my buddy had the two inner crank bearings on his 5mm seize after less than 30 hours. brand new pro built motor. he sent the crank back to builder who said it would be covered because it must have been faulty bearings. 950.00 crankworks bill and months of down time was the end result. gotta love this hobby, this is why i stick with stock cranks, available and cheap and last longer. live and learn, i learneded to leave stroker cranks to pro with connections in the industry, us little guys never get the hookup.