bike will start but wont drive

Howz it goin everyone I have a about a hundred miles on my bike and while I was riding the other night something made a loud noise down by the clutch. So I pulled over to see what it was and couldnt really see anything cause it was dark out. So I tried to start it back up and it fired but wont drive I can run and rev the motor but I dont get anything to the rear wheel. I want to ask and get a few options or ideas before I tear into it. Any ideas would be greatly appreciated.

hey everyone sorry I was short on info it was late and I had just walked a couple miles pushing this bike to get home. so today i pulled off the clutch cover and found my problem, it was the small gear that rides on the clutch gear. that little gear just snapped in half. Im guessing it was able to jam up enough to start but when the motor was running there was no woodruff key to turn the large clutch gear. so I guess Im gonna order a new one and get this bike on the road again, any pointers on putting the new gear in oh and also the motor is a 66 cc with a clutch not centrifical.

yhea I was amazed that I can start the thing but not ride it. its a first to me I have never been stranded to where I had to walk, but now I know.

well i found out the hard way that grease on the clutch and the small gear is now something to add to my matinence list since i put about a 50 or more miles on this thing a week. but now im checking out the plug in this thing and its really dry and has a little build up on it. the plug is the stock plug that comes with the piston bikes kit, its the one that has 3 prongs going to the electrode. the bike runs great gettin up to 30 mph on level ground sometimes 27 to 30 even on slight hills. i thought these plugs were supposed to be a little wet and looking kinda golden in color. my thoughts are to raise the needle in the carb but before i do i want to make sure thats right.