Main bearing 72-3429 0.25mm UST What is this?

[cstreit]

Realized I may have better luck here.

Trying to find out if this bearing is for a line bored case... ...or a ground crank. can't find a guide to help ID it.

Thanks!

[KTL]

Chris I believe it's a 3.0 SC or 3.2/3.3/3.6 main bearing (they all have the same main size) for a crank ground 0.25mm undersize. I have a bunch of old bearings in a box on the shelf and they have 72-3429 STD on the back of them. I've only opened up 3.0 SC or 3.2 Carrera engine cases and therefore i'm certain that's what the old bearings are from.

Undersize is same OD as STD and the ID is made thicker to account for the ground crank. Oversize is the opposite- ID is STD and the OD is thicker to account for the specified line bore.

[cstreit]

Originally Posted by KTL

Chris I believe it's a 3.0 SC or 3.2/3.3/3.6 main bearing (they all have the same main size) for a crank ground 0.25mm undersize. I have a bunch of old bearings in a box on the shelf and they have 72-3429 STD on the back of them. I've only opened up 3.0 SC or 3.2 Carrera engine cases and therefore i'm certain that's what the old bearings are from.

Undersize is same OD as STD and the ID is made thicker to account for the ground crank. Oversize is the opposite- ID is STD and the OD is thicker to account for the specified line bore.

Thanks. Thats my conclusion as well. What I was hoping for was a definitive indication based on the markings on the bearing rather than measuring bits.. 0.25mm isn't much and I didn't want to get it wrong.

I'm assuming thats what the "UST" is but I can't find any reference confirming that.