For us, the name "Enduro" is used there. "Trail" is also another name for "Dirt," which tends to apply to off-road bikes that aren't street-legal.

I've hear the term "Allroad" used of the bikes of that category.

To make it more complicated: Supermoto bikes
Wikipedia link

Off-road motorcycles with street-racing rims/tires

Categories in French are already not so well defined, but their translation in English is probably not good.

It may be "sport" instead of "sporter" indeed (it is the case in the French version: "sportive").

"Trail" is a bike which can be used on both road and off-road, I am not sure that the name is the same in English
http://fr.wikipedia.org/wiki/Trail_(sport)
It seems to match the "dual purpose" category then.

I am not even sure if that "All-Terrain Sports" is supposed to be off-road or not... we really need some bike experts to help here

I never really paid much attention to this before since I don’t recall ever having processed any Off-Road motorcycles, but I am now a bit confused by the available categories to select for Bikes. In particular, I wonder what is the difference between “All-Terrain Sports” and “Trail”.

Also, I am unfamiliar with the term “Sporter” and wonder if it should be renamed as “Sport”. I had previously overlooked this category since I thought it meant "Sportser" which is apparently a specific type of Harley. I searched for “Sporter”, and it does not seem to be a proper term for motorcycles. “Sport bike” seems to be the preferred usage for ones like http://www.imcdb.org/vehicle_148229-Suzuki-GSX-R.html

It seems that Wikipedia uses a three category system of Street, Off-Road, and Dual-Purpose. (Scooters and Mopeds are still their own category) http://en.wikipedia.org/wiki/Motorcycle#Types_of_motorcycles
I wonder if a similar system would be more appropriate here as well? But then again, I guess that would introduce the problem of how to handle all of the ones already on the site. And since we are not on the Internet Movie Motorcycle Database, I wonder how much attention and effort should be paid to this subject?