I have a 300ex and one day when i tried to start it, the bike fired once or twice and then just died [img]i/expressions/face-icon-small-sad.gif[/img] and when i tried to start it again it had no sound or air coming out of exhaust and just made a kind of buzzing sound.... upon investigation i found out the timing chain slipped off???? and i put it back on and retried to time the bike. it took awhile and i finally got it but then it died again so i took it back apart found it had slipped time and i tried to retime it again but now it wont run. has good spark, good fuel, and everthing else is in order.... can anyone help me please i need it quick

 

all i can think of is your timing is out.
see if theres any marks on the gears and try to line them up as best you can then put your chain on.
if its like a car you want it on the compression stroke.
you should get a new timing chain that one is more then likely streched.
hope this helps.