Upgrading units after a battle

[Mobhack]

Then you'll be out of luck - SP does not have the concept of "a pile of disused bikes/motorcycles" that can be temporarily dumped and picked up later.

Units require crew, or they are considered destroyed.

So about the only way you could really do this is to have a motorcycle with the requisite lift for the larger section, plus some crew which are simply ignored in the formations total. Similar to in MBT with APC where the commander usually dismounts as part of the section - sometimes 1 crew is deducted from the vehicle crew to balance, but usually not, if the section needs 8 and the total should be 7+1. The extra crewman (or carry capacity) is neither here nor there, except to the occasional rivet-counter type of nit-picker, whereas the dismount team size is relevant.