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Thread: Leak Down Test

  1. #1
    Matrix 200 suparoo's Avatar
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    Leak Down Test

    I want to do a leek down test on the Matrix. Is it ok to leave the carbs on a pressurise them as well ? How much pressure ? As you can see the MAG is lean and I want to check for leeks before more mucking with the jets, out to 150's on the mains and still not looking good.
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  2. #2
    Matrix 200 suparoo's Avatar
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    Once I've found out how to do the leak down test and "if" it turns out to be the seal behind the stator can it be changed in place or does the case have to be split ?.
    Is it common to have that seal leak? and wouldn't the stator housing be sealed anyway stopping the case sucking air. My plan is to make some blanks to fit on the carbs in place of the air filters rather than taking off the carbs. Is that ok or will it damage the carburetors by having them pressurised?

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    Hydrotoys's Avatar
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    Seal behind stator needs replacing. Cases...

    Pull carbs, so that you don't warp the fuel pumps

  4. #4
    Matrix 200 suparoo's Avatar
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    Is it an engine out job?

  5. #5
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    You will need to pull the engine,the cases will have to be split.Are you sure you don't have a carb restricted?

  6. #6
    Matrix 200 suparoo's Avatar
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    Just finished the leak down test held 6 psi for 15mins before I released the pressure. I pulled the side off the carb and checked the filter in there all looked good.
    Both the MAG and PTO carbs have pulse lines on them and they feed the centre carb with fuel so if it was lack of fuel wouldn't it also affect the centre carb? . What should I be looking for ? in the way of a restricted carb.
    Randy suggested going out to 155's on the back cylinders and 160 on the front, so looks like thats my next move.
    But if any ideas spring to mind on that pto carb I am still open to suggestions.

    Cheers
    John

  7. #7
    Hydrotoys's Avatar
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    John,
    I'm a little out of the game with the domestics, but EVERY dosmestic engine we ever had was a little lean and/or hot on the front cylinder. If it passed the leak down test (or the 2 beer test as I like to call it) then jet up the front cylinder and enjoy a long engine life. But that's just me.

    Maybe one more test... rotate the crank 90 deg and repeat the leak down test 3 more times. This should eliminate a dry seal and a wobbly crank.

  8. #8
    Matrix 200 suparoo's Avatar
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    Well I've drill out the jets to so big that the engine wouldn't go past 4450 rpm because it was so rich which was 170 mag and 165 pto, cnt. Then filled them and brought them back to 157 mag and 153 pto, cnt. and having troulbe some times going through the power band. Still lean.

    Have stripped the carbs and checked them out for fouling etc, all good. Pulled the fuel pickup from the tank and checked, all good.
    Im thinking I need to check fuel pressure ? How do you do that on the Klein tripples with pulse pumps ?

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