The CRM250AR was
NOT an EFI'd / DFI'd bike. It had just your basic carb.
Just click on the "history" link provided under the picture of the AR - you can find plenty of info about the "AR" part on the web.
The last of the EXP400s were EFI - though, the EXP400 that Richard Sainct (sp? - edit - I always get this wrong - I
'think' it was Jean Brucy ????????? not Sainct) - I think it was he, but I'm not 100% sure - got 5th, I think, in a 90s (95?) edition of the Paris / Dakar was alternatively reported as being carb, then EFI'd, Carb'd, EFI'd, etc etc etc.
The EXP400 used in the Nevada Rally was carbed, and was the first (public) version that basically had a CR500 based bottom end. That was reviewed / featured in Dirt Bike magazine. I think Bruce Ogilvy rode it in the Nevada Rally, and, perhaps the Baja 500 / 1000.
Brucy's /Saincts Bike:


The 400cc 2t had the same torque as the Works V Twin Honda 4t '750', with just a bit less horsepower, about 10HP less. Honda gave out something like 74HP and 70 /74 ft/lb ( or, I think, N /m) of torque. It weighed at least a 100lbs less, and used / carried, less fuel than the 4ts. It was widely held that Brucy was told to not win - instead, it went for the 'single cylinder' - or was it 'sub 500cc' class? win, and, of course, got it.
So - a 2t, nearly 20 years ago - I'd put money on it / them being able to be taken out of the Honda museum, having a few updates, and walking all over the bikes in the forefront of Dakar, today.
Then , think of what near 20 years of real development would have given us by today. Really, really give some thought to it.
Hell, I 'd just like to see a couple of people use a 300 2t in the Dakar. Louis finished on a 150. A 300, should be a bit easier to do so with.
Well, thinking on it - KTM, say, entering a DFI 2t, when they are about to finally release the
only to be released when the legislators have the gun to our heads, DFI 2t (it's perfectly understandable, they are making
so much profit from their 2 2t engine modules) is something that could happen - though, perhaps only in a fantasy land.
Oh, note the clear upper fairing - something that has re-appeared with the latest Dakar Hondas, and KTMs.
The 'Sloper' EFI / DFI engine in place:

AR workings drawings and explanation:

A patent drawing of one (there were many) version - a forward 'sloper':
And, a reverse cylinder engine:
I see various posts with people saying Honda are about to release a EFI / DFI 2t.
Honda, obviously have thousands of designs / patents, that they have explored - they are , perhaps, the ultimate ICE Engineering company.
But, Honda, since day one, have been a 4T company. Yes, the very first full Honda MC had a 2t engine, but Soichiro (sp?) himself, hated them, and went directly to 4ts. The only reason they made 2ts after that, was due to the '70s dirt bike explosion, and the need for them to
win, and, of course, get sales. Thus, the Elsinores were surreptitiusly developed as "Lawn Mowers", until they were show to Soichiro, almost as a 'faite au compli' - many here will know of this. Then, of course, after the humiliation of the NR500, the Oval pistoned, double conrod, 8valve per cylinder faux V8 ( 4 cylinders only were allowed, and 4t / any engine,
had to be within 500cc for 500cc racing), Honda brought out the Triple, then the Four Cylinder 2t GP bikes.
In every step of the 4t 'revolution' there has been Honda's hand - the manipulation of rules that enabled 4ts to become competitive = ' handicap ' rules, doubling capacity.
Honda had set in stone, that they would cease 2t production by 2007 - and that, they did. People who called themselves 'journalists' seemed to be unaware that was Hondas schedule / plan, set many, many years earlier.
I'd be stunned if Honda
ever brought out a 2t again.
But, you never know - if equivalency became a hard and fast rule throughout the entirety of racing,
And 2ts for general use became more common, thus dominating sales, they may do another CR / RS capitulation to the basic better solution a 2t is, for ICE powerplants. But Honda are at the forefront of stopping equivalency. I honestly believe that 4ts, would become / should become, redundant dinosaurs of the ICE age. Modern , naturally aspirated 2ts, have the ability to far surpass 4ts. And, even if turbo charged / supercharged 4ts re-appear - and there are several 'show' bikes / engines doing the rounds currently, those same techs can be applied to 2ts. And no, I'm
Not a 4t hater - I've more of them than 2ts. I just believe 2ts hold far more advantages / potential over 4ts, for ICE applications - in all forms of vehicles.
Oh - something I've noticed lately: I'm supremely non ' E Techy', not even owning a smart phone, but I see all these new Power Packs etc - small units that people can use to re charge 'phones / Puters, and Start Vehicles with dead batteries. Some units, barely over the size of a pack of cigarettes / an Ipad Mini, can reputedly start a car / truck, many, many times over. I can see that as the sort of thing that many would find useful - not the least those who have an E Start only bike. If I were in that position, I'd certainly own / carry one. They are cheaper than having a decent quality lead acid spare battery, let alone a LiPO, or whatever those trick, lightweight batteries are that people upgrade to.