Last night i was riding my 300ex and i was topped out and all the sudden it just bogged down and had no power just kept bogging down til it quit and it wont start back up. it still has spark and gets gas. im really not sure what went wrong.please help ASAP.

 

If it has spark and gas...............the next thing to check is compression.

 

its got compression

 

How much?

 

its got good compression still

 

Could be something as simple as a kill switch or wire came loose or shorted. Could also be something as bad as a timing chain broke or a valve broke. Hard to say. Take a look at all wire before you panic and start tearing the motor apart.

 

well you also need air, the other i can think of are, fuel are the spark plugs wet, if not the fuel is not getting into cylinder, the next would be spark, have you checked to see if the timming is still in specs., value adjustment, are the values adjusted right,an last spark plug try a new plug it could be blowing out (a spark plug can fire when in open air out of cylinder but not fire when in the cylinder under compression. just some thoughtsgood luck hope you get fiquried out

 

check your air filter if its clogged it would starve your engine. anlso to the coment before it the valve got chipped the compression would be down.

 

gay tether cord switch was screwed up got her fixed a while ago