Engine Trouble New "Happy Time" starting issue - am I missing something?

Discussion in '2-Stroke Engines' started by scottyracer, Mar 8, 2015.

  1. scottyracer

    scottyracer New Member

    Hi guys, first real post on the forum - hope you can help!

    I'm not totally new to basic engine mechanics so would like to think I'm not doing anything too stupid here, but am hoping to be proven wrong. I installed the engine (80cc two-stroke, purchased from eBay) with no real issues, filled her up and attempted to start by setting the choke, pressing the tickler a few times, pedalling up to speed and engaging the clutch. The engine does turn over when pedalling with the clutch disengaged but doesn't start. I've checked the following:

    • Fuel - Tank is full with correct 16:1 break-in mixture. Tap is on and fuel reaches carb.
    • Carb - Bowl is filling with fuel. Float/needle/jet assembly all seems right. Needle is set on one of the middle notches (4 different notches on my needle). Throttle valve(?) appears to move correctly when throttle is operated. Idle screw operates correctly, currently set about 1/8th open.
    • Spark plug - After attempting to start, plug is clean but slightly moistened with fuel, not too much or too little. Tested plug out of the cylinder head and saw a consistent spark, after removing the killswitch wiring from the equation. Have tried with a different plug too.
    • Clutch - All operates correctly, engine is disengaged from wheel when lever is depressed and turns over when lever is released.
    • Air flow - filter is all clear and appears to be sucking through fine.

    It seems to me that I have all the obvious ingredients here, am I simply being impatient or is there something I've missed? I've been careful to read through many other similar threads before posting and have tried all the suggestions but to no avail. Am I not trying hard enough when pedalling or is this just a dud kit? I have another identical one available to swap parts with, but wanted to check there wasn't anything I'd missed before swapping everything!

    Best regards

  2. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Not correct.
    16 to 1 or 8 ozs of oil to a gallon is way too much and misinformation in the 'manual'
    This bad info is based on using 30 weight motor oil in China where you couldn't get 2 stroke oil.

    The most oil I would add to the first gallon is 5 oz.

    Did you mix in a separate fuel container or in your bikes gas tank?

    You may have flooded the motor, when you drop the clutch keep pedaling hard.
    you really don't want to touch the tickler unless you are filling the float bowl for the
    first time.
    If it doesn't start using the choke try with no choke.
    scottyracer likes this.
  3. jaguar

    jaguar Well-Known Member

    use a long downhill.
    pull the plug, hold it against the head, and with limited lighting check to see if there is spark while pushing the bike.
    6 oz per gallon is 21.3:1 ratio which is close to the desired 20:1
    scottyracer likes this.
  4. dougsr.874

    dougsr.874 Active Member

    Sounds like you have done about all I can think of....last resort is to check the magnet to make sure it hasn't slipped on the key, or just replace the magnet
  5. scottyracer

    scottyracer New Member

    Hmm, interesting about the fuel/oil ratio. I'm sure I've seen plenty of info from non-Chinese sources suggesting this 16:1 ratio though and they didn't seem to be having any problems! The fuel and oil were mixed in the tank, the same way I used to do my old Peugeot moped, by adding some of the oil, then some of the fuel, repeating until the desired fill is reached. I will try again with less oil though and see what happens.

    As I mentioned above, the spark is already present and consistent, I don't think that is the issue here. I've also tried two different plugs, as I read something about some plugs firing fine when not installed in the engine then not working when installed. Also it might be worth mentioning that I tried to start it accidentally with the cylinder head bolts loosened as I forgot to tighten them after inspecting the inside of the cylinder - the engine felt like it almost started this time and did warm up a bit. Obviously there was insufficient compression to keep running or produce any power though.
  6. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    If you didn't close the fuel valve on the tank some of the oil can sink to the carb
    where it won't allow starting.
    Flush oil out of the carb bowl and fuel lines with fuel mix.

    16 to 1 will start but it's not good and this misinformation is all over the internet.
    scottyracer likes this.
  7. butre

    butre Well-Known Member

    I suggest using 32:1 non-synthetic from the start, let it warm up and then start abusing the hell out of the engine with uphill wide open throttle runs for about 10 miles, finishing the tank, and switching to full synthetic. use 40:1 if you're more concerned with speed than reliability. I've been using 50:1 full synthetic lately with no ill effects.

    the whole baby it during break in thing is just lawyers talking ****. you want to run it hard.
    scottyracer likes this.
  8. jaguar

    jaguar Well-Known Member

    yeah the high performance engines are the ones that need the most break-in period and these engines are definitely not high performance, mostly because of their low compression. (It all has to do with potential blow-by at the rings)

    the higher the compression the harder it is for spark to occur. more compression needs more voltage to spark the gap. The fact that the engine tried to run when the head bolts were loose (which makes the compression extra low) tells me the ignition system is too weak. I'd replace the stator coil and put a good CDI on it.
    scottyracer likes this.
  9. scottyracer

    scottyracer New Member

    Hi again chaps,

    So the weekend is here and its tinkering time again :)

    I swapped the CDI & coil for one from another "Happy Time" kit purchased from the same seller, and drained the tank & carb then replaced with a much lighter 25:1 mix. Tried to start again multiple times, even going down a hill, albeit a brief one, but still to no avail. The cylinder case doesn't even get warm :(

    Any other suggestions folks?

  10. jaguar

    jaguar Well-Known Member

    by "coil" do you mean the stator coil at the left side of the engine?
    the ignition system is crap. You replaced crap with crap.
    other than that the only thing remaining is the crank seals. maybe they are leaking.
    lower the needle completely and set the slide stop so that the opening is almost closed, maybe 1mm open.
  11. jaguar

    jaguar Well-Known Member

    also you need to remove the shellac from the stator coil frame where the screw heads rest. that shellac prevents current flow. those 4 spots are part of the current return path for the system.
  12. scottyracer

    scottyracer New Member

    Yeh, that's the coil I swapped. When I tested the spark after that it seemed maybe a little more potent, but obviously have no way of telling how its performing under pressure. Does anyone have a good source for better-than-stock parts for these things?

    How would I test if the crank seals are leaking? I don't have a compression tester unfortunately.

    By slide stop do you mean what looks like an idle adjustment screw or something else?
  13. Timbone

    Timbone Active Member

    I'd like to know what the motor sounds like when you go to start it. It could be flooded; you could have a vapor lock preventing fuel flow. If you are getting what I call "warm run" but it won't pop and go, it is likely vapor lock in the fuel flow system.
  14. scottyracer

    scottyracer New Member

    It sounds REALLY rough, rarely you get a very slight "pop" but mostly nothing at all encouraging.
  15. jaguar

    jaguar Well-Known Member

    >Does anyone have a good source for better-than-stock parts for these things?
    check at Sick Bike Parts or JNMOtors

    >How would I test if the crank seals are leaking? I don't have a compression tester unfortunately.
    strip away the parts so you can see the seals then spray soapy water onto them and then turn over the engine. If the seals are leaking then bubbles will form.

    >By slide stop do you mean what looks like an idle adjustment screw or something else?
    yeah that adjustment screw.

    "rough" usually means too rich. take it downhill with the fuel off and throttle open to clean it out. look to see that the plug is dry. then go down the same hill and spray starting fluid into the intake. If there is some compression and there is spark then it will run somewhat. then go down the same downhill with the fuel on. (make sure the needle is in lowest position)
  16. fattirejack

    fattirejack Member

    Have you checked keyway on your magnet, it could have fallen out on assembly. You would still have spark, just out of time.
  17. Timbone

    Timbone Active Member

    My best guess: you'e got some kind of vapor lock that is keeping the cylinder from getting the fuel it needs. If your fuel line is too soft, pressure could be causing it to close. Of maybe there is a bend in your line.
  18. dougsr.874

    dougsr.874 Active Member

    Once again, check the magnet on the mag-coil to make sure it hasn't slipped or turned...will put spark out time