lol!!!!
i had a similar problem with my 125 and it was embarrassing riding in town coz the noise was loud as hell....well i thought it was and i kept thinking that people would think "that guys bikes making a funny noise" as if i hadnt realised.....!!!turned out to be a goosed chain,a couple of rollers were very stiff and when they came round the back of the sprocket they kinda yanked(cant think of any other way to describe it) making a loud noise.....
anyway hope you get it sussed out in time to get out and about...if its any consolation my nc30 is off the road until further notice...notice being mot!!!!!hopefully early nxt mnth :D