Knock in my motor

Hey there I was surfing through this forum and found a lot of great information on these motor bikes. I have a Shwinn set up with a 69.7cc motor which i think they call an 80cc. It just started knocking and smoking more than usual. I have only had it since the end of Nov. and probably had 1 or less gal. run through it. I used the oil ratio that it called out for for breaking the motor in. When the motor is under a load it doesn't knock but if I'm just cruising it knocks at 1/4 or 1/2 throttle. What may it be? I will attach a link where yo can go and download the movie so you can hear the knock. Let me know what you think it may be. Thanks for any info. I also bought the CDI Jaguar ignition I still need to put on.

MVI_1545.zip - 4shared.com - online file sharing and storage - download

* Any help would be greatly appreciated!!

Hey there R/C Thanks for the reply. Send me your contact info at [email protected] Would like to speak with you. Maybe I can bring it by and you can take a look if your around today. You can download that link. The only reason I did it that way on a TPS site is because the file was too big. It's just a little movie clip of my bike at idle to hear the knock. Thanks....................

So I took it apart and this is what I found:

<a href="http://s866.photobucket.com/albums/ab223/hornsgalor1/?action=view&amp;current=IMG_1555.jpg" target="_blank"><img src="http://i866.photobucket.com/albums/ab223/hornsgalor1/IMG_1555.jpg" border="0" alt="Photobucket"></a>
<a href="http://s866.photobucket.com/albums/ab223/hornsgalor1/?action=view&amp;current=IMG_1565.jpg" target="_blank"><img src="http://i866.photobucket.com/albums/ab223/hornsgalor1/IMG_1565.jpg" border="0" alt="Photobucket"></a>
<a href="http://s866.photobucket.com/albums/ab223/hornsgalor1/?action=view&amp;current=IMG_1561.jpg" target="_blank"><img src="http://i866.photobucket.com/albums/ab223/hornsgalor1/IMG_1561.jpg" border="0" alt="Photobucket"></a>

Anybody hear of a bearing I can put in place of that brass bushing?

So I decided to tear it apart and take a look and this is what I found:





Anyone know of a bearing and can replace that brass bushing?