Have a look at this guy on YouTube.
https://www.youtube.com/watch?v=HShbaC9ORSoOnce you get this video up there'll be a heap of links to other tutorials that he's done. It's all relative to stuff you might need to do on an R65. The only difference is that he's usually working on older BMW boxer engines (or airheads). The principal should be the same.
I've seen many of this guys movies; specifically this one, synchronising Bing CV carburettors, and fork rebuilding to name a few. Lots of other topics of interest too.
Engine oil change is to be done whilst still at normal operating temperature every 7,500 km (5,000 miles) or every 6 months. If the bike is ridden only for short distances, or outside temperatures are below 0 degrees Celsius (32 degrees Fahrenheit), change oil every 3 months or after not more than 3000 km (2000 miles).
If the oil filter has to be changed, remove it before draining the oil. Filter to be changed at 7,500 km.
DO NOT FILL HIGHER THAN THE TOP MARK ON THE DIPSTICK!!!
Total Oil Content for my 1985 R65 is 2.24 litres (4.0 Imp. pints, 2.4 US quarts) plus 0.25 litres (0.44 Imp. pints, 0.26 US quarts) if the filter is replaced.
Inspect gearbox oil level every 7,500 km (5,000 miles). Change the gearbox oil whilst still at normal operating temperature every 15,000 km (10,000 miles)
Oil content for the gearbox is approximately 0.8 litres (1.4 Imp. pints, 0.85 US quarts) Fill to the lowest turn of thread in the filler orifice.
The last time I kitted out both carburettors so they were all new inside, they lasted 12 years before the diaphragms began to leak again. Not sure how many miles that was, but I know the bike was ridden around Australia prior to that. I cleaned them with petrol. No special cleaner needed because I replaced all of the jets. Assuming that the engine is running reasonably well, the main thing I check out in the carbs are the diaphragms. They tend to get very thin around the top edges and therefore begin to split. I just bought a complete carburettor kit for my R65 and it cost about $350.00 AUD from BMW. You might get the kit cheaper from Bing. The cost is insignificant to me because I know I'll get another 12 years before they need doing again. Although expensive it's best to do the entire kit. You won't need to open them up for a long time.
To sync the carburettors when you get them back on the bike, see Chris Harris`s tutorial on YouTube. Â
That'll do for starters. If I keep going I'll be here for hours.