Help! My Bike is smoking.

[nahman]

Hey guys new to this forum and new to motorcycling. You guys seem like a great source of info some I'm coming with questions. So lets get too it.

Allright I purchased a 2002 Gz250 from a Msf school about two months ago. It has about 8,700 miles on it.I really didn't know much about bikes (still dont) so I didnt really look it over that well. Anyhow so yeah I bought it but I didnt drive it (it was soo cold). Last month during my spring break I started riding it though. I rode it for a while with no problems. Until the second day when after I warmed her up and rode for about five minutes it started to smoke. The smoke was white, I have a horrible sense of smell so I cant really describe the smell. Needless to say I became upset, until my friend pointed out there was no oil in the bike. I figured that was the problem and added oil (didnt change the filter though). Anyway I changed the oil and thought all would be good. It wasnt. Still until this day after about five minutes of riding the bike starts to smoke. What ever is happening doesnt seem to affect the bikes performance though because I rode it all the way from the Bronx to long island, and while and smoked and stunk it didnt conk out or any thing. I still ride it around campus also. Also yeah I forgot to mention theres this black gunk on the (Im not sure of the term, im a newb) I think its the carburetor, not sure where thats coming from...I'll post pics.

Oh and one more thing I found out why there was no oil in the bike originally, the bike has an oil leak. I put in a bottle of oil like four weeks ago and its empty again. Is it dangerous to ride with an oil leak? and how can I fix it?