Motorbike as a BOV, help please.

[Tonka]

Now this may be a subject I'be put a little thought into over the years.
I go to the Rat and Survival bike and trike rally every year. There are a lot of weird and wonderful machines that are cool as Fonzies fridge, but the real survival machines tend to be little simple MZs and the like.

Diesel bikes are cool... I go to the diesel bike rally now and again, but they are all quirky non standard machines. If you want to survive on one, it's best that you were the one who built it, and have a big stock pile of spares. You pretty much need to be a mechanic with facilities to produce bio diesel for this to be an option.

An off road or on road bike? this isn't so important as it is with cars. I have ridden plenty of road bikes off road, you will only need to do some green laning type riding, not motocross. A good set of road bias all terrain tyres would be a good bet. Size and weight are more important than suspension and comfort.
It's good to have a smaller lighter bike, they are easy to handle in all conditions, and to drag out of trouble. It does depend on how big you are. To me a 400cc is a tiny bike... a 125 would be great for some, but you would be limited on load.
I would recommend a bike between 300 and 600cc. Smaller does work for some people.

Simplicity is key. In most cases avoid water cooling, that is a whole other area to go wrong and makes the bike a lot harder to work on. Although a KLR600 or Armstrong 500 have done OK for the military.
A single cylinder engine is good for ease of repair and weight, but a twin will still carry you along with one cylinder not firing.
Obviously no fuel injection or fancy electro wank... I mean I refuse to have any of that on a bike I commute on, so no way do you want that after doomsday.

Range is not important. One Jerry can bungeed on add 500 miles to the range of a bike... it won't to a landrover.

If it is likely to be hostile out there. It is best to ride in groups. Wire across the road only gets the first in line (you should be armored enough to get up again) and then the others have your back. Bikes are indeed vulnerable on their own.

My Harley probably wouldn't be the best survival bike due mainly to size... I have taken it off road but it wheel spins like a bugger and is hard to lift. My 350 Enfield Bullet would be OK though, they do a trials version of it, it goes anywhere my old jeep would go, at 80mpg, 300 miles on one tank, easy to lift, kick start so works with diff battery etc.

So be it Kawasaiki, CZ, Husqvarna or whatever. The key really is reliability, ease of maintaining, availability of parts and the right size you.
Just avoid Italain... their bikes don't seem to be able to survive a ride to the shops on a damp day, let alone the Apocalypse!