Crank bearings [Archive] - Yamaha Forum : Your Yamaha Motor Products Community & Resource

Crazyhorse1

04-24-2011, 11:58 PM

I just bought a new crank and crank bearings for my 04 YZ 250.
The old bearings had 1 crank bearings with #'s 63/28C3 on flywheel side and 63/28 the clutch side and it pulls off the crank by hand.
The new bearings that were in ATHENA packaging only have the 63/28C3 #'s on both and they are press fit only.Did I buy a defective pack of bearings or should I order the 1 bearing that can be pushed/pulled off crank by hand.
Thanks any info sill help on why they came like that

rooster

06-09-2011, 01:27 PM

Don't know if you ever got this squared up, but all crank bearings should be press fit. Many bearing manufacturers are doing this, for whatever reason (I tried "All Balls" recently - same issue with the one oversize inner collar, and I threw them out and went OEM).

If your crank is within tollerances, and the bearing can be hand fitted, or spins on the crank, it's not a proper fit. The bearing collar will spin and burn the crank bearing machined surface. Then you're back to square-one needing a new crank.

IMO, use the Athenas.


Yamaha Forum : Your Yamaha Motor Products Community & Resource > Off Road & Motocross Motorcycle > YZ-F & YZ > Mechanical / How To > Crank bearings PDA : Crank bearings Crazyhorse1 04-24-2011, 11:58 PM I just bought a new crank and crank bearings for my 04 YZ 250. The old bearings had 1 crank bearings with #'s 63/28C3 on flywheel side and 63/28 the clutch side and it pulls off the crank by hand. The new bearings that were in ATHENA packaging only have the 63/28C3 #'s on both and they are press fit only.Did I buy a defective pack of bearings or should I order the 1 bearing that can be pushed/pulled off crank by hand. Thanks any info sill help on why they came like that rooster 06-09-2011, 01:27 PM Don't know if you ever got this squared up, but all crank bearings should be press fit. Many bearing manufacturers are doing this, for whatever reason (I tried "All Balls" recently - same issue with the one oversize inner collar, and I threw them out and went OEM). If your crank is within tollerances, and the bearing can be hand fitted, or spins on the crank, it's not a proper fit. The bearing collar will spin and burn the crank bearing machined surface. Then you're back to square-one needing a new crank. IMO, use the Athenas.