Engine Trouble Troubleshooting help needed after the first 30-40 minutes of riding a new ebay motor

Discussion in '2-Stroke Engines' started by dotcom, Jul 13, 2014.

  1. dotcom

    dotcom Member

    I just got my new motor working for the first time today that I bought from boygoesfast and I figured I would ride it for about a half hour to put some break in time on it and through the whole 30-40 minutes that I rode it, I made sure to take it easy but did accelerate just alittle to feel the thing out alittle. I had no problems that I could notice for the whole first 30-40 minutes except some extra vibration which I was going to take care of when I got back home and just as I was getting back home, I was going to pull in the driveway and said to the stop sign one last time and back and I proceeded to the stop sign and back for the last time and it died with a small POP! POP! at the end. It wasn't a hugh pop pop but it was some kind of a small pop pop which I thought I felt come from the carb like a tiny bit of gas pop popped with it. I gently tried to restart it a couple times after that and it acted like it wanted to start but would not.
    UPDATE: Here's a short video for a possible cause that I think caused it. In the video I am showing the carb needle which has me confused because with the normal carbs that ususally come with most kits, the needle is attached to the spring inside the carb and when you twist the throttle the needle moves up and down but mine is not attached to the spring and is not moving up and down. Im not sure if this is normal with my particular carb or not. This is why I ask. I spend $70 on the upgraded carb and they said its one of the best ones I can have with my kind of kit and they installed it for me so I did not notice if the needle is assembled like those of the cheap carbs . I have a feeling that is the issue so I ask. I think the grooves in the needle that keeps it attached to the spring somehow gave way and thats why the needle is not moving anymore when I twist the throttle. Can anyone confirm this or is this normal with some certian carbs? Also, after I got back home, I started to loosen the screws to maybe try and insert rubber to reduce some extra vibrations and maybe mount the engine another way onto the bike so that there isn't so much of a slant and thats when I removed the air filter and noticed the carb needle not moving.
    I also want to know if its good or bad to have such a big slant or if its better for it to be as straight as possible. I figure straight is better to regulate the gas flow better but again, this is why I ask. Im kinda new to these kits. Thanks
     
    Last edited by a moderator: Dec 15, 2015

  2. crassius

    crassius Well-Known Member

    take the top off the carb & remove the slide to see if the needle is still attached - needle is long & hard to see it move

    do not put rubber in the engine mounts - use a small piece of PVC pipe between rear mounting block and frame - be sure that the rear mounting studs are as close to perpendicular to the frame as possible since this mount takes all the force of the engine

    the lower the engine is mounted, the less vibration there is (on most frames) so you might have to lower the pedal side chain guard to sit as close as possible to its chain to get the engine low

    EDIT: oh yeah, those pops - check that your crank seals are still holding
     
  3. dotcom

    dotcom Member

    okay so the needle should absolutely be attached and move up and down?
     
  4. crassius

    crassius Well-Known Member

    yes

    EDIT: if it is loose, check all over & handle everything carefully 'cause there's a missing clip that you must find (or at least be sure has not fallen into the motor)
     
  5. desertsteve60

    desertsteve60 New Member

    NO, that is a Delorto clone and that is an emulsion tube, that is if that is the carb that you have. If you have the stock NT round slide carb the needle will move with slide.
     
  6. dotcom

    dotcom Member

    No? I have it opened up and there does not seem to be the clip anywhere and when I try to pull the needle out, I will not budge. I can get some pictures up in a sec
     
  7. crassius

    crassius Well-Known Member

    if it isn't a needle, it probably shouldn't move - if it is a needle, it must move & have a clip
     
  8. dotcom

    dotcom Member

    That silver odd shaped thing fell out when I turned it upside down and am not sure which way it was supposed to go. The carb does not say dellorto clone but it does have the name RUNTONG on it. Here are some pictures

    carb (1).jpg carb (2).jpg carb (3).jpg carb (4).jpg carb (5).jpg carb (6).jpg carb (7).jpg carb (8).jpg carb (9).jpg carb (10).jpg carb (11).jpg
     
  9. desertsteve60

    desertsteve60 New Member

    That is not a needle, it is a tube that is pressed into the carb. If you look closely you will see two small holes that allow fuel to come up from the float bowl for idle and low throttle. Do not try to pull it out!!
     
  10. dotcom

    dotcom Member

    lol I tried but I did not damage anything I assure you
     
  11. desertsteve60

    desertsteve60 New Member

    Although many people have had good luck with the "RT" carb I have not. If you have a stock NT carb put it on, if not buy one, they are like $10.00 on EBay and are IMHO much easier to work with and tune. And they have a needle and clip.
     
  12. dotcom

    dotcom Member

    it seems that needle thing is sitting almost flush down in there but I would think it should stick out just alittle for the round knob that gets turned to increase the idle higher or lower but when I turn the dial it does not touch the needle thing. Im wondering if thats normal. If I should explain further let me know. Otherwise im condunsed now
     
  13. dotcom

    dotcom Member

    I have had good luck with this "RT" carb for a good 4-5 months without any need to adjust but I thought it was a needle so is it or isn't it? Now I think its not so getting it back together is the only thing now but im having a hard time. The spring usually has plastic grooves where is usually sits and stays but the plastic on mine will no longer let it stay. Are there any videos for assembly of this "RT" carb?
     
  14. desertsteve60

    desertsteve60 New Member

    The idle adjust screw only touches the slide (that rectangular thing that slides up and down in the carb). It's not supposed to touch the tube (that needle thing)
     
  15. dotcom

    dotcom Member

    I finally got the carb back together again. whew! It took a few tries but I finally put the puzzle back together, lol. So it was not the needle issue afterall. I thought the clip in the needle came off and thats what caused the small pop pop sound because the needle was stuck jammed to the bottom or something. So something else has caused this. Now to figure out just what. I will check the crank seals but I doubt thats the problem because they are not even 1 hour old but I will check. Any other suggestions?

    Is it possible that the pop pop and stop could be caused by the fuel oil mixture? This is the first time this engine has ran and I am sure the there was only about 25:1 rather than the suggested 16:1 for the break in period but would this be possible to have caused the pop pop and stop? I got a new bottom end for another issue I was having and I already had a mixture of 25:1 in the tank.
     
    Last edited: Jul 13, 2014
  16. dotcom

    dotcom Member

    I changed the gas and tried to start it but it will not start. I pedalled it and tried a few times and it acts like it wants to start but doesn't.
     
  17. dotcom

    dotcom Member

    I just checked for spark and im not getting any!!!!!!!! Im hoping thats all it is but after check the wiring and the connectors, everything seems connected properly but still not getting spark. I checked the actual spark plug and thats not it either. Im thinking maybe its the CDI. I have 2 more and will check that next
     
  18. dotcom

    dotcom Member

    I've tested with two CDI's and 3 spark plugs but still no spark.
     
  19. crassius

    crassius Well-Known Member

    read on the board here about checking the mag coil with a multimeter
     
  20. dotcom

    dotcom Member

    luckly sooner than later I was bright enough to check for spark and narrowed it down to the coil. I changed it and the bike is running again. Always check for spark if its something you don't have a clue about!!! Any specific (or list of specific) possibilities it could have been that the coil went bad after less than an hour of use on it and the pop pop sound once the coil gave out?
     
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