NR750?? = I'm taking guesses at these so when this bike came out and the results started coming in, I used to call the bike, "Not Ready.'
CB = Citizens Bike (originally) RR = Race Replica seem correct, or city bike. I'd question citizen and use City, imo.
ZX..who knows? A 14R is called a ZZR over here, don't know what that stands for either. ZX and again, who knows, but looks like Z=big-one like the first one was Z1 as in top model. 14R is still R for race with the tree settings options for rpm limiter, rpm staging, etc. RR is euro, R is western?
In the GSXR range the R is for Race. Suzuki has used GS for years but again no idea. Same here but sounds like I've heard Grand Sport eXperimental Race.
I had a Yamaha DT250MX....(Dirt Track 250 Mono Cross)... I'm going to say, Dirt Trail 250 (take the lights off for) MotoX.
I guess some letters actually stand for something and others are just model range/catalogue designations. JMO. Yes, once the product has a long run, it's back to refinement, the demand of the public (Busa-GL) sort of following, aka, factory bread and butter bikes.
ATC - All Terrain Cycle
GL - Grand Luxury
KX - Kawi motoX
WLA - [War] [Low-compression] [A=740cc] ww2 Harley engine code letters.
Tormenting the motorcycling community one post at a time