went south with rider for the past week. Mixed 3 gallons race gas with 2 gallons 93 pump gas 32:1 bell ray h1r. He rode alot, lol, burned 20 gallons through practice bike. Problem solved. Stock yz250 will not last on pump gas if ridden aggressive. Met another guy who had same problem and fixed same way.
bike is awesome, just run min 100 octane fuel.
thanks for replies
I hope this helps some others.