ah I got ya now!
I never tried putting rpm ball ends on my yokomo, but did try on my kyosho and just assumed the yokomo's were the same ball stud diameter as the kyoshos. The yokomo must be the only metric car with the same 'balls' as imperial!
so to the original poster, YES the rpm ball ends will fit the yokomo.
part numbers are
RPM73372 for short black,
and
RPM73392 for the longer ones. You can get them in different colours too.
dont have a bmax with me now, so not sure if you need short or long ones, or both.