is cam2 purple 50/50 with pump gas about that same as vp u4.2 except the oxidation

i know its not the same, but is it anywhere close? or is there any other combination of fuel or a different fuel that will be fine on the motor and not as expensive?

a different fuel that is ok in my bike but not as expensive

i talked to the guy that built it and he said it had to be vp u4.2. but its expensive. i have to run it because of the lead and oxygenation. i was told i cold get away with no oxygenation but would be best to have leaded fuel. i asked about high octane aviation fuel and he flipped out. but if it comes down to it ill just have to knuckle up and stick with the u4

its a 2007 crf250r. high compression piston and head work done by pr2. im still trying to figure out what work was done.

what effect does lead have on the motor?

Tetra ethyl lead(TEL) was added to pump gasoline in the past for two reasons. First, it is a very effective octane improver. Second, it "padded" the valve-to-seat interface to retard valve recession. Prior to the unleaded fuel age, most all-iron engines had the seats cut right into the head. They would eventually get hammered out when running unleaded. When lead was phased out, manufacturers began installing hard seats or induction hardening the integral seats.

Those are the good things about TEL. The bad is that it is responsible for more engine deposits and leaves toxic lead everywhere between the chamber and exhaust tip.