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Help. Setting fuel level on my carb... Drain screw stuck

Discussion in 'XJ Technical Chat' started by Victor Hugo, Nov 3, 2020.

  1. Victor Hugo

    Victor Hugo New Member

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    Hi guys, I need some help with my maxim, I'm trying to adjust the fuel level in the mikuni bs33 carbs for the xj700x, but when I tried to open the drain screw it looks like it's stuck, I used wd40 but it doesn't seems to work, the carb was sitting for years, any ideas?

    If I can't get the drain screw open, I'm going to set the height float height as in the manual, 17,5mm +/-1mm, but I would like to check the fuel level.
     
  2. Huntchuks

    Huntchuks Well-Known Member

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    A wet set is needed, not a bench set. WD-40 is not a penetrating oil. Try Liquid Wrench or PB Blaster instead.
     
  3. Victor Hugo

    Victor Hugo New Member

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    I used this too, It is pentrating oil but it doesn't work
     

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  4. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Remove the float bowl. Dry it good. Use some heat on the float bowl (200ºF is plenty) and then a handheld impact driver on the screw.
     
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  5. StahlMaster

    StahlMaster Active Member

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    In the past I've heated the screw with a 100W soldering iron, then cool it quickly (pot of ice water) It helps break the bond.
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

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    soak it , soak it some more and keep doing that from inside and out side of the screw.
     
  7. Victor Hugo

    Victor Hugo New Member

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    sorry for my ignorance, how could I heat the bowl?


    do I soak it in carb cleaner?
     
  8. Jetfixer

    Jetfixer Well-Known Member

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  9. XJ550H

    XJ550H Well-Known Member Premium Member

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    soak with penatrating oil on the head of the drain screw and in the holes in bottom of bowl you could drop it into a jar of acetone and automatic transmission fluid 50/50 mix.
    tou want to heat the screw with a torch it will expand the screw .
     
  10. Toomanybikes

    Toomanybikes Well-Known Member

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    If all your efforts fail I do have a set of Mikuni carbs that are in parts.
     
  11. Victor Hugo

    Victor Hugo New Member

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    I soaked it, it's still soaking, in the night I'll try to open it, I hope it works. I used the same oil "aflojatodo" I have used before, if it didn't work I will use the mix of acetone and trasmision oil. So the heat is a bad idea?


    Do you ship to Mexico?
     
  12. XJ550H

    XJ550H Well-Known Member Premium Member

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    heat will work
     
  13. bensalf

    bensalf Well-Known Member

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    screw the float bowl down onto a piece of wood , put the wood in a vice to use the impact driver
     
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  14. Toomanybikes

    Toomanybikes Well-Known Member

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    FF04F637-0F6F-4129-B2BC-D2C3B55209B6.jpeg Don’t be afraid to pour the coal to it. A good quality screwdriver and applying torque to it and heat until she pops loose. Have only lost the battle once in the last 5 years
     
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  15. cgutz

    cgutz Well-Known Member

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    I replaced my bowl drain screws with hex screws from xj4ever. Haven't had a single regret or problem since.
     
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  16. joejr2

    joejr2 Active Member Premium Member

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    I had that happen a few times and what I did was to first soak the screw in penetrating oil,
    then heated it with a dry heat gun, lastly I froze it by squirting it with the propellant from
    A can of compressed computer blaster air turned upside down. After alternating hot and
    cold A few times,I was able to back it out with a cordless impact screw gun. I have used this
    on a lot of stuck bolts
     
  17. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Many methods. Most involve taking advantage of the different expansion rates of the different metals, and bit of carefully applied force.
    Worst case (and there is a worst case), you center punch the screw and slowly drill out the center with increasingly larger drills until you hit the minor diameter of the threads, and then use a dental pick to peel out the remainder. I haven't had to resort to that with a float bowl drain screw yet, but it's worth knowing about.
     
  18. Polock

    Polock Well-Known Member

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    take the bowl off and screw it to a piece of wood now it's solid and won't twist or move, now do all the other things suggested
     
  19. Victor Hugo

    Victor Hugo New Member

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    Thanks everyone, I was finally able to get the screw out.

    If someone has the same problem, what worked for me was to heat it up with a torch for two minutes, I did it as in Toomanybikes' image, after that it was like magic, the screw came out easily, the torch costs about $ 10 dollars.

    upload_2020-11-17_16-11-16.png

    I also found this video, it may help someone else with the same problem.

     
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