Changing the engine oil on F650GS is a little bit more complicated than on your car, or other motorbikes, however, it can be done.
Oil changing is done in 4 steps:
Here is a step-by-step instruction.
In the middle of the bottom of the crankcase, you'll find a SW24 bolt. There's a similar bolt a little more to the front, holding an oil pipe. This one leave alone. The bolt you have to loosen, has something like "magnetico" printed on it. Place a receptable under the bike, and losen the SW24 bolt. Attention, oil may be hot! There will drain a small amount of oil, appr. 0.5 l. While the oil is draining, clean the bolt, especially the magnetic part of it. Install a new seal ring (the big copper one from the kit). After oil has drained, replace the bolt and tighten with some 50-60 Nm.
The oil filter you'll find behind the front drive chain sprocket cover (where "650" is printed on). Remove the sprocket cover (3 bolts). Now you see a round cover, appr. 6 cm in diameter, hold by another three bolts. Behind this cover is the filter. Remove the three bolts. Place a receptable under the bike. You also may put a piece of cloth on the engine housing, just below the round cover. Before pulling off the cover, you should be aware of some 100 ccm of oil spilling out! Are you? Ok, pull off the cover. You see, an awful filth ... Ok, pull out the filter. Another small amount of oil will spill out. Clean the filter cover, replace the O-ring with the one from your kit, and clean the awful filth ;-). Moisten the O-ring inside the new oilfilter with a drop of fresh oil, and insert the filter. Moisten the O-ring of the filter cover with a drop of fresh oil, and mount the cover.
Looking at the oil tank from the left, you'll see two bolts and two clamps. The upper (torx) bolt (1) and the clamps (2) hold the tank, the lower (Allan head) bolt (3) is the draining bolt. You might to loosen this bolt a bit first. Now remove the torx bolt and the two clamps. Pull the tank sidewards, and tip over a bit. Hold a receptable under the draining bolt and remove it. Once all oil has drained out, fix the oil tank, replace the seal ring of the bolt with the bigger one of the left copper rings, and install the bolt. Honestly, I have no idea what those two small seal rings being left are good for ... Maybe for the old F650. Anyway, added them to my stock.
Now it's time to fill the new oil into the tank. Be careful with the 2nd liter, attentively
watch the level. The tank will hold appr. 2 l. If the tank is full, but another
0.3 l of new oil is left, put on the oiltank cap, and start the engine. Watch the
oil level through the glass on the front of the tank. After some seconds of ideling,
you'll see the level sink. Switch off the engine, and fill in the rest of the
oil. Put on the oiltank cap, start the engine, and let it idle for one or two
minutes (officially until the radiator fan starts).
As mentioned before, some seconds after starting the oil level will sink.
After those one or two minutes it will rise again. If now the oil level is
in the middle of the glass, everything is fine. If you prefer a higher oil level,
you may add some 0.2 l.
Look if everything is dense.
... replace everything you have removed before ...
Pictures will follow ...