Carby Bike appears to constantly flood.

Discussion in '2-Stroke Engines' started by Motorized, Feb 22, 2012.

  1. Motorized

    Motorized New Member

    Hi guys,

    I have a RAW "80cc" 2 stroke engine on a beach cruiser that I bought used from somebody about two months ago. This was the first time that I ever rode anything like this, and I'm having a problem with what I presume is flooding.

    Letting gas through is just by means of a lever, so I never know if I'm letting too much gas out or not enough. If you open the lever all the way, the bike will continually flood. If you don't, it may go a while but then you feel it lose power (essentially runs out of gas). I don't get how you're supposed to know how far to open the lever.. and what if you go fast for a long stretch, do you need to adjust the lever while you're driving?

    Currently my bike doesn't work at all, leading me to my next question. Somebody who brought the bike to me left the lever open all the way, causing it to flood badly. I tried for 40 minutes pedaling around like a mad-man, and it just wouldn't start. As of right now, I have no idea what to do..

    In terms of this bike's ability to run, I did get it to run a few times (much more when I first got it). It would run 15-20 minutes in a best case scenario (hardly ever happened), but would usually run at least five minutes before stalling (presumably from flooding or not getting enough gas).

    Ultimately I would need this bike to commute to school. I'm a graduate student so coming late is not an option (they would decapitate you). Are these thing (motorized bikes) ever REALLY dependable? I mean this one has been a nightmare, but in general - are they dependable? Because if it's normal that they don't start every other (or even one out of ten) time(s) then it's just not dependable enough for me.

    So my questions are:

    -How do you know how far to open the gas lever/do you ever need to adjust it?

    -How do you know for sure that a bike is even flooded in the first place and what's the best way to un-flood it after you've force-pedaled it 40 minutes with zero success?

    -Is there any way to tell whether a bike is flooded or isn't getting enough gas when it doesn't work that doesn't involve taking apart the engine?



  2. David Lindsley

    David Lindsley New Member

    well i am new at this put win i am ride mine if i am at fill throtle for a while it runs out of gas and it seems like it is flooding.but if i open my gas cap it runs again. so it is a vacum ish you. like on a dirt bike has a vent on the tank. but if is flooding then it is something in carb the flote your the main jet fell out. it easy to fix. go to you tube and look it up step bye step how to fix flooded engine. good luck i gess you could shat the gass off pull the plug but get the dirt way form the plug and ride it bown the block with on plug it might clear it out put tap over spark plug boot so it does not ground. have fun.
  3. Big Red

    Big Red Active Member


    Yer not really Motorized yet, are ya? Bad news bro, If yer not ready or willing to work on an engine then your in the wrong hobby. The first thing you need to do is check that the float it set and working properly. This will involve turning screws and taking the bowl off the carb.
    If you're not willing to start taking things apart and learning about bicycle engines then I am wasting my time. I've only been doing this for about seven years. Some on this site have been building motorized bikes for MUCH longer.
    If you really want to learn how to get a motor running and KEEP it running then this is the place to be. We will know if you are serious about this soon enough by the questions you ask. BUT, don't be afraid to ask even a silly question. I asked a lot of silly questions when I started.
    NOW, How do you know if the carb is adjusted properly? Get back to me and we'll figure it out together. (It might just be a little dirt in the jet.)
    A lot of people use these to get to work or school, but most of those that do, also know how to fix them. I rode my last bike for two years with only a couple of flats. A friend of mine breaks SOMETHING on his bike almost every other day. A two stroke does not rate near the top for depenability. If you are looking for 100% dependability then buy a Honda.
    Big Red.
  4. Big Red

    Big Red Active Member

    Gas Cap

    Yeah, I've had that happen to me a couple of times. I'm not sure, but I've heard that the rubber gas cap seal may be on backwards. I haven't had it happen since I heard this, so I haven't had a chance to test this theory.
    Big Red.
  5. Motorized

    Motorized New Member

    It's not a matter of my not being willing to play with the engine, take it apart, etc., the problem I'm having is not knowing where to begin. What I'm going off right now is what I was told when I bought the bike, which is that it ran very well. Some people are slimeballs and sell **** merchandise, but I didn't get that impression so I'm assuming the guy was telling the truth. So, if the bike did run well (and it did run better when I first got it), then I wouldn't imagine that the carb would be set improperly.

    Since I got it, the only thing I changed is the CDI (mainly because the spark boot was worn out and breaking the circuit sporadically).

    I know it runs; it used to run. The issue here, right now, is that it's not starting at all (despite 40 minutes of hardcore pedaling) My hunch for why it's not starting is that it got flooded badly by somebody who, in bringing it to me, left the gas nozzle open (and the remainder of the gas, about a fifth of a tank, flooded into the engine). That was five days ago, I had it sitting for four, and today was when I had the crazy pedaling morning.

    My issue isn't that I'm not willing to try to figure these things out; on the contrary, that's what I've been trying to do. My question is if this flooding thing is really so common (ie not knowing how far to open the gas lever) and what the best way to clear a flooded engine is (when 40 min of pedaling has done nothing).
  6. HeadSmess

    HeadSmess Well-Known Member


    what to do.

    the engine is flooding. we know this if there is a large pool of petrol on the ground after five minutes, or when we remove the plug its very very wet with fuel.

    to alleviate the problem we remove the spark plug, hold the killswitch in so spraying fuel doesnt catch alight, pedal a few metres until theres nothing spraying from the plug hole, replace plug. (or flip the bike upside down and turn the engine over a few times...also with the plug removed...much nicer on the crank seals)

    now fix the cause of the problem. i dont have a tap at all. with good float and needle maintenance, they are superfluous. anytway. remove carby bowl, and inspect the float, and or the needle. anything that appears" foreign" must be removed (learn the art of xenophobia:jester:)

    if theres no foreigners, we check that the float isnt leaking (dunk in HOT water, watch for bubbles) or that the little float lever is bent correctly( a matter of trial and error combined with some intelligent thinking)

    ok. there is no puddle of fuel! maybe it isnt flooding at all?

    so. is there fuel even getting TO the carb? it has a screw on the bottom of the carb. undo it. open the fuel tap. a lot of fuel will come out, and continue to do so until the taps closed. good. replace screw. you may skip the next paragraph :)

    if there wasnt any fuel coming out, start at the tap, then the fuel line, then the carb float, needle and lever. get the fuel flowing, whatever it takes (maybe a jackhammer is going too far)

    anyways. the first scenario, when the fuel does get to the carb, but the engine isnt starting.... hmmm.

    at this point we start looking at the spark plug suspiciously.

    if theres no spark we return and conduct a "search" cus im getting tired of typing now :)

    basic order of things unless the problem is blindingly obvious is check fuel, spark, then start pulling things apart one by one...
    Last edited: Feb 23, 2012
  7. motorpsycho

    motorpsycho Active Member

    you mean that you bought this bike, and didn't try it out before you handed over the money?
    I would have ran it, and rode it for awhile before handing over the money (unless i misunderstood what you wrote).

    you didn't need to replace the cdi if the boot on the wire was ripped. the spark plug wire just screws into the cdi, so you could have just replaced the spark plug wire with an automotive one for a couple of bucks.
    If you replaced the cdi, are you sure that you're wiring is done well and no bare wires are touching anything?
    did you solder the wires or did you just use the push together connectors?

    as far as the gas lever, you will need to open it all the way because it's gravity feed and the float bowl will always have to stay full. if not, it will do what you experienced....runs out of gas.
    i'm putting my bet on either the float is sticking, the float is adjusted wrong or, the float is cocked sideways in the float bowl.
    when this guy deleiverd the bike you you how was it positioned? was it layign on it's side, or was it standing up?
    sometimes if you lay a motorized bike on it's side, the float will get wedged sideways in the float bowl and it will stick, causing the needle & seat to never fully close, whioch will lead to the carb flooding over.
    I don't think your issue has anything to do with the gas lever at all. I'm betting that it's internal, inside the carb, and has to do with the float.
    or the needle & seat has a peice of dirt in it causing it not to close all the way to stop the gas flowing into the carb.your float could also have a hole in it, which will cause it to fill up with gas and sink, leaving the needle & seat open all the time.
    another common thing is that the main jet will fall out, but normally that doesn't have anything to do with the carb flooding over, that has to do with the way the engine runs (or won't run).
    as your engine runs, the fuel level in the carb float bowl is constantly going up & down.
    the float bowl should remain as full as possible without flooding over, and the needle & seat regulates the flow of fuel as the float goes up & down as your engine burns the fuel.

    one of the first things you should do is drain the gas tank so it doesn;t flood over any more.
    then, remove the spark plug and turn the engine over a TON of times to get the fuel out of the engine. leave the plug out for a few days to let it some of the fuel evaporate.
    you're spark plig is probably soaked with fuel and that's probably why it won't run right now.
    then, you need to tear into the carb and find out why it's flooding over.
    once you get the engine dried out, a good dry plug and the float issue fixed, it should run, unless you're having an ignition problem.
    Last edited: Feb 23, 2012
  8. Big Red

    Big Red Active Member


    Good advice from everyone. The one thing that didn't come up is that if the carb needle was stuck open he may have raw fuel mix in his crank case, and a lot of it. If it didn't pool on the ground it may have pooled in his case.
    I've only read about this happening a couple times to people on this site, never to me, so I don't know the easiest way to check or drain it if this is so.
    And, is he talking about his choke lever or does he have a lever throttle? He says that "letting gas through is just by means of a lever". Not that it matters what type of throttle he has, but he needs to be clear about his problem so we can help him.
    Anyway, Thought I'd let him know that it might be a fuel flooded case. It can, and has, happend.
    Big Red.
  9. motorpsycho

    motorpsycho Active Member

    someone already mentioned that and suggested flipping the bike upside down to let the crankcase empty out.
    i think when he mentioned the lever, he's talking about the lever on the petcock that's in the gas tank...the fuel on/off petcock lever.
    yes it is a fuel flooded case on the way i read his posts, but the problem is....why is it flooding over?
  10. HeadSmess

    HeadSmess Well-Known Member

    i get so sick of typing but the practise is good for me i guess
  11. Big Red

    Big Red Active Member


    Everyone is telling him how to fix his carb. Thats great, But how does he drain the mix from his case. He can get the carb fixed and it still wont start with a case full of fuel and oil. I would like to know how to drain a case if this ever happens to me. Would you have to remove the engine and turn it upside down?????
    Big Red.
    P.S. Sorry headSmess, You DID say turn it upside down. I should read the post's better.
    Last edited: Feb 24, 2012
  12. Al.Fisherman

    Al.Fisherman Active Member

    Would you have to remove the engine and turn it upside down?????
    No, there are a couple of things that you can do, without removing the engine or turning it upside down. The easiest is to remove the spark plug, rotate piston to BDC, and insert a air hose in the spark plug hole and blow. This won't take but a minute or so. Another is removing the spark plug, rotate piston to BDC and let sit and nature will evaporate the gas from the fuel mix.

    Now for those that don't have a air tank. You can get a small inexpensive 12V pump. You can either use the cigarette lighter and plug it in, or install battery clips. I have two along with my big tank. One I cut the plug off and attached to clips to be able to use directly from a battery. All stores that sell auto parts should have them in stock
    Last edited: Feb 24, 2012
  13. Big Red

    Big Red Active Member


    Thanks HeadSmess. The only one that I don't understand is the "let nature take it's course and evaporate". Wouldn't that still leave the oil behind after the gas evaporates. Won't too much oil in the case cause problems also?
    Big Red.
  14. HeadSmess

    HeadSmess Well-Known Member

    not as big an issue as turning it over when the crankcase is flooded...

    theres a period between the piston port closing and the transfers opening where the only way out is via the crank seals... hence turning it upside down, and letting gravity be an ally :)

    just forcing it over works, but can ruin seals... can. not will, just can...

    so the method used is governed by circumstances and location really...

    letting it evaporate will work, a bit of extra oil never hurt anyone except whoever was sucking on the exhaust pipe... :)
  15. Big Red

    Big Red Active Member


    Thanks HeadSmess, And I assume any extra oil would sling around enough to eventually get sucked up and burned.
    And the only pipe I've ever sucked on had "some kind" of tobacco in it, although I do know some people!!! :jester:
    Big Red.