The service manual says change the oil every 600 miles but I'm doing it every 1000. This seems to be what most 450L owners are doing if they're not racing.
Ive seen lots of oil diagnosis at 1000 miles (not racing) and seems fine. The service intervals in the manual are the same as the 450R, and the L model is a lot tamer so personally no qualms increasing it slightly.
The service manual says change the oil every 600 miles but I'm doing it every 1000. This seems to be what most 450L owners are doing if they're not racing.