1989 FLHS up keep
Even though the last time I took her out everything was smooth should I still check my transmission & forks oil levels? I'm just following a step by step guide from 2 manuals I have but I worry about little details that go unmentioned or if my book is just trying to shove H-D products down my throat

Can I use my regular 20W50 oil for my tranny or should I get part no. 99892-84?
Just bits of advice on what to check, how to check it & when would be greatly appreciated. I used to get all my work done at the shop(tune ups, oil changes, all the simple stuff) now I want to slowly start working on it my self with basics. Like properly checking basics, oil change, & just looking for natural wear that can occur during storage.
Any help or advice will be very appreciated just trying to get off to a good start. I want to start taking care of my baby myself. I've put 23,000 miles on here in 3 years without leaving my state & being pretty broke. This year I'm looking to take some trips but not until I get some basics down on case i run into trouble on the road.








