No spring back in throttle

Discussion in 'Motorized Bicycle General Discussion' started by salserod, Sep 19, 2009.

  1. salserod

    salserod New Member

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    Anyone there for some help?
     
  2. bandito

    bandito New Member

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    I havnt seen any other problems with the stock springs in any threads so Ill assume you have a problem in your twist/lever throttle being too tight, your cable having a too sharp a bend in it or some thing sticking in the carb/linkage. Make sure you lube every thing with wd40 and every thing is free to move to let the spring do its job.......make sure the cable housing ends arent crimped too tight to restrict the movement of the cable through them also. Could just be way out of adjustment too.
     
  3. salserod

    salserod New Member

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    Thanks for the reply. I did some more investigating and I believe the problem is in the carb. I am new to this so please excuse my ignorance. There are no and the cable is moving freely but when I turn the throttle it does not spring back to idle position. So I took off the carb to see what was going on. This is where I am lost. There is a spring inside a brass sleeve and the cable is inside the spring and it goes through the slot in the brass sleeve. There is a needle that goes into a hole. It seems as if the brass sleeve is too tight and does not move very easy. Should it be like this? Also, when it is at full throttle the pin should be out of the hole correct. I am not sure how that mechanism works. Thanks.
     
  4. GearNut

    GearNut Active Member

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    The carburetor slide should be ablt to slide up and down very easily. Check the slide hole on the carburetor to see if it is out of round.
    Some folks have needed to sand the slide a teeny bit smaller in diameter with fine sandpaper.
    Also overtightening the slide cap on the carburetor is a no no. It will distort the slide hole.
     
  5. azbill

    azbill Active Member

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    there is also a little guide 'pin' inside of the carb body. it lines up with the slot in the slide
     
  6. Sydneysider

    Sydneysider New Member

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    Most of the time I found they dont always go back to close throttle position but once the engine is started, the vibration fixes that, the twist throttle wears in and springs back normally after a few runs..
     
  7. RadicalxEdward

    RadicalxEdward New Member

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    I have this problem too. If I take the carb apart so I can see the spring/slide/pin/etc and twist the throttle, it pulls the assembly up as it should, and if I twist the throttle back to it's normal position, the spring pushes the assembly back down, but it doesn't move without me manually moving the throttle. Is there supposed to be another spring in the throttle or something to help it spring back to it's starting position?
     
  8. crassius

    crassius Well-Known Member

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    sounds like your twist grip is rubbing on the handlebars or your cable is binding due to a sharp bend somewhere along its length
     
  9. RadicalxEdward

    RadicalxEdward New Member

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    Definitely no binds. I've lubed it twice with different lubes. I've got some lithium grease I'm going to try next. I've used wd-40 and a dry spray silicon lube
     
  10. 2door

    2door Moderator
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    WD-40 is not a lubricant. Don't use it on your cables. Either a light oil or remove the cable from the housing and apply grease. I prefer the oil.

    You need to locate the source of the bind. Take the cable end out of the twist grip and pull it with your fingers. Watch the carburetor throttle slide (barrel) as you pull. Does it move up and down smoothly? If not check the slide's fit in the carb body. If it pulls easily with the slide moving through the full travel then the problem is in the twist grip.

    Some of the thimbles, the part the cable wraps around in the grip, need to be trimmed slightly to allow them to rotate smoothly. Look at it closely and you might see mold flash that is binding the thimble. Also check that the twist grip moves effortlessly on the handlebar. Is there any bind there?

    Let us know what you find.

    Tom
     
  11. crassius

    crassius Well-Known Member

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    maybe something fell into the metal elbow at the throttle end?

    with both ends unhooked the inner should just about fall thru the outer
     
  12. RadicalxEdward

    RadicalxEdward New Member

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    Thanks. I'm pretty positive it's the grip. I used the wd40 on the metal of the handle bar. Not the cable just to be clear. I think you're right about the plastic where the cable attaches to the handle. It's a tight fit there. Ill try to clean it up with an xacto knife. Luckily this is one of my least severe problems. One of my engine covers blew off on a test run today. One of the few things I hadn't smothered in loctite. Not to mention if I don't keep it at 3/4-wot it stalls. Sometimes stalling no matter what. This project has been such a headache but I have to finish it so I have no choice. I'm lucky people like you guys have been helping me. But it's still hard describing things properly enough to diagnose problems over the Internet.
     
  13. CTripps

    CTripps Active Member

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    Sounds like it's time to make an adjustment to your carb, you must be running too lean.. Most likely the needle is dropping too far down into the fuel bowl, lower the clip on the needle a notch or two if you can.
     
  14. dumpstercrusher

    dumpstercrusher New Member

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    Did u fix ur throttle problem? i had the same problem where after everything was screwed back into the carb i woukd twist the throttle and it would not go back to normal. Soo what i did was open the throttle cable where it connects to the carb n took out the barrel and did the same thing, twist the throttle to see how it would act. that part was fine so it had to be the hole it was sitting in that i didnt mount it propperly. so i looked at the small barrel for the throttle where the pin n spring is at n on the side of the barrel there is a notch for where the idling screw would be touching. i just lined that up, rescrewed on the cap and that fixed my problem wit the throttle going back to place.
     
  15. Desert Rat

    Desert Rat New Member

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    I've seen that problem and a lot of times it can be traced to, to tight of a turn
    in the cable or if it's zip tied that may be to tight!
     
  16. dag_29307

    dag_29307 New Member

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    Can you post pics of your bike? Pics can describe a lot.
     

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