If you properly shift without the clutch you will not harm the transmission. It can be broken just as easily with the clutch as without.Always use clutch also, don't wanna replace broken parts constantly and broken tranny parts can get expensive. I want my XX to live longer.
I use the clutch most of the time, and I'd like to think I have very quick reflexes and it would be fairly close if I were timed btwn using the clutch and not if I have to shift in a hurry. The only time when I dont use the clutch is when I am doing distance wheelies with anything, and I always use it going from first to second. I don't want to be that A-hole that hits his rev limiter and have the machine go from 1st to neutral. But to also look at it, a lot of PRO TRUCK (tractor trailer) drivers and even small pick-up diesel drivers hardly use their clutches as well. IDK, I like my toys to be nice, so I treat them how I'd like a lady to treat me most of the time.