For anyone one looking to upgrade the cam on their XR600 or 650L, make sure the oil pump is primed and oil is flowing to the valve cover before finishing the job. I went through 2 cams and several rocker arms learning that the oil pump in these BRP’s won’t self prime if you drain the oil and disconnect the oil lines like I did. I found several other folks went through the same problem, some replaced their oil pump, once I self primed it then it flowed like a geyser. My biggest mistake was following the step by step procedures that Hotcams offered on their website. I did contact them hoping they could add this info and maybe the next poor sap wouldn’t have to waste a couple hundred dollars learning this lesson. Doubt they will so I’m posting it here in hope someone down the road can avoid the same fate.