That may well be, but without any governing body to dictate those rules, it would be very easy to build the VLR slightly quicker than the KA.
However, it looks like the KA more than held it’s own this past weekend, so at the moment I’m not too worried.
Hmm, the KA and VLR have different port timing, different reed size (KA is larger) and a different carb *
Min head volume could be different, but I wasn’t able to find it on the KA100 fiche.
Perhaps those decisions were from a reliability standpoint.
Granted the carb I think is close or identical to the KA’s (US version) but a different model number.
Another thing, the details given in the fiches varies wildly. There’s no standard (that I can tell) that specifies the required information. So each fiche covers different details.
There’s a squish dimension on the KA, but it’s absent from the VLR.
Min head volume is shown for the VLR, but not KA.
Etc etc
Incidentally, I spoke with Dave Larson from TAGUSA yesterday. For 2019 they will be adding a mixed 100cc class which at this point would include at least the KA, VLR and X100AC (Which I think they renamed the X125, despite being 100cc 
)
My observations from running a KA (my first experience with any of these “new” 100 air-cooled engines) at Rok the Rio…
I ran Masters. The top 5 were all on the KA, and by the end of the weekend, we had created a bit of a gap to the VLR’s. Now, to be perfectly honest, I have NO idea if that came down to driver / chassis or engine. What I do know is that early in the weekend, we were closer and I wouldn’t have known who was running what, but (personally) as we refined the chassis and I got better behind the wheel, I got faster and faster. Also, the top-5 all had more “team support”, while the VLR’s tended to be smaller true “privateer” efforts. My gut tells me that they could have run together, but because the KA is a “more tested” package, most people were on the KA.
In the Senior class, again, most of the karts were running the KA. BUT, the guy who led most of the final was on a VLR. So, I’d say that the VLR is certainly capable.
I believe that as time passes and more people become familiar with the VLR, that you’ll see a pretty even split between the 2.
At this point, my only question is how the IM engine will fit into the mix.
It sounds like they have a few pre-ordered, so we’ll be able to see what the preformance is like.
However, knowing the IM guys, they’ll have done their homework, so I’m sure there will be parity.