Just finished installing engine on bike...But wont run =(

Discussion in '2-Stroke Engines' started by mac2flip, Mar 27, 2007.

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  1. mac2flip

    mac2flip Guest

    Hey everybody!

    I just finished installing an 80cc chinese engine on my mountain bike. The problem is, it wont stay on. I start by going on top of a hill for quick speed then i release the clutch. The engine turns on but it starts slowing down so i keep pedaling while i pull the throttle. You could hear it rev while i pull the throttle but it still slows down...and then it dies...cause i would be too tired from pedaling trying to keep it on.

    I've tried playing with the mixture screw from 1 turn to 4.5 turns. Same thing. I also removed the kill switch cause i was worried it couldve been the culprit.

    So does anybody have suggestions? This is stressing me out cause i just finished it but now it doesnt work :sad:
    I just want to shoot myself! hahaha

  2. woods39

    woods39 Guest

    turn off your choke

    turn off your choke
  3. mac2flip

    mac2flip Guest

    Re: turn off your choke

    Yeahh...it's kept open... in the middle... i tried fully open and fully closed going down hill too
  4. jeffspeeder

    jeffspeeder Guest

    did u turn the gas valve open? and did u connect the wires right?
  5. mac2flip

    mac2flip Guest

    yeah it's open... and black to black and blue to green right?...hmmmm... i took apart the carb and put it back together and fooled around with the chain and made it tighter... i havent tried it yet cause it's 1020pm already but hopefully in the morning a miracle would happen and it would work hehe.

    I tried mounting the bike on a car jack lolz, and then peddled with my hands but when i release the clutch it just doesnt turn on...i guess i'd have to pedal with my feet with a lot more force... and that's when i gave up cause i'd have to balance on the jack.

    But anyways, i'll try again tomorrow.

  6. jeffspeeder

    jeffspeeder Guest

    sounds like u got it connected right im not shure just try to pedal really fast and let the clutch out and it should turn over enough to start
  7. woods39

    woods39 Guest

    Re: Just finished installing engine on bike...But wont run =

    turn mixture screw all the way in
  8. foyeburger

    foyeburger Guest

    undo the gas line at the carbarator and turn the pet cock on to make4 sure that yu are getting gas out of the tank if you are the put back on the hose make sure gas is going into the carb the wires should be black to black blue to blue and white wire elecrical tape it up to make sure its not touching nothing. screw in the idle screw all the way and then back it out 4 turns make sure that on the carbarator that the slider is in correctly so that it seats all the way down take off the air filter to make sure by looking in the carbarator when you pull the throttle does the slider go all the way up and all the way down if it does then put on the air filter and try it again just some stuff to try seems to me your white wire is htting and grounding it out larry ca
  9. foyeburger

    foyeburger Guest

    Motorized Bicycle Starting and Operating instructions: Friction clutch model:
    1. IMPORTANT: PLEASE READ: Gas and Oil Mixture for Fuel ratio
    The engine is a 2 cycle design, therefore, a gasoline/oil mixture is necessary. During the break-in period (1st 4 tanks of fuel, the ratio is 18 to 20 parts gasoline to 1 part 2 cycle oil. After the break-in period, the ratio is increased to 20 to 25 parts gasoline to 1 part oil. The engine crankshaft bearings are lubricated from the oil in the gas mix. A rich break in oil mixture ensures bearings will not cease during engine break in period.
    !WARNING! Remember safety first: Wipe up any spilled fuel. NEVER fuel a hot engine or smoke while fueling. This could result in sudden fire, personal injury. Always move your motorized bike at least 10 feet from any fueling area before attempting to start it. Never leave the tank fuel cap off after fueling as rain water will contaminate the fuel and cause engine failure.

    2. Open the fuel valve. Small lever pointed down with fuel line is in the open position.
    3. Depress the small round cap plunger, ( Tickle button ), to prime carburetor. Located on left side of the carburetor next to the idle adjust screw. One or two times is enough.
    4. Lift choke lever to the upward position. This is the small lever on the right side of the carburetor. All the way Up the choke is on. All the way Down the choke is off. Move progressively downward to off position during engine warm up period.

    Starting procedure for Lever Friction Clutch Models:
    6. Pull the handlebar clutch lever inward, to disengage the engine from the rear wheel.
    7. Pedal; (down hill if possible for first start) A mid frame bike wheel stand is helpful to start the engine in place.
    8. Let out the clutch lever all the way out and continuing to pedal. The result is a direct engine hook up with the rear wheel via chain and sprocket and the engine will now start spinning, Pedal until motor starts. Accelerate slowly at first.
    9. Twist throttle to increase speed, reverse twist throttle to decrease speed. To stop, disengage clutch and apply brakes. To accelerate, pedal and release clutch while opening throttle.
    10. Adjust choke to the smoothest engine running position.
    11. After warm up push choke lever all the way down. If engine races too fast, or too slow, pull clutch lever and lock in the notched catch, stop and adjust engine rpm.
    12. If the rpm needs adjusting, turn the idle adjust screw (left side of carburetor) in or out slowly to obtain the proper idle speed of about 1400 rpm +/- 100 rpm To correctly break the engine in, Do not exceed 15 mph or 30 min. continual running for the first 50 miles during engine brake in. Engine will develop more power after break in.
    13. To stop the engine, push Kill switch and turn off gas valve at tank. Turning off the gas will prevent fuel from being siphoned from tank. Warning Note: Never leave the tank gas valve in "open" position" when engine is not running or the bike is in storage.
    14. After or before each ride check all mounting fasteners, including head bolts, axle and brakes.
    15. Warning Note: Engine lock up or piston seizure due to improper gas / oil mixture will not be covered by factory warranty. This the responsibility of the owner / operator to make sure the gas and oil is mixed correctly.
    Last edited by a moderator: Dec 15, 2015
  10. mac2flip

    mac2flip Guest

    Hey larry, i'm going to try it all over again from the beginning. Hmmm now that u mentioned it, it might be being grounded...because when i clutch it while the motor's on before it dies, it doesnt stay on. I'm going to electrical tape everything all the wires including the CDI.

    wish me luck lolz
  11. jeffspeeder

    jeffspeeder Guest

    give it 1 and a half turns
  12. mac2flip

    mac2flip Guest

    THANK YOU!!!

    I took Larry's suggestion that it might have been being grounded. So what i did was looked at all the wires and insulated them all. Re installed back the CDI, checked the sparkplug clearance (it was a little small so i made it bigger), and set everything back to default and made a little prayer.

    I went into the alley went down the hill let go of the clutch, and vrooooooooommm!! frankenstein came back to life...

    so lots of ThankS to everyones suggestions and from being extremely helpful...i love you guys!

    Going to take pictures of my ride soon.

    Thanks again, i gotta go, gotta go, cruisin!!!
  13. gone_fishin

    gone_fishin Guest

    now, that's what i'm talkin' about!

    MBc rocks...great job, guys 8)
  14. mac2flip

    mac2flip Guest

    yes you guys rock!!!

    but shitty thing was it stopped working again lolz... it was working fine...then i was going down hill... so i was just rolling...when i got to the bottom, it lost power and i tried playing around with the skrew and the choke but it wouldnt want to start... i then had to walk up this big ass hill and got to my work so i ditched it there.

    when i was playing around with the skrew... 1 turn, 2 turns, 3 turns, 3.5 turns, 4 turns.. well one of them... and i felt a little stutter..like a little pull but then it just shuts off...

    my bike has the same symptoms as it had when i found out about it being grounded... so what do guys think it is this time? is it being grounded again? or is my carb settings incorrect. is it my cdi malfunctioning? damn...i dont know anymore...i keep on thinking of new things... like maybe it's the clutch put some grease haha..but i dont think it's that.
  15. gone_fishin

    gone_fishin Guest

    oops, guess i spoke too soon :/

    ok, you're sure all electrical connections are well-insulated from ground & each other? plug-cable all the way seated? plug gapped to .030 and clean?

    that said, it sounds like fuel to me...you might have to take the bowl off and make sure the float/needle are working smoothly. be on the lookout for debris while you're in there.

    that's my guess, it'll work out 8)
  16. jeffspeeder

    jeffspeeder Guest

    dam i hate it when problems like this happen and its not even my bike its still frustrateing. but ya like i said give the idle screw 1 and a half turns dont choke the motor make shure the wires are connected right gas valve is open ALSO MAKE SHURE THE BOLTS ARE ALL TITE!!!! :)
  17. mac2flip

    mac2flip Guest

    Hey!!! yeah it is reallyl frustrating..especially when it's new!! like getting a new car and finding out that sumthings wrong...but guess what???
    i woke up in the morning and had an epiphany... or something like that which made me cut the white wire smaller... now it's like about an inch long or so... and then i got home hopped on the bike and vroom... its back to life again... really wierd... cause yesterday i insulated all the wires and i was pretty sure that it wasnt grounding at all!

    But thanks again guys...especiallly audidog...which made me think twice about the the wires when you wrote

    "ok, you're sure all electrical connections are well-insulated from ground & each other? plug-cable all the way seated? plug gapped to .030 and clean?"

    Now it's breaking in time!!

    Later guys!