Saturday I was riding around all day. Towards the end of the day, At about 30mph it starts to kinda make a slight clanking or clunking type sound. It feels like its between my feet. It doesnt affect the speed of the bike or its handling. after about 40mph it goes away and under maybe 20 it doesnt exist. I plan on taking it to the shop as I have no experience with motorcycles and have only been riding for about a week and a half. Any ideas as to what it may be?