Depends on the use. Only one that springs to mind is that it is short for 'bobbin' A little rubber cylinder shape that protects the motorcycles fairing in the case of an accident.
bob - crash bobbin. Many available.
In context, would this make sense?
Super Bikes
cubic centimeters
Scott and Moeller
it stands for "CLOSE RATIO"
Because they're two tired! LOL
I think that b.o.b. Stands for baby on board
bubble stand
Bob
Bottom of Buggy
big wheel 85's are around 89cm
It doesn;t stand for anything, it is just the model. its pretty much a code, so motorbikes can be easily identified.
4