Crank bearing shot - Oil injection or pre-mix XLT800

[jamidon]

I have a couple XLT800's. On my 2004 I switched back to oil injection at the beginning of the season. On the third tank of regular gas I lost the rear cylinder, compression dropped to 30lbs. Tore it down and found the crank bearing shot and shrapnel from it took out the piston and rings. First thought was it was starved of oil but upon further inspection both carbs and reeds have a healthy coating and the front cylinder and case look brand new. I am thinking the bearing wear wasn't caused by lack of oil and wouldn't the piston seized before the crank bearing and connecting rod got hot enough to take out the bearing? rebuilding with new crank and top end but trying to decide if I stick with oil injection or go back to premix. Replace with all new tygon hoses and stainless pinch clamps on all connections. Pics attached of front and rear cylinders/carbs.