Knocking?

A friend of mine has a 80cc(66cc) flying horse with around 300 nmiles on her. As soon as it starts it makes a horrible knocking sound, the wierd thing is it goes away about 3 minutes after it starts? The motor accelerates normally. I thought maybe it just needed extra time for lubricating, but if you run it till it goes away, then shut her down and re-start her again right away, you have to wait another 3 minutes for the sound to go away. Confused, I told him I would like him to buy another motor, and rip this one apart to see what is up. Anyone hear anything like this before?

I went for the wrist pin, but did not need to go further than removing the head, blown to pieces, the head gasket. Thanks bike guy joe for your thoughts!

BiMoPed said:

The aluminum head gasket was blown to pieces???
Do you have a pic?

Click to expand...

I will try to get you a picture of the head gasket by tomorrow night. I should of posted it right away, could not believe it. I think it was cause the head and cylinder body do not completley lay flat on one another. Gotta love chinesse machinest. Just so you know it was a "Flying Horse" the motor was manufactured in late 09. It also had clay clutch pads? anybody ever see these before?