Motor runs for a few minutes, then locks up, oil pump bad??

[VJR021]

Just rebuilt the top end on one of my bikes and it ran great for a few minutes... After that it locks up.

If I let it cool for a few hours, it will fire up again.

I'm thinking oil pump and bottom end rebuild now?

 

[geeessfore]

Rings to tight or crankbearings going