How many miles do you have on your Trike/Bike. What is considered high mileage. I have a 2005 Ultra Classic/Lehman with about 26,500 miles on it. I bought it with 24,500. It had always been serviced at the dealer and had all the service that the manual called for (25,000 service ect) done. He used the HD synthetic oil but he did the oil changes every 5,000 miles as the manual says. I don't want to run it that long before I change it out, around 3,500 miles. I am using Amsoil 20W-50. I do have all the service records. Hopefully It will go much much more.