings (Big End).

            Was worse under load and sounded at first as though it was coming from the cams....

            Try putting a long screw driver tip against the engine cases in different places and put your ear up against the other (handle) end. Crude but effective way of tracing internal sounds to the right part of the engine... honest.

            Best of luck

            Graham
            XS1.1 sport - Sold June 2005 :-(
            Guzzi 850
            Z1000

            Comment

            • Geezer
              XS-XJ Guru
              • May 2003
              • 2985
              • Willamina, Oregon 97229

              #7
              Originally posted by sidecarKev
              No
              Try premium, you may be experiencing detonation.

              Geezer
              Hi my name is Tony and I'm a bikeoholic.

              The old gray biker ain't what he used to be.

              Comment

              • sidecarKev
                XStremely XSive
                • Oct 2003
                • 219
                • Wisconsin

                #8
                Well it turned out that cyl #3 wasn't pulling its weight. Pipe was colder than others. Took the carbs off AGAIN, reset the float heights, and did a general cleaning. Put it back on, (getting faster and faster every time) and it had power like I never had before. I set the floats a little lean and fixed a rich condition I had at low rpm's. It worked. Now I have no problem from a stop. I'm hoping this is the last time I need to have those carbs out for a while. I also filled up with 92 octane just for good measure.
                Kevin
                '79 XS1100 w/ Sidecar "SOLD"
                [URL=http://webpages.charter.net/kbhahn/sidecar1.html]My Webpage[/URL]

                Comment

                Working...