Help!! I don't know what to do!

Discussion in '2-Stroke Engines' started by JaredL, Oct 6, 2016.

  1. JaredL

    JaredL New Member

    Hi, I am a beginner to all of this kind of stuff, so excuse me if I have to describe what something is if I don't know the name.

    So I bought my bike off a guy who builds bikes for a living (he has done it for 8 years so he knows what he is doing). I texted him about this issue and he doesn't know what it directly is either.

    This is everything that I'm having issues with:

    The bike is a 80cc 2 stroke that runs on a 20:1 ratio (91 Fuel : 2 Stroke Engine Oil)

    It worked fine for the first few weeks. It has around 70-80 miles on it. In the past few days, I can ride it, but at any random time (never got it over 20 minutes) it will stutter when I hold the throttle, but when I hold the clutch, the engine goes for throttle. When I get it to stop, sometimes the rear tire will drag. Sometimes it wont, maybe a coincidence.

    The gas tube between the tank and the engine just started slightly leaking out the top.

    It takes about 200-500 feet to start, it always has.

    Again, I'm a beginner, so please describe the best you can. I just need help!

    Thank you,

  2. zippinaround

    zippinaround Active Member

    He's been building these for years and doesn't know they aren't 80 cc and can't diagnose something simple , I'd say he's a liar , anyway back to the problem when you initially start e engine it idles fine? Or does it rev up straight away? Tighten the clamp holding the carb on also check the tightness or all nuts and bolts .
  3. crassius

    crassius Well-Known Member

    seems that you should have him look at it - things get loose and out of adjustment when a bike is new - 20:1 is usually only for the first tank or two of fuel, with 32:1 used thereafter (91 octane usually isn't needed either)
  4. JaredL

    JaredL New Member

    Ya I think he was lying, some of the things didn't add up.

    Anyways, I'll try those recommendations for sure. I actually read similar problems and most said the spark plug or gasket could have something to do with it.

    Before this all happened, my gas cap flew off the tank and into the road. I retrieved it, but missing the gasket. Auto Parts didn't have the gasket we were looking for, but we bought a bigger one and crafted it.

    There are pictures of the new gasket and the choke attached to this comment

    Attached Files:

  5. crassius

    crassius Well-Known Member

    if that gasket is blocking vent hole in cap, you may need to drill another one
  6. zippinaround

    zippinaround Active Member

    Also straighten that carb
  7. JaredL

    JaredL New Member

    How do I straighten/tighten the carb, and what exactly is the carb?
  8. Frankenstein

    Frankenstein Well-Known Member

    Oh my.....

    The first and last picture is the carb. Also known as a carburetor, and also known as 80% of the engine problems you'll ever experience. Get used to looking at it a lot.

    To straighten you might have no option but to get an offset intake manifold. It would. Appear you have it at an angle because the top and cable are in the way of the bike frame. You can either cut a big section out of the frame which I don't recommend or get an offset manifold, which will put the carb off to the right and keep the cables out from touching the bike frame. It makes it easier to adjust the carb too since you don't have to dingle with it to get to the parts.

    Off sets are pretty cheap, like 7 bucks top, this just lets you have an even float and bowl on the carb, which if off centered can affect how much has you get or not get when using the motor. This can create plenty of stupid problems that seem like other problems and cause you to tune wrongly and eventually decide to kill people.

    Don't be a people killer and even out your carburetor.
  9. JaredL

    JaredL New Member

    So basically my issue is that the carb is touching wires it should be touching?
  10. jaguar

    jaguar Well-Known Member

  11. Frankenstein

    Frankenstein Well-Known Member

    Well it's possible it might be causing an air leak, 200 feet to start is pretty damn far. Even 100. I can start mine in 3 feet hell I can just lift my rear end up and lightly press the pedals down and it starts.

    It might not be the carb, it could be the jet (inside the carb) it could be a fouled spark plug, or a failing mag/cdi or a blocked exhaust port.

    Start from the bottom up, one thing at a time.
    Cozmik Mezzenger likes this.
  12. Frankenstein

    Frankenstein Well-Known Member

    And he probably has a 32 spaced intake, you can physically see the difference, his picture is pretty conclusive
  13. JaredL

    JaredL New Member

    This is the other side of the clutch

    Attached Files:

  14. JaredL

    JaredL New Member

    I can take pictures of the whole system if it will help
  15. Looks pretty tight. Your bike frame has to conform with certain dimensional perimeters.

    My own bike lacks the proper space for the engine I have chosen. I am keeping my eye out for a frame that gives my engine more space. Unless you can lower your engine, you will have to get an offset intake manifold so you can then rotate that carburetor counter clockwise until the throttle cable is at zero degrees, or straight up and down. That way the carburetor can process the fuel and air more efficiently. Then end result will be faster starts for one.

    Attached Files:

  16. Here is the link to the offset that you are looking for.

    Attached Files:

  17. JaredL

    JaredL New Member

    The bike ran fine for a couple weeks and this all randomly started happening, is it possible something is messed up, maybe from hitting a bump?

    When we checked the spark plug, it was black. We cleaned it then put it back in. Could this be an issue too?
  18. Frankenstein

    Frankenstein Well-Known Member

    Could be a few things, start from the end of the problem and work backwards.

    Recently my engine had the retaining pin for my top piston ring either fail or fall out, it didn't harm anything but instantly the power loss was felt as the ring no longer seated well and allowed for blow by.

    Could be his exhaust got blocked up, with carbon, could be his spark plug is getting weak (some stock plugs just fail without any reason) could be a loose wire in the ignition system. Could be a failing gasket. Could have a dead mouse in the crank case and the bones and fur are messing things up. Maybe his float bowl has crap in it and it's having a hard time starting (I changed carbs a while back and everything seemed fine but first few runs took a lot of effort to start and even then the first couple moments of running were rough. Checked the bowl and somehow got a bunch of sediment in it, after a quick clean it ran like it never had a problem in the first place.)

    Hey maybe his jet is loose in the carb and at times letting too much gas in or something, maybe his choke lever got loose and it's randomly choking or partially choking the motor.

    One one way to find a problem, and that's to find it.
    Cozmik Mezzenger likes this.
  19. JaredL

    JaredL New Member

  20. JaredL

    JaredL New Member

    I've also noticed that there was one day where all the issues I've been having set aside and it ran perfectly. It was a warm afternoon with low humidity. That was the only day in between its issues that it was running. It went for 25 minutes then I turned it off.