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which position is TDC position

in 912iS Technical Questions 10 years ago
Hi,
Do you know which position is rotax TDC position?Thanks

  • Re: which position is TDC position

    by » 10 years ago

    Top Dead Center? for #1 piston this is where you lock the crankshaft... is this what you want to know?

    Cranklockpin.jpg (You do not have access to download this file.)
      
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  • Re: which position is TDC position

    by » 10 years ago

    Thanks,I want to check the compression.
    Step Procedure
    1 Operate the engine until the temperatures have stabilized for a period of 5 min
    (engine oil temperature between 50 to 70 °C (122 - 160 °F).
    2 Starting with cylinder head 1 move piston to TDC position.
    3 Remove the upper spark plugs. Prevent dirt or other foreigner particles from
    penetrating the engine (A).
    4 Screw adaptor (1) into the spark plug thread and connect up the two pressure
    gauges (2) with the orifice jet (3) between them (B).
    5 Now put constant pressure, between 5.5-6 bar (550-600 kPa) on the line and
    take readings at pressure gauge (C).
    6 Repeat this proceeding at all 4 cylinder heads.
      
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  • Re: which position is TDC position

    by » 10 years ago

    Forget about the crank locking for this job.
    remove the top spark plugs, install the compression tester fitting in one spark plug hole, place your finger lightly over the fitting and move the prop in the direction of rotation. You will feel the air being pushed out, and then being sucked back in. half-way between that is TDC.
    see compression testing video:
    http://www.rotax-owner.com/en/videos-topmenu/elearning-videos/181-diff
      
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