24-01-12, 09:42 PM
Might be worth whipping the sprocket cover off and have a look at the sprocket and chain and clear the crap out from inside it, also have a look at the retaining nut and washer as these can give bother on these bikes. As Grahamm says give the wheel a spin with your hand and see if anything shows.
If you worried about falling off your bike, you'd never get on.