4 stroke engine not working

Discussion in '4-Stroke Engines' started by davidLY, Jun 7, 2013.

  1. davidLY

    davidLY New Member

    I installed my 4 stroke engine kit on my bike.

    It worked for a few minutes and then stopped and the motor doesn't go at all now?

    any ideas on what I could do and what the problem could be?

  2. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    You forget to turn the fuel valve on or there is no gas in the tank! :)

    Your lack of info and our not being physic means we have no cue? :devilish:

    What kinda 4 stroke kit did you get?

    hey, welcome to the forum!
  3. davidLY

    davidLY New Member

  4. HeadSmess

    HeadSmess Well-Known Member

    strip carb, clean every lil hole, orifice and crevice. blow out with compressed air.

    flush the tank with a swig of clean petrol.

    run a fuel filter.

    pull spark plug, check for spark, foreign bodies between electrodes, etc. maybe replace if all else has failed.

    if it has spark, before replacing carb, put a few drops of petrol down the intake. it should fire up and run for a second or two if all is good.

    otherwise, check valve clearances.

    if it has no spark, try a new plug, and failing that, get a new coil.
  5. HeadSmess

    HeadSmess Well-Known Member

    if you installed it with a 44 tooth sprocket on 26 inch wheels, quick! change it for 36 or 40! unless you have really really REALLY steep hills ;) they dont last being revved flat out for too long :(

    20 inch rims? run a 28T or so.
  6. dougsr.874

    dougsr.874 Active Member

    Did you have oil in the crankcase...these engines are usually shipped with NO oil........Also, from the pics, you fell for a real lemon.......the engine in these kits are good , but you are screwed on the gearbox....Price is not always the best buy.. By stopped working , do you mean the engine quit, or is the engine running but bike is not moving
    Last edited: Jun 7, 2013
  7. LR Jerry

    LR Jerry Well-Known Member

    You may also have a problem with a bad kill switch connection.
  8. powerstroke

    powerstroke Member

    Did you run the engine in after buying it?
  9. Big Red

    Big Red Active Member

    Looks like it was a no oil or kill switch problem. Or he's just a little slow getting back.
    Could be the carb, If he ran it without an in line filter it's the carb for sure. These 4 stroke carbs plug up REAL easy.
    Big Red.
  10. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Stopped up carburetors are the major reason the 49 CC 4 stroke motors stop running.

    A few helpful comments:

    Never use an air hose unless the float bowl is loose, as it can "crush" the float in some carburetors.

    The biggest issue is the tiny "pilot" jet, and it is located in a hard to find location. You must remove the manual idle adjustment screw [normally black plastic], and lift the pilot jet assembly out of the carburetor. Most often the pilot jet is almost impossible to clean, however a very small piece of wire [from a frayed throttle, brake or clutch cable]works every time.

    I pilot jet is so small even 100 pounds of air won't force it open.

    I suggest using Gummout carburetor cleaner in about every 5th tank of gas [been working 100%for years].

    Most of the problem is from evaporated gas, however the chips from under the gas cap can also make for a bad day.

    If the bike is to be out of use for a short time, use STABIL to keep the fuel from going bad.

    Have fun,
  11. Big Red

    Big Red Active Member

    All GREAT advice Quenton. An inline filter is a MUST for these engines. Those paint chips will get you every time without one. And the 4 stroke carb is a little harder to service/clean than the NT carbs. If it's only the low speed jet then a brake cable wire works great. The rest of it is a PITA if it gets clogged. SO, Like I said, An inline is a must.
    Big Red.