Main bearings

[Epic_88]

I did some checking around but I can't seem to find the answer I'm looking for.
I picked up a 05 busa that was rebuilt, the crank was replaced/ main bearings replaced and the bike ran, but it made a high pitched squealing noise. So I pulled the motor and broke it down, there where some tiny bits of metal in the oil pan but not much damage down from what I can see.

The mains looked alittle off to me though, parts of them are shiny, does that show wear on them or would that be normal? (he said he ran it for maybe 30mins) I've only rebuilt dirtbike motors, and like most dirtbike motor completely blow when they go.



I'm gonna take it to a local engine builder to get them to check the roundness of the crank and such, but I figured I'd get a heads up on it.

[sixpack577]

Those look worn

[Kiwi Rider]

Looks to me like incorrect clearance crank journal to bearing surface, insufficient oil gap causing rubbing, high pitched speak is most likely the result of this issue.
Measuring the crank and identifying the bearing sizings will reveal a lot!

[Texas Tarnation]

Looks like someone missed there crank size lol, you might be ok on the crank and need new bearings. A set of Micrometers goes along way, and no not calipers or a scale lol!

[202mphbusa]

Green paint on thrust bearing ? Is that on the wrong side? Or am I looking at it wrong in the picture?