Throttle Issues

Discussion in '2-Stroke Engines' started by AndrewM, Apr 17, 2008.

  1. AndrewM

    AndrewM New Member

    Nice forum you guys got going here... I just bought a 2 cruiser bike with a 2 stroke engine. The previous owner told me it needed a new throttle cable, but I figured I might give it a shot at fixing it. I know very little about combustion engines, but what the heck, I'll give it a shot.

    So I took the throttle to carb connection off to make sure it was in decent condition
    All looked okay to me, when I use the handle throttle (twist kind) the spring condenses. I reattached the connection to the carb, bike will fire up but no revving or any action. I then took the air filter off and looked through while twisting the throttle to see if the pin moved at all, nothing. I guess this is the carb slide...

    Here's the question, do I need to order a new throttle kit, it looks like it is set up right, but when connected I don't have it tightened all the to the carb, it tight but I can still see several rows of grooves. Do I need to tighten with a wrench? The pin doesn't move at all, but like I said when I have it removed the spring is condensing...

    Help me out here folks, I appreciate it.
    Last edited: Apr 17, 2008

  2. Abeagle

    Abeagle Guest

    Andrew you will get more responses if you introduce yourself first in the "Introduce Yourself" forum. It is a courtesy and a rule here.
    And by the way Welcome to MBc.
  3. Ghost0

    Ghost0 Guest

    My first thought would be that the slide is getting caught on the guide pin. If you look down the opening the slide goes in, there is a little pin. There is a corresponding groove in the slide. Make sure these line up.
  4. AndrewM

    AndrewM New Member

    Not sure.....

    This is where I would look right? I don't see any groves.
    throttle-trouble.jpeg .

    There appears to be a small bump on the right side, no bigger than a 2 pin heads, should I look for the grove on the sides or on the bottom?
    Last edited: Apr 17, 2008
  5. Abeagle

    Abeagle Guest

  6. graucho

    graucho Active Member

    He's talking about the copper barrel needs to line up with that small nub inside of your photos carb body. Dude, you need to tip your bike on its side and spray it out with some carb cleaner Or take it off and give it a cleanin. Looks like a lot of junk in there.:smile: OOps Abeagle just said that a minute before me.
    Last edited: Apr 17, 2008
  7. AndrewM

    AndrewM New Member

    Yeah, it totally needs to get a thorough cleaning. I just wanted to ride around on it:grin: I'll give it a good carb cleaning tomorrow and line up the nubs. I want to right now but it's late and dark. I'll give an update tomorrow.

    Thanks much for all the advise this far...
  8. Andrew seeing that's it's a used purchase things may have gotten abused in your carb. For example someone may have gotten too overly excited on the throttle and thought the more force on that throttle the faster it will go &^%$#*(&...*&^%$#*@.
    25 bucks will get you a brand new carb at the DAX site. You may get by with the throttle cable. From the pic it doesn't look damaged.
    Try the carb cleaning first. I know 25 bucks is a lot of money for some of us. It definitely is for me.
  9. stude13

    stude13 Active Member

    hi; these little carbs are delicate, for sure you must tighten screws and bolts but be easy or you can warp the carb body. you might find that a thumb throttle works fine one thing is you cant put as much torque on the cable like you can with a twister. what kind of engine and carb, and bike kit? gas it stude13
  10. AndrewM

    AndrewM New Member

    Hey guys, here's an update... I fixed the throttle cable issue, aligned it up perfectly and can see the carb slide pin move up and down, like it should. I also cleaned with carb cleaner with the air filter removed.

    The bike starts off of pedal power and when i twist the throttle I can hear the engine try to rev, but that's it. I don't hear a 'put-put' or smell exhaust. Short of taking off the entire carb and cleaning, what might be the problem? The magneto seems to connected fine, as are the wires going to the little kill switch(?) box.

    I've tried operating in the on and off and half way possition (carb) and no change.

    The sparkplug looks clean and has a good connection..

    The bike itself is a 2-stroke 49cc engine. Not sure about any other specs, sorry.

    Thanks guys!
  11. Throw away that kill switch and cap off the white wire. Blue to blue,black to black.
    Down the road,check this out:

    But I'm still thinking that carb jet where the needle goes in is $%#^&%$#.

    At least 25 bucks isn't 150 bucks like in other engines.

    For now take that carb apart. It's really not difficult. In fact,this is the simplest carb I have ever seen in my 41 years of life.
    Really spray down your jet (the copper) maybe see if you can unscrew that and just clean clean clean. If it's really worn down it could affect how the needle seats in there.
    Last edited by a moderator: Apr 18, 2008
  12. I would check the clutch cable and make sure it isnt adjusted too tight....
  13. AndrewM

    AndrewM New Member


    So I took the carb apart and gave it a complete cleaning, reattached. Now it actually revs like a motor should, but she's developed another issue, gas overflow. It seems whenever I have the gas in the on position it starts to flow out of the airfilter space, and possibly out the small hole on the bottom of the carb. I looked at the floater and am pretty sure it's in there correctly.

    What could be causing this? I noticed that the gaskets that separate the bottom (with floater) to the top of the carb are pretty much non-existent, did they even exist in the first place? Can I simply JB weld where they connect to prevent spillage? I'm not even sure the gaskets are the issue since gas seems to be flowing out of the carb where the air filter connection attaches....

    So close yet it seems so far away from having a fully functional bike... Thanks again for all your help folks!


    I've looked at the thread with pictures of the carb completely disasembled and have come to the conclusion that my float isn't working how it should... Any ways to correct this? If the float's not working, gas will overflow, much like I'm witnessing, right? Am I even close to being on the right track?
    Last edited: Apr 18, 2008
  14. When you took the float lever off did you put that little pin back in the copper fuel intake line? Like a toilet bowl,that's the valve that stops fuel flow when the float bowl is filled enough.
    Look around your work area for it. It's tiny. It could have slipped out when you were disassembling without your knowledge.
    Last edited by a moderator: Apr 18, 2008
  15. AndrewM

    AndrewM New Member

    ****. I just transported the bike from my lady's house to mine after working on it, so if I'm missing a pieces I'm SOL. Does that piece go into the bottom part of the carb or the top? There's a metal piece that fits in a hole on the top and attaches to a 'U' shaped toilet-seat looking metal piece that would be pressed by the float.... I have that piece, but no small little pin......
  16. graucho

    graucho Active Member

    Photo of the float needle and pin. Do you have these?

    Attached Files:

    Last edited: Apr 18, 2008
  17. AndrewM

    AndrewM New Member

    I have the float needle, but I'd have to check on that pin. I don't think so, because I remember re-assembling the carb and the float needle and it's metal attachment seemed somewhat loose. I'll take a look tomorrow when it's light out. Thanks for the detailed pictures! I appreciate it.
  18. AndrewM

    AndrewM New Member

    Alright folks, sorry for the lag in an update, I took the carb apart again and lo-an-behold, the pin was missing. After a trip to Ace Hardware and the purchase or two completely useless parts, I ghetto rigged a paperclip to act as the pin, tightened and reattached the carb and PRESTO! Everything works now as it should. I need to get a new throttle cable eventually but for right now I'm having a blast riding my newly-functional bike.

    Lots of thanks to all you folks for helping me with my bike-issues. I think this bike will be the first of many motorized bicycles for me in the future. Thanks again, all, and happy trails!:grin:

  19. Scottm

    Scottm Guest

    Great team work guys! This is just your bike's way of getting aquainted with you and vice versa. Now when someone asks a carb question, you can refer them to this thread and look smart too.
    Once again I'm proud to be apart of MBc.