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

[cstreit]

Is that for a line-bored case? ...or a ground crank.

Can't seem to find out a reference...

Chris

[john walker's workshop]

Measure the OD if you have them in hand. Rubber band the #1 thrust halves together and mic them. You would notice 0.10 thou oversize, or thereabouts. Usually stamped on the bearing too.

[cstreit]

I’m getting 64.96mm

I think that makes the STD OD and undersized ID yes?

(It’s for a 3L which has 65mm mains.

[john walker's workshop]

Sounds like it. OD oversize is not common. Expensive too.