For this riding season I changed the entire fleet over to HPL MATV 10w40. So far, the only oil change I've done is on the Honda 450r. It barely holds 1 qt, so I change it every 10 hours, give or take. No samples sent in yet. A Honda Pioneer sample will be sent in for sure. Last year the 15w40 T6 sheared out of grade after 650 miles. Not sure on the hours, but it's my old mans, and he drives it on fire-roads...like a old man.