80cc 2-stroke Gas Leak

Discussion in 'Frame Mounted Engines' started by MotoredTed, Dec 7, 2007.

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  1. MotoredTed

    MotoredTed Guest

    Hi everyone

    I recently bought an 80 cc 2 cycle bicycle to motorized bike kit from Kings online. My main complaint is the carburator keeps leaking gas I think the main problem was the round gas float bowl gaskett,it is not leaking at the present time ,but every time I think it is fixed it starts leaking again and the screws are just about stripped from tightening,the chokeside screw is a little hard to tighten straight on.

    Has any one else had a problem of this nature. Also I have a question about 2 cycle oil, I thought all 2 cycle oil was synthetic and just used 2 cycle oil from Home Depot :shock: for my first half gallon,and synthetic 2 cycle oil was recommended. The bike seems to be running ok so far---so have I done any damage ? Should I change to synthetic does it really make a difference ?


  2. mickey

    mickey Guest

    My Kings "80" also leaked. I adjusted the float and the problem went away.
  3. fetor56

    fetor56 Guest

    There are mineral and synthetic oils...the synthetic oils costs much more but their better(IMHO) in-so-far as the ratio of petrol(gas) to oil can be increased,making them a more cost-effective method of lubrication.
    By the sounds of it u have partially run your bike in with mineral based oil which will do NO harm...the harm usually comes from over-reving/over-heating a new engine or having the petrol to oil ratio to lean.
    When in doubt(unless u know otherwise) follow the manufacturers recommendations for the correct ratio.
    If u have the finances it's probably better to switch to an all synthetic oil but it's not essential.
    Last edited by a moderator: Dec 7, 2007
  4. Egor

    Egor Guest

    The fuel in the float bowl at proper level does not come up to the gasket edge, the fasteners just need to be snug. If it is leaking the float level is too high, or the stop valve is weeping by. It sounds like it is doing this just sitting, not running. I have one like that, I just for now turn off the gas at rest. Have fun Dave
  5. dancycle

    dancycle Guest

    Putting some gas resistant RTV around the gasket and screws on that will keep gas from leaking, but make sure the carb is still oriented properly.
  6. I also am having a leak problem, but I would say mine is pretty bad. Im losing a significant amount of gas from the tank, but every morning I come into my garage and replace the paper towels underneath the bike with new ones because they have become saturated with gas/oil with in one day. I would say it is a constant leak every 10-15 seconds. Its becoming quite a smelly and annoying problem. Would getting a new carb help at all???
  7. cooltoy

    cooltoy Member

    Think of your carb like your toilet. It works the same, if the ball or float is not adjusted properly, the tank will overflow. You just need to adjust the float inside your carb by bending it so that the fuel level stops just before it reaches the gasket. Do an advanced search-without a doubt, you will find your answers.
    It could also be as simple as a bit of dirt so clean things up while adjusting the fuel level
  8. spad4me

    spad4me Member

    I also have a kingsmotor engine.

    My gas tank was contaminated with rust, oil, and gooey ****.
    Flush the tank out.
    Remove the tank and throw out the fuel.
    Clean the petcock filter.
    Install an inline fuel filter.
    Clean the needle and seat.
    Make sure the fuel jet is unclogged.

    I have spent too much time solving carburetor and fuel delivery problems on this engine.
    Next time thatsdax for me!
  9. Uh oh...

    Beautiful weather today in the suburbs of chicago, but as soon as I hopped on my bike and let out the clutch, the area between the top end of the cylinder cover and middle main finned part of the motor start squirting gas/oil all over my bike and shoes. My guess is that the engine is flooded?...right? but why did it do that, and I didnt have time to empty the carb or open anything up, so I am letting it sit over night. will that do any harm? Maybe I'm wrong, can anyone tell me what going on

    thanks mbc'ers
  10. cooltoy

    cooltoy Member

    It sounds like you blew a head gasket and should not be a big deal. it may just need to be tightened. Do you ever do that as they need to be checked about 5 times when new?
    I don't think it is flooded and even so, it should not come out the way you say it did.
    Just so you know the "finned part" as you call it, is the cylinder and the top part where the sparkplug screws into is the "head". In between these is a "head gasket"
    Hope that helps, now go out there and see if the 10 mil nuts are loose, if so you could try to tighten them, in a x pattern the way you would with a car tire so that the head is not warped. I would take the head off to have a look at the gasket but you sound unsure of yourself
  11. cooltoy

    cooltoy Member

    I don't know how to do the link thing but if you look up a thread started by "blompad"
    and find "torque on head bolts" you may find what you need
  12. I have taken the cylinder and piston apart before, so I'm not afraid of opening things up, but refresh me of what the gasket is and where?