For me, cam lobe wear starts about 1/8" from the nose, across the nose, and then down the closing ramp no more than 1/4 inch. I have noticed on most of the lobes that have cracking and flaking on the sides, also have the bad lobe, leading me to believe as crap flakes off the side-o-the-lobe, it ends up on the bucket, and kills the lobe. This was on a set of 425/415 cams. I was running 65 lb springs, which I understand should be 55 lb springs if I was to run this cam/spring combo on the street... but I didn't know.
I put about 2,000 street miles (on the bike) on the bike, and almost all the intake and exhaust lobes were gone. After the bike broke a valve off at Mojave, I measured the clearances... one of my cam to bucket clearances was >.100".
The bike dynoed at 225 hp when fresh on fireman Jim's dyno, and then year or so later we dynoed the weekend before Mojave and the bike dynoed at 220 hp. I thought the cause of dropping 5 hp was because on monsoon rain coming down while we were on the dyno. I remember sitting on the bike (with it running) and me saying WTF?, this thing is Fing clattering bad! Lessons learned.
The next set of cams are 445 / 415 which came off a busa that ran on the salt a couple years in a row, it must have had very low miles on it. The exhaust cam is fine, however the intake has both #1 lobes degraded just a bit, but enough for me not to run them after dumping yet another couple thousand into the motor. I am sending the cams to Web for repair.
I'm thinking from now on I will not start a high lift motor that has sat around during the winter without putting some KY jelly on the lobes/buckets.
So what the hell, Smokey burnout !
Daveeed