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Valve adjustment problem.

Discussion in 'The Garage' started by Trimjohan, Apr 29, 2023.

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  1. Apr 29, 2023 #1
    Trimjohan

    Trimjohan XS400 Member

    10
    5
    3
    Sweden
    Hi!

    I’m adjusting valves on a xs400se
    I’m using the valve adjusting manual we have here. But something seems wrong when I try to.

    When I set it on ”LT” (compression stroke, not exhaust stroke) and check with the feeler gauge at the exhaust valve. The play is more than 0.6mm so it is way off.
    when I’m eye-balling the play on the intake/exhaust rocker arms it seems to be moving around 1.5mm

    The thing is, the adjustment screw/tappet is in the bottom, so no further adjustment is possible. Have I missed something? What’s wrong?

    Any help would be highly appreciated.
     
    Last edited: Apr 29, 2023
    Trimjohan, Apr 29, 2023
    Trimjohan, Apr 29, 2023
    #1
  2. Apr 29, 2023 #2
    CaptChrome

    CaptChrome XS400 Addict Top Contributor

    409
    148
    43
    Southern NJ
    Do you know anything about the history of the motor, like has it been rebuilt before you got it?

    Off of the top of my head, if head work was ever done, the valves used could be incorrect, the valve seats not installed properly or someone put different valve adjuster screws into the rocker arms. That or you have really bad cam wear.
     
    CaptChrome, Apr 29, 2023
    CaptChrome, Apr 29, 2023
    #2
  3. Apr 30, 2023 #3
    Trimjohan

    Trimjohan XS400 Member

    10
    5
    3
    Sweden
    Thank you.
    I would not be surprised if that’s the case.

    Previous owner claims he did not open the engine, but the owner before him might have.
    The adjustment screw heads looks like someone has messed around quite a bit before. He is an aquaintance, fortunately.
    I will check with him and see what he says.
     
    Trimjohan, Apr 30, 2023
    Trimjohan, Apr 30, 2023
    #3
  4. Apr 30, 2023 #4
    tstidham

    tstidham XS400 Addict

    224
    92
    28
    Philadelphia, PA
    Since you are adjusting the lash anyway, loosen and remove the lash adjuster screws and make sure they are the same length between intake and exhaust. Maybe someone lost the intake ones and just used what they had on hand and they were too short. You might want to remove the rocker cover to inspect the rockers for wear and the camshaft, though usually the lobe wears down, not the base circle.
     
    tstidham, Apr 30, 2023
    tstidham, Apr 30, 2023
    #4
  5. Apr 30, 2023 #5
    Trimjohan

    Trimjohan XS400 Member

    10
    5
    3
    Sweden
    That’s a good idea. Sounds logical. I will check the screws and otherwise take a look under the cover to see whats going on. Will be interesting to see. Hopefully nothing major.

    Thank you!
     
    Trimjohan, Apr 30, 2023
    Trimjohan, Apr 30, 2023
    #5
  6. Apr 30, 2023 #6
    Trimjohan

    Trimjohan XS400 Member

    10
    5
    3
    Sweden
    Just got some motor history from the previous owner…Yep, apparently nothing has been done except oil change and sparkplugs…since the ninties. Sounds in line with the tappet clearance.
     
    Trimjohan, Apr 30, 2023
    Trimjohan, Apr 30, 2023
    #6
  7. May 2, 2023 #7
    CaptChrome

    CaptChrome XS400 Addict Top Contributor

    409
    148
    43
    Southern NJ
    I am sorry to hear that. But normally over that time the valve clearance would get tighter, not looser as the kilometers piled on. I would definitely want to have a look under the valve train cover to really get a view of the cam lobes, the rocker arm wear points, etc.
     
    CaptChrome, May 2, 2023
    CaptChrome, May 2, 2023
    #7

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