Hello to everyone, i'm new here. I'm currently rebuilding gearbox on my '05 WR 450. I just got all gearbox bearings that i ordered from my local yamaha dealer (Poland). One of ordered bearings is not the same as original one. Dealer said that this part was replaced by another. I did some research and found out that original bearing (KOYO 6004 SH) can resist 10 times longer in contaminated lubricant compared to standard bearing. All bearings for gearbox have SH mark. SH stand for special heat treatment. Dealer send me standard KOYO 6004 bearing with C3 internal clearance. I have request, can someone check for me this part number: 93306-00426 and get information if it is really replaced by 93306-00423 ? I think that something is wrong, if i use this standard bearing it can broke very soon. Apologize for any mistakes in post.