83 750 Maxim Secondary oil change.

Hi all. Ive recently picked up an 83 750 Maxim. My first bike, but I'm not new to turning wrenches. I keep hearing about secondary oil on shafts driven bikes, but can't find any on mine.
I know how to drain the fluid in the rear diff, but is it a separate drain plug or is the secondary oil drained with the final drive oil. Help?

 

I have no clue what you're talking about. I have never heard the term "secondary oil."

Many (but by no-means all) shaft driven bikes do have a second oil plug for the bevel gears (middle-gear) at the rear of the transmission, so perhaps that's what you're being told about.
I do suppose that some people might call the final drive (see the final sentence of this post) a secondary drive.

On your machine the middle-gear oil drain plug is inaccessable without dropping the exhaust. Fortunately there isn't any need to remove that plug on a regular basis. The oil contained therein is small in volume, and does get mixed with the rest of the oil in the sump. Just drain your oil from the main sump plug and carry on.

BTW the rear diff isn't a differential. No spider gears, only one output shaft. It's a final drive, and wants gear oil, just like any 90º gearbox (or diff) wants.

 

This is what I'm referring to as a secondary oil change. Maybe it isn't the proper term. I didn't know if my Maxim had this or not, but I guess not.

 

^ that is why Youtube videos are not always the best source of model-specific information, or even general information. (his advice to over-fill the gearbox is just precious. No wonder he sees evidence of oil weeping from it)

The middle-drive (may be called secondary drive by Suzuki) on the XJ series (and to my knowledge most other shaft-driven motorcycles) does not have a seperate gearbox. It is lubricated by the engine oil.

I think Suzuki went that route (the secondary gearbox) because they were planning on having that engine available in a chain-driven motorcycle as well as using it for the Madura. IIRC their intent was to compete with Honda in the V-4 market (Magna, Sabre, Interceptor), which meant that they would need to design the engine to have more than one drive option.

 

Thank you for the help! That was exactly what I needed to know.