Idle Mixture Screw?

Discussion in 'Engine, Fuel and Exhaust' started by Bodeen, Apr 16, 2014.

  1. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

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    So I went and finally threw the upgraded cam plate, oil pump, and cams in the old RK. Went to adjust my idle mixture a bit and of all things the screw is stuck! Yep, thats right the screw is stuck in one position. Cant loosen or tighten it. Of course I haven't had the carb out yet. Anyone got any ideas that may help un-stick it?
     
  2. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    The mixture screw does suffer a wee bit from corrosion of the white type so carb off and on the bench and give it some penetrating fluid and then use a hand impact driver with some light taps with a soft mallet and hopefully it wil shock the corrosion and start to move it may also be a good time to replace the o ring and spring and perhaps some copper grease to prevent it happening again
    If it is a stock cv it might be a good time to find a bucket for it and fit a mukni :D

    Brian
     
  3. Dr. Dolittle

    Dr. Dolittle Experienced Member Staff Member Moderator Contributor

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    A liberal application of PB Blaster left to soak in overnight has gotten some pretty stubborn nuts and screws to behave themselves for me.
     
  4. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

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    Thanks gents! I did try some PB Blaster but not being properly positioned, it really didnt do any good. I was hoping to not have to take it off but I guess I'll have to. Thank you Brian for trying to pry my wallet open!
     
  5. STEVE07

    STEVE07 Well-Known Member Staff Member Super Moderators

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    A blast with an electric heat gun will work. They are two different alloys that heat to different temps. The carb will heat faster and break the corrosion, increasing the thread size momentarily and that will allow you to remove the adjusting screw take it out and clean it. I have done this many times and never hurt a carb
     
  6. ciscokid

    ciscokid Member

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    ya the heat gun is a good idea . dont get dripping fuel or vapors in that heat gun .
     
  7. Jack Klarich

    Jack Klarich Expert Member

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    Turn the carb upside down, fill the screw with PB blaster, tap outside housing lightly, apply heat from heat gun or blow dryer, once you get screw out dont lose the spring add a dab of anti sieze to the threads
     
  8. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

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    Ok, while adjusting my push rods, I took the carb off and set it on the bench filled the hole with PB Blaster and let it set. Tried loosening, nothing. Tapped the screwdriver with a screwdriver, nothing. Broke out the Surefire torch and heated the around the screw to the point of worrying about to much heat, nothing. Now the screw is getting really chewed up and think maybe having to drill it out and replacing with the knob type. :bigsmiley21:
     
  9. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    That does not sound like a good position to be in as drilling out that one will not be easy without causing damage to the carb I still think a hand impact driver may help just ensure the screwdriver head is the same width as the screw head to help prevent the head slipping and causing further damage
    Take care or it may be the end of the carb

    Brian

    P.S. mikuni makes a good replacement carb should you need one :(
     
  10. motor

    motor Active Member

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    Not trying to be a smart .... .but the screw shouldn't be getting messed up no matter how tight .If the driver doesn't fit properly. don't use it. Slipping the screw driver in the head of the screw ,is on you. Much as it isn't want you want to hear ...Try some patience .Turn over and soak .Or pull everything out of carb and soak the whole thing. Taping ,soaking ,heating...eventually it will come out ...If not ...new carb..
    BTW why do you have to change setting with what you said you did