Kawasaki KLX 110 Dirt Bike wont idle.?

[Carlos C]

I want to buy a Kawasaki Dirt Bike 110cc. The bike turns on but it won't idle. As soon as you turn it on, it turns off if you don't give it gas. The bike looks in good shape, no body damage, tires are new. Engine does not smoke. Oil looks fine. Only problem is that it won idle. The owner said that the bike needs to be warm up first. I did just that and still did not idle on its own. Should I buy this bike? What could the problem be? The bike goes for $1700 new, he is selling his for $800 a 2005 model. Any suggestions are welcome. Thanks