I finaly fired up my bike(2002 kx250)and it sound horible.It might be that I havn't heard a bike in al,ost a year but is like-bang,bang,bang,ping,bang,bang.lol.the bang's sound like a normal bike firing but the ping sounds like it comming from the silencer.this is only at idle(havn't riden it yet.)and also it is making a very hard vibration it is crazy.you can see the rear fender vibrating.what could this be?I hope it's nothing major.please work with me I couldn't find a better way to describe it.oh ya it was like +5 celcius when I tried to start it.thanx alot for any help