Last winter I had the Adventure Motor Trike conversion installed on my 2010 Goldwing.
This conversion has grease zerks on both of the drive shaft U-joints. Thats the good news, the bad news is in order to grease the front u-joint, you have to remove the drive shaft. You have to be certain that you are installing the drive shaft exactly the way you took it out. As I understand it, the u-joints have to be aligned perfectly or you will have problems.
The local dealer said they would charge $60 to lubricate my driveline. I am going to try doing this myself. I am sure that if I had a hoist it would be a lot easier. Life is a lot more difficult when you are a cheapskate like me.