I was out ridin and I had just done 5 donuts and when I got back my bike was actin funny it would idle up then down and with it settin there it will eventually die. I can't think of nothin except that I use 93 octane in it and then I suddenly put 87 so could somebody please help me out with my prob

 

The gas might be a good bet. My brother has (2) Z-400's he had a similar problem. His was the pet **** it was on PRIME!!!!!!!!!!! Might be worth checking out. He don't remember turning it to PRIME so maybe they're lose and vibrate loss. I hope this helps