Hi, I was all mad and about to dis on Opti-2 oil. I rebuilt the top end of my bike because of a scored cylinder the end of last year. I had about 2000 miles on the zoom 80 motor. I switched to Opti-2 oil from the breakin and broke in the new top end as fast and hard as it would go. I have about 500 on the rebuild and the other day I was going wide open and I heard something happen. Lost some power and the bike became really hard to start. I figured the oil had failed and the top end was gone. Just took it apart and the pic is what I found. Inside of my cylinder is smooth as glass and slippery to feel but the plug is dry chocolate. The Opti-2 is working great, maybe so good that the compression did this because I hadn't checked my headbolts for a bit and they were a little loose. Posted this cause I really didn't think these motors had the power to blow a alum headgasket. Once again I was wrong.