I crossed the Rovuma above MDP using the locals and their small boats without any problems a few months ago with my girlfriend.
I paid $50 for a Dr650 and 2 passengers but it's fair to say I'll be a bit harder with a BMW. On the Mozambique side the river bank is very steep and you'll have to rely on the locals to lift your bike on and off the boat.
A few points to note.
Don't take any shit from the guys operating the boats.
When you arrive tell someone what you'll be paying and wait for them to agree.
Get a boat with a motor, you'll need it if the tide's out...
That sand is a bit of a killer but I did it 2 up so you shouldn't have any worries,
hopefully you'll be running tkc 80's on your bike.
It's not easy but it's great fun...