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Thread: Kawasaki kxt250 tecate3 87 carb problems

  1. #1
    Join Date
    Jun 2022
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    Poland-kalisz
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    Kawasaki kxt250 tecate3 87 carb problems

    hello i have a problem with my tecate. the spark plug is flooded with fuel, the carburetor is factory-set (35 small jet 270 big jet needle 5 position) and the engine is still flooded. also the fuel backs up towards the filter and there is too much of it near the diaphragm.

    fuel tank (7.5 liters) runs out in about an hour
    and it smokes sharply

    what could be the cause of this? spark plug recommended for kxt (br8es)

    Mikuni Vm34ss carburettor

    too much fuel on the float may be the culprit?
    Attached Thumbnails Attached Thumbnails kawasaki .jpg  

  2. #2
    Join Date
    Apr 2011
    Location
    Mexico
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    9,003
    Did it run better in the past, or is this trike new to you?

    Fuel blowing back through the carburetor into the air filter can be caused by faulty reeds. Your fuel economy would be diminished as well. That’s where I’d look once you’re sure that your float full height is correctly set.

    You mention the fifth position on your needle. Given that most needles only have five positions, is it at the top of the needle, or at the bottom of the needle? Unless you are at an extreme altitude, neither the top or bottom position of the needle would make sense if it is the factory needle. You might want to try going back to the center setting to see if it makes a difference.

    You didn’t mention your air screw either. Make sure it’s not completely shut, start around one and 1/2 turns out from the gently closed position and adjust as needed.

    What diaphragm are you talking about? Not familiar with Tecates, but I don’t know where they would be a diaphragm on the engine. Got a photo?
    It sucks to get old

  3. #3
    Join Date
    May 2006
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    The Open Road
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    4,729
    Sounds like the fuel is running past the float needle because the float is set wrong or debris on the needle. Nothing coming out of the bowl overflow? Is the overflow vent plugged?

  4. #4
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    Jun 2022
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    Poland-kalisz
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    hello, the needle is in the 5th position from the top and the MIKUNI VM 34SS carburetor does not have an air adjustment screw

  5. #5
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    Quote Originally Posted by ironchop View Post
    Sounds like the fuel is running past the float needle because the float is set wrong or debris on the needle. Nothing coming out of the bowl overflow? Is the overflow vent plugged?

    quite a lot of this fuel comes out of the float chamber

  6. #6
    Join Date
    Oct 2003
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    Las Vegas, NV.
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    2,446
    I'm not familiar with that particular Mikuni carburetor either, but all carbs operate the same basic way. I'm in agreement with the prior assessments so far. I can only imagine your issue stemming from 2 possible problems:

    1. If your float level is set to high, it would be pissing fuel out onto the ground, via the overflow vent. Fix: Set float level to correct height.

    2. If your float valve (needle valve) seat isn't sealing correctly, it won't cut off the flow of fuel into the float bowl, and once again, it would be pissing fuel out onto the ground via the overflow vent. Fix: Determine why the seat isn't sealing correctly. Either a damaged seat, or debris preventing proper seal. If it is a damaged seat, then replace the seat. If it is debris, a simple inline fuel filter would cure the issue.

    In either case, the excess fuel should never be able to make it into the engine unless the overflow vent is plugged up. Fix: Ensure overflow vent is free & clear.

    According to this exploded view, your air adjustment screw is #29, and the needle valve is #34.

    https://www.jetsrus.com/carburetor/c...iew_parts.html
    Last edited by Red Rider; 06-20-2022 at 11:23 PM. Reason: Added more fuel to the fire.
    Red Rider's Sand Machine Updated 07/23/14

  7. #7
    Join Date
    Jun 2022
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    Poland-kalisz
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    18
    my carb https://goparts.eu/en/genuine-oem/ka...987/carburetor


    the carburetor you gave is very similar to the one mounted in the tecate, but it is not a mikuni VM34SS. I will check what you advised me

  8. #8
    Join Date
    Apr 2011
    Location
    Mexico
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    9,003
    Quote Originally Posted by Maciejtecate87r View Post
    my carb https://goparts.eu/en/genuine-oem/ka...987/carburetor


    the carburetor you gave is very similar to the one mounted in the tecate, but it is not a mikuni VM34SS. I will check what you advised me
    I’ve never seen a two-stroke carburetor without an air screw before. If you could post some pictures up it would be great. You might have to get up to 10 posts before you can do so, but just post some nonsense until you get to 10 and then start putting up photos.
    It sucks to get old

  9. #9
    Join Date
    Jul 2010
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    Arkansas
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    Quote Originally Posted by El Camexican View Post
    I’ve never seen a two-stroke carburetor without an air screw before.
    I thought air screws were the norm for early two-cycle carbs and fuel screws were the norm for four-cycle carbs. I know that's not true all the time or for this application, I'm just bored and chiming in. My two-cycle moped carb just has a fuel screw, but that's a mutt of a machine.
    The story of three wheels and a man...

  10. #10
    Join Date
    Jan 2018
    Location
    California
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    103
    Quote Originally Posted by Maciejtecate87r View Post
    ...the fuel backs up towards the filter and there is too much of it near the diaphragm.
    From barnett468

    "What do you mean by "there is too much of it near the diaphragm."?

    What "diaphragm" are you referring to?

    As others have mentioned, the "needle" (fuel shut off valve) in your carburetor may not be sealing completely. Unfortunately, there is no way to check the fuel level in this particular carb with a hose as shown below unless you modify your drain bolt, so there are a couple options to determine if the float level is too high and/or if the needle is leaking. Below are a few.

    Remove the slide from the carb.
    Remove the carb.
    Drain the fuel out of the carb via the large nut on the bottom or by turning it upside down.
    Place the carb on a box or something next to the bike and below the level of the fuel tank.
    Connect a fuel hose to the tank and carb.
    Hold the carb upright.
    Turn the fuel on.
    If gas starts leaking out either end of the carb within 2 minutes, the fuel level is too high for some reason.
    Regardless of the results of the above test, turn off gas at tank.
    Drain gas in carb.
    Remove the float bowl.
    Turn carburetor upside down.
    Turn gas on and look at needle. If gas gas leaks out, the needle/seat is bad or the 0 ring on the outside of the needle seat is leaking, and the needle/seat assembly should be replaced.
    If you do not see gas leaking, then most likely your float level is tool high. The part number is 16030-1020, however, it will be hard to find.
    If you do not see gas leaking, remove the needle then try pressing down lightly on the tiny metal pin on it. If this pin does not move, you need to free it up but it can be tricky to do. Do NOT grab this pin with pliers as it can damage it.

    This is a common needle and seat. The seat is the brass part. The needles often have a rubber tip instead of the steel one shown below.



    Last edited by rpeters; 06-22-2022 at 04:44 PM.

  11. #11
    Join Date
    Jan 2018
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    California
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    Quote Originally Posted by Maciejtecate87r View Post
    and it smokes sharply
    From barnett468.

    "What oil and what ratio are you using?

    It will smoke more if it is running extremely rich."
    .

  12. #12
    Join Date
    Jun 2022
    Location
    Poland-kalisz
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    [QUOTE=rpeters;1528656]From barnett468.

    "What oil and what ratio are you using?

    IPONE SAMOURAI 20/1 (prefered in manual)

  13. #13
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    Jun 2022
    Location
    Poland-kalisz
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    I changed the float setting slightly, which made the tecate drive better, I will try to change to the perfect color of the spark plug

  14. #14
    Join Date
    Jan 2018
    Location
    California
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    103
    [QUOTE=Maciejtecate87r;1528660]
    Quote Originally Posted by rpeters View Post
    From barnett468.

    "What oil and what ratio are you using?

    IPONE SAMOURAI 20/1 (prefered in manual)
    From Barnett468

    Ok, this is a modern oil (100% Ester), and most likely 20:1 is WAY to rich (too much oil). You can probably mix this oil at 50:1 or 60:1, but check with a few people in your country that are using it in their dirt bikes and see what ratio they are using.

    The problem is that the factory recommendation for that bike was made in 1986, and was for Kawasaki oil, which was not a "condensed" oil at that time. Most modern oils are made in such a way that less oil must be used than what most factories recommended back then.

    Can you get maxima K2 oil?

    You can safely run Maxima K2 at 40:1 in that bike. I guarantee it. I run K2 at 50:1 in my 1986 KX250, 1981 YZ450, 1980 YZ250, 1987 CR250R, and 1988 CR250R, and I race all these bikes, and it is sometimes over 90 degrees f outdoors when I race them.
    Last edited by rpeters; 06-23-2022 at 05:55 PM.

  15. #15
    Join Date
    Jan 2018
    Location
    California
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    Quote Originally Posted by Maciejtecate87r View Post
    I changed the float setting slightly, which made the tecate drive better, I will try to change to the perfect color of the spark plug
    From Barnett468

    The float should be set to the stock setting and so should the jets.

    You need to figure out your potential oil ratio problem before you change any jets.

    The oil ratio will affect the plug color. More oil = darker plug color and more smoke. Less oil = lighter plug color and less smoke.

    Where are you located?

    What elevation is it where you are located?

    Do you have the stock exhaust pipe?

    Do you have the stock silencer?
    .
    Last edited by rpeters; 06-23-2022 at 06:03 PM.

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