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  1. #1
    PWCToday Guru E350's Avatar
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    Dial Gauge Recommendation for setting Ignition Timing?

    Merry Christmas guys and gals!

    Do any of you have a link or other recommendation for Dial Gauge for setting Ignition Timing with the spark plug hole adapters?
    Learning Slowly...

  2. #2
    PWCToday.com Is My Home Away From Home Myself's Avatar
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    Re: Dial Gauge Recommendation for setting Ignition Timing?

    What engine are you working on? The only adjustment is stator or possibly flywheel key.
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  3. #3
    PWCToday Guru E350's Avatar
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    Re: Dial Gauge Recommendation for setting Ignition Timing?

    Myself: Merry Christmas!

    '94 701cc Yamaha Superjet 62N engine. I have the replacement stator to install, but I need to make sure that it is correctly timed when I install it don't I?

    While I can see how a dial indicator can be used to find top dead center, I don't know how to achieve 15 degrees B(efore)TDC by using it.

    It expresses itself in terms of mm, not degrees.

    Additionally, I don't see how I can tell when the plug sparks if the flywheel is off.

    I know this can't be magic, but I am having trouble finding info on it and although my oem Yamaha Superjet Service Manual describes the Dial Indicator for engine tuning under the Special Tools section, nowhere does the manual say how to use the dial indicator or how to time the engine.

    If you have any good links for timing the Yamaha 94 701cc Superjet, will you please share them?

    (I am going to have to run to the Post Office to pick up one of my wife's Christmas presents before they close, so I will check back when I return.)
    Last edited by E350; 12-23-2017 at 07:13 PM.
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  4. #4
    PWCToday.com Is My Home Away From Home AC 46's Avatar
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    Re: Dial Gauge Recommendation for setting Ignition Timing?

    There is a mesurement in mm.mabey in the specs.
    R.I.P. Super Sic

  5. #5
    PWCToday.com Is My Home Away From Home Waxhead's Avatar
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    Re: Dial Gauge Recommendation for setting Ignition Timing?

    1.496 down the bore
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  6. #6
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    Re: Dial Gauge Recommendation for setting Ignition Timing?

    There is a mathematical relationship (formula) between the rotation of the crankshaft and the vertical travel distance of the piston. Each one degree of rotation translates to a sum quantity of millimeters to travel. The key measurements that you need to know is the rod length and the crankshaft web offset. From there you can figure out how many millimeters of piston travel corresponds to 15 degrees of advance before top dead center. The number is probably around 1.5 mm but you need that exact number to two decimal places and a dial gauge that's that accurate. As well, make sure the piston is as square as possible in the cylinder by rocking past that distance and bringing it back to that distance.
    Last edited by johnjetski; 12-23-2017 at 10:48 PM.
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  7. #7
    PWCToday Guru E350's Avatar
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    Re: Dial Gauge Recommendation for setting Ignition Timing?

    Waxhead and for others who may be interested, here is the link for the Yamaha Special Tool Dial Gauge (and extension recommended) by Yamaha in my oem Service Manual:

    https://www.yocracing.com/accessory_...product=709648

    yu-03097-b.jpg
    Last edited by E350; 12-23-2017 at 11:23 PM.
    Learning Slowly...

  8. #8
    PWCToday.com Is My Home Away From Home Waxhead's Avatar
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    Re: Dial Gauge Recommendation for setting Ignition Timing?

    Quote Originally Posted by johnjetski View Post
    There is a mathematical relationship (formula) between the rotation of the crankshaft and the vertical travel distance of the piston. Each one degree of rotation translates to a sum quantity of millimeters to travel. The key measurements that you need to know is the rod length and the crankshaft web offset. From there you can figure out how many millimeters of piston travel corresponds to 15 degrees of advance before top dead center. The number is probably around 1.5 mm but you need that exact number to two decimal places and a dial gauge that's that accurate. As well, make sure the piston is as square as possible in the cylinder by rocking past that distance and bringing it back to that distance.
    If only some one knew what that measurement was
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  9. #9
    PWCToday.com Is My Home Away From Home Waxhead's Avatar
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    Re: Dial Gauge Recommendation for setting Ignition Timing?

    Quote Originally Posted by E350 View Post
    Waxhead and for others who may be interested, here is the link for the Yamaha Special Tool Dial Gauge (and extension recommended) by Yamaha in my oem Service Manual:

    https://www.yocracing.com/accessory_...product=709648

    yu-03097-b.jpg
    sweet, a bit more than i wanted to pay but a cool unit
    Check out wax racing on facebook for all your billet ski parts your looking for

  10. #10
    PWCToday.com Is My Home Away From Home AC 46's Avatar
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    Re: Dial Gauge Recommendation for setting Ignition Timing?

    Quote Originally Posted by Waxhead View Post
    sweet, a bit more than i wanted to pay but a cool unit
    Yes how strange no spec.for static test.
    R.I.P. Super Sic

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