I just bought my xt250 as my first bike after getting my permit about a month ago. It's 2013. At 100 miles I dropped the oil and changed the filter. As a small woman I've also installed lower links to drop the height a bit and raised the front forks a bit. It now has about 224 miles and I've started noticing a clicking or ticking sound coming from just under the gas tank. I notice it mostly when at about 1/4 open throttle. It doesn't do it when I'm going at a steady speed at about 1/2 to 3/4 open throttle. I also notice it when going too slow wen at too high a gear and the bike vibrates like it wants to die. I can't do any one thing to reproduce the noise but it happens all the time at varying speeds. 

Any ideas what this could be or what I should check? 
Also: when I hug the bike with my thighs I notice I can feel the difference in vibration when it makes the noise, so I know its more than just plastic.