Diesel engine oil has been popular in motorcycle communities for decades. Shell Rotella T in particular, since it has a JASO MA2 certification for wet clutches. The synthetic T6 5W40 does tend to shear quite a bit in high-revving motorcycle engines. The conventional Rotella T4 15W40 is quite shear stable.
There are some diesel engine oils with an API SN rating, like Mobil Delvac, meant to be used in fleets with both gasoline and diesel engines. These oils will have lower phosphorus than dedicated diesel engine oils, but usually just under the maximum allowable level for the API SN rating.
As for motorcycles, the multi-use gasoline/diesel oils may be suitable for motorcycle wet clutches in practice, but they will never have the JASO MA2 rating, since the required phosphorus level for JASO MA2 is incompatible (higher) than it is for API SN. I've used Delvac 1300 Super and Rotella T4 in my bikes without any issues.