I changed the oil and greased my 2004.5 500 HO for the first time, followed the instructions in my service manual. No big problem, figured out which hose was the vent and found the slit, it did take a couple of tries to prime the oil pump. I cranked up the engine then clamped the hose with my fingers held it for 20 seconds and I heard the air purge from the slit. Only real problem was trying to grease the shaft running to thee back of the ATV, guess I will have to get a shorter nipple for my grease gun I couldn't get it on the jerk.