Hey I’m the new owner of a 88’ K100 and i’m wondering what regular maintenance i should be doing. I plan to go through and change all the fluids so i have a fresh start, but i’m wondering what the fluid is that goes into the drive shaft? and another area by the rear wheel? And if there’s any other regular maintenance to be done please let me know!

I use Motul 3000 20W50 mineral oil and my Ks seem to love it. Also filter I think is HiFlo HF163.

Both of these are used in Hondas and the filters are available at Honda dealers.

Gearbox and final drive use 80W90 but need slightly more than a litre to do both. Again, Honda dealers are good for it.

Strictly you need to lubricate drive shaft splines and its not difficult. Of course, Honda dealer again!

Coolant change, best option is to slacken the hose at the water pump and not to open the drain plug. For refill you can move the tank back and raise the front, rad cap is under front right. You will need to put bike on to side stand to get the air out when refilling it.

Now I would go and polish the bike in detail, not to make it look good but to be getting in to inspect all the nooks and crannies and see whats there, looking for any leaks etc.

There is more, brake fluid change....DOT4 from .......Honda dealer.

There are lots of little things like vacuum pipes and vacuum caps [dirt cheap but cause bad running], issues in the fuel tank [fuel pump, filter, pump mounting and damper etc] rotting out fuel lines [cheap enough from a ...Honda dealer], dirty injectors, usually cause by sitting with bad petrol, rotting out fuel lines or missing fuel filters.

I would start by riding the bike a bit and getting a feel for it. The forum is great for knowledge and swapping parts or part sources.

One thing I usually do when I get a K bike...put in a new clutch cable.

The engine oil, the transmission/rear drive oil, and the DOT 4 brake fluid to which Olaf refers can all be purchased from any Walmart, too. Because your Brick has a dry clutch, auto oil is what you use. There's a K100/K75 shop manual in the Tech Page index. It will help you with procedures. The Tech Page link is in the Portal.

Be certain that you use a GL5-rated Hypoid gear oil in the gearbox (800cc +/-) and final drive (250cc). I use 80W90 mineral or 75W90 synthetic, depending on my budget at the time, and availability. GL5 is a rating that defines how much sulphur-based friction modifier is present in the oil, and is intended for heavily loaded gearsets such as "differentials" and final drives, with helically cut gears that have potentially greater side loads. 

As for engine oils, there are so many varying opinions on which brand/type/viscosity/mineral vs synthetic, & etc.

It's correctly written as '88, not 88' when referring to the year, BTW. Otherwise, it's an 88 foot long motorpickle.