This crank bearing failure is only in 2003 and later twin cams. In 2003 the switched from the timken bearing to a straight roller bearing and this has caused the problem. Although this bearing failure CAN happen in any '03 and later, it is usually found in bikes making 100+ horsepower. I know of failures in motors within a few thousand miles, and others in 30,000 miles, there just isn't any sure way of knowing where or when it's going to happen. This bearing can be exchanged for the older style timken bearing though, and several are choosing to do this. It requires splitting (obviously), and machining the cases for an insert sleeve and a new timken bearing. Zippers is one of the shops doing this, as well as is T-man performance and other speed type shops. The SE bikes that come with the 103's and all 103 crate motors made after 2003 are "ALL" succeptible to this bearing failure. Though those left in stocklike condition shouldn't have too much to worry about as they are fairly far from the 100 HP map, but SE103 bikes, that have had remapping, performance exhaust, and aircleaner exchanges fall into the 'more likely' catagory. Truelly there just isn't any way of knowing. I built my 2003 HD twin cam motor out to 124" before this was known to be a problem, and though it makes 125 HP and 140 lbs/ft TQ I rode it for 12,000 miles without any trouble. It is now torn down getting the timken exchange. On the other hand I know of one bike with under 100 HP that didn't last even 5000 miles.
One thing to consider, if this bearing does go? It can destroy your motor, crack your cases and cost a whole hell of alot more than the $400 for the exchange. If you are in the danger HP zone, you just have to decide if you like to gamble or not. I know I don't and with the power I'm making I was no doubt in the red zone. At least my worries are over now.
zigz