I never heard of Rotella T4 15W40 in motorcycles, the cold viscosity would scare me with a 15W tbh. It is JASO MA certified so go ahead.
Rotella T6 5W40 full synthetic is a very common oil used in motorcycles though, which is also JASO MA/MA2 certified.
So in both cases, safe to use with a wet clutch.
I had a XV1200 Virago; a notoriously hot running engine. It would cook regular oils in less than 1500mi. I ran Rotella T6 in it for about 40k miles (this was before the MA ratings). The stuff is indestructible. I got caught in Gatlinburg once, bumper to bumper traffic, 95° temps. I crept along for 45 minutes before getting out of there. The bike was so hot I put my right foot on the end of the peg to stay away from the heat coming through my boot. The bike just put putted along, no problem.
I also had a 650 VStrom later. I put 65k mi on it using T6: no problems. I did get that bike hot once as I didn't get the radiator fan hooked up correctly and got caught in traffic again and pinned the temp. Didn't seem like there was any harm to the engine (I did have a stator failure later which may have been related to the overheating).
While my Scrambler is in warranty I'm going to use what the dealer uses. After that, haven't decided, but in my experience, T6 is great oil.