What is the crank bearing size?? - Mongoose 20" Mode 270 Boys Freestyle Bike

Mongoose back in the day were pretty good bikes and can only buy them in Bike shops. Now they are mass produced in China and sold at Amazon, Walmart and Target. That said, when they are produced in mass, the quality of assembly goes out the window. They arrive in boxes the size of big screen TVs and assembled by a store employee who has some mechanical ability. But I digressed, what I mean to say is that part of the assembly at the factory, they rarely grease the bearing, at least by a lot, thus premature failure of crank bearings. Proof of this are videos of people buying Mongoose bikes from Walmart and disassembling them to find hardly no grease in the bearing cups. As for bearings, the crank is a one piece from the photos, very common caged bearing set.

Almost all Mongoose models use the standard BSA 68.
I would write a question to them at:
http://mongoosebikes.net/mongoose-bmx-bike/20-mongoose-mode-270-v2-freestyle-bmx-bike/
This bearing should not fail during the normal life of the bicycle, unless the rider weight is over 80 Kg.