Engine won't turn over when pedaling

[crowvise]

This is exactly like the problem I was trying to (unsuccessfully) articulate back in November and motorpsyco tried to help me with.
I will might try the boy go fast, heavy metal (hammer) head banging solution first. But any ideas on how much banging might be too much? I am fearful of breaking the clutch plate. Therefore, I say MIGHT try it first.
As for breaking open the engine, I am fearful of many things, as I am far from a mechanic, yet I am mechanically inclined(beep! Beep!). My primary concern is that in the past, while doing my first build, I recall reading that many times when opening up an engine, little ball bearings have a tendancy to fly out all over the place.
So my first Q? is what , if any, is a good way to prevent this?
My 2nd Q? is how to properly reinstall them if this happens and how many of them are there? So I will know how many to look for.
3rd Q?: are there any videos of this procedure (the one GearNut described) being done?
PLEASE HELP

 

[crowvise]

oops...

I had one too many barley pops and thought I would have to open the motor casing.
I did gearnut's procedure(as stated in post 12) today and HAPPY MOTHER LUVIN DAY!
Not something I experienced in my first build.
So the engine turns over, but no torque. Still I am happy, happy, joy, joy over this latest development. I've had the thing sitting since mid or late oct., tried to explian the problem (unseccussfully), and though many attempts were made to help, my discription of the issue must not have been articulated well enough. Or maybe GearNut didn't read my post .


I'm guessing my lack of torque is an exaust issue and or air leak...
thanks GearNut.



The truth is easy to understand once it is discovered.
The point is to discover it.
~ Galileo Galilei

 

[Johnny mac]

So I'm kind of new to this motorized bike trend. To start, I bought the bike already built off of craigslist. I was told the carburetor needed cleaning or replacing. Now I've read that these carbs are a piece of Chinese crap! So I intend on getting a better one but for now I cleaned it up. But it didn't seem like it needed cleaning. Instead everything else started to break. My guess is the person I got it from may have crashed it. The throttle snapped and the bearings broke on the rear tire. I fixed these and got it running.

I've had a few problems with it since but at least got it running. I even used pipe tape around the the carb pot to the engine to try and stop any air leaks. But only reach speeds of about 30 kmph on flat ground. I'm not sure if that's normal or not.

Anyways here lies my problem. I had it working for about a week now. Today I decided to go for a ride. I was heading out and it started out fine. I reached a downhill and decided to keep it full throttle. I reached about 60 kmph and all of a sudden I heard a loud pop. I looked but nothing seemed amiss. The engine kept going so I figured I misfired. Then as I came uphill the bike slowed and the engine would not Rev. I had a few more pops. Now I can only get started going downhill at about 20kmph. It seems like the throttle is working still because it tried to start but won't fully turn over. I'm really not sure what the problem is. Please help!!

My first thought was magneto coil fried but it starts up at 20kmph. It just won't idle. I don't think its spark plug since it does start at fast speeds and still misfired. It is hard to pedal when trying to turn over so I'm guessing compression is good. Maybe clutch isn't working right. There is also some oil , thick black/brown, coming from engine head. But I don't think that is the problem. Can someone please point me in the right direction. Thanks.