idle screw question

Discussion in 'General Questions' started by dotcom, Aug 6, 2014.

  1. dotcom

    dotcom Member

    I have an RT carb on my bike which has been great on my previous build but with this new build my idle screw is screwed all the way in and im still at a too low idle when stopped or when I pull the clutch in. I feel that If I could screw that idle screw in more, I feel could prevent this. Otherwise the bike is running fairly smooth. So what is the cure?
     

  2. crassius

    crassius Well-Known Member

    lean it out a bit more
     
    dotcom likes this.
  3. dotcom

    dotcom Member

    oil? its a brand new bottom end, hardly even broken in yet with just 5-6 total rides so far and im only on the second tank. Are you saying there is too much oil because the idle screw is screwed all the way in and im still at a too low idle when stopped with no room on the screw the increase the low idle. Something cannot be right. not sure though.
     
    Last edited: Aug 6, 2014
  4. butre

    butre Well-Known Member

    lean as in fuel/air mix. lower the needle
     
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  5. dotcom

    dotcom Member

    on my last journey of diagnosing a problem with the bike, I took apart this RT carb and first thought the needle should be moving up and down like a stock chineese carb and then finally someone that knew the RT carb said the needle doesn't move up and down like a stock chineese carb so I was trying to force mine out before i found this out and thats probably what is happening. I didn't force it out but might have just alittle
     
  6. crassius

    crassius Well-Known Member

    I see that the RT comes with an assortment of jet sizes - that might be the only way to adjust richness of mixture - somewhat like the CNS carbs that are a PIA to tune, I'd dump an RT for an easy to work with NT.
     
  7. dotcom

    dotcom Member

    I tried moving the needle again but it just does not seem to budge and no matter what I tried I am still having the same problem. I can't seem to move the needle no matter what I do. I tried with force to move it up or down. The only thing that did increase the idle was to unscrew the clutch cable a couple turns near the carb but that tightened the pedalling from being as freely as before. Now I wonder what will happen if I loosen the flower nut so it pedals more freely but I though it will pnly undo what I just did. After all though, I think the needle still needs to be forced one way or the other to get it right because the idle screw should be able to not have to be tightened all the way and still have a low idle.
     
  8. Fabian

    Fabian Well-Known Member

    :iagree:
     
  9. dotcom

    dotcom Member

  10. crassius

    crassius Well-Known Member

    standard carb for most kits
     
  11. dotcom

    dotcom Member

    I knew RT carb stood for runtong but not NT
     
  12. crassius

    crassius Well-Known Member

    not sure what the NT stands for, but there are many clones like the NTTC, the WH, and one that has just Chinese chars on it - they are cheap & easy to work with
     
  13. dotcom

    dotcom Member

    how is the needle lowered on a standard NT carb?
     
  14. Fabian

    Fabian Well-Known Member

    Unscrew the throttle cable housing from the Carburettor.
    The throttle slide (containing the needle) and the return spring can then be removed in one assembly.

    Pull the spring towards to top of the throttle cable adjuster. This will allow you to remove the throttle cable from the throttle slide.

    With throttle cable removed from the slide, the spring can then be removed from the slide.

    This will leave you with just the throttle slide and the needle sitting in the upper portion of the device.

    Now you can remove the washer and the needle, with it's attached "E" clip.

    Removing the "E" clip can be tricky, but once it's removed, place the "E" clip on the very top notch of the needle, which will (when reassembled) allow the needle to be in the lowest possible position.


    Reassembly is the reverse of the process described above.
     
    Last edited: Sep 11, 2014
  15. dotcom

    dotcom Member

    done, thx!
     
  16. Fabian

    Fabian Well-Known Member

    Always here to help, in any way i can.
     
  17. dotcom

    dotcom Member

    That definetely did the trick! Thanks again!
     
    Last edited: Sep 19, 2014
  18. dotcom

    dotcom Member

    if the RT carb has poor low end torque and the idle screw is screwed all the way in to stay at a fair idle, which jet should be put in between 60,65,70,75,80
    ?
     
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