I just swapped for a 2005 HD Heritage Softail Classic, had 23500 miles. I will be changing oil in all three holes at the 25,000 mark. I dont know what oil has been used in the bike in the past. I have been told that Amsoil can clean out seals and cause them to leak if not used from the git-go. I tend to think it will be OK to use Amsoil at 25,000 but would like to hear from you all.