Coming from the 4speed grom to the 5speed, it's an improvement but not in all of the ways you'd wish.
Immediate changes that I recognized is the low-end torque. The thing moves even when it's bogged down; throttling in the wrong tall gear will still allow acceptable acceleration compared to the previous 4speed engine falling flat on its face. Even with in the tallest 5th gear and only going 40mph or so at 3800-4200 rpm, you can feel it pull pretty well when laying on the throttle- this is felt throughout the entire gear set. 1st gear feels shorter, while it may not actually be much shorter, it FEELS that way because of the engine's low-end torque that it has now. I off road my groms and it seems I was often slipping the clutch around sketchy obstacles for the sake of finesse but now, I can just bobble on the throttle lightly in 1st with confidence that I'm not going to stall it and have immediate go-go power even when idling down low at 2-4 mph. Pretty great.
Shifting overall is great, it seems to be more clanky as far as feedback from the transmission actuation felt by my foot and heard from my ears. From a stop, shifting from neutral to first, all the way onto fifth and back down again to any gear is confident.
What is not confident what so ever is finding neutral- it seems to be about the same as when my previous 2017 Grom was new and under 1000 miles on the clock; finding neutral had me laughing at myself often, especially when wearing some boots with no "feel" feedback. This new 5 gear seems to be even harder, there seems to be TWO hidden neutrals or even hidden 1st gear positions. It wouldn't seem that way and would be 100% comparable to the 4speed "finding neutral" phenomenon but the added dashboard gear indicator makes it extra confusing because it itself can't find neutral sometimes. Even when I KNOW it's in neutral, the dash will show "-" or sometimes I miss neutral and go into first, the neutral light isn't on but the dash still says "-" but it is in 1st(ish, it goes forward, but there's still one more down-click available in the shifter.) So, ultimately the only issue I am having right now is reminding myself to ignore the gear number indicator when finding neutral and only pay attention to the neutral light, otherwise, the gear number indicator does exactly what it's supposed to do.
I'd love the CT125 with the 5speed and torquey motor- owners say the 4speed is already quite torquey, wonder what improvements can be had on that platform with these changes.