How much oil do I need?

[Droopy Dick]

I've now put on around 600 miles on my new (to me) 1150GS.

In that time, the oil level has fallen (it had only done 2700 miles when I bought it).

The sight glass now shows the oil to be half way up the glass rather than at the top.

My question: how much oil do I need to put in to bring it back to the full mark?

And, is regualr 20W/50 oil that I use in my Saab OK? Just regular mineral oil with viscosity modifiers.

I take it that fully synthetic high-performance oil such as I use in my Toyota Supra Twin Turbo would be wasted?

Any help appreciated.

 

[wessie]

The sight glass now shows the oil to be half way up the glass rather than at the top.

My question: how much oil do I need to put in to bring it back to the full mark?

And, is regualr 20W/50 oil that I use in my Saab OK? Just regular mineral oil with viscosity modifiers.

Don't put any oil in. Half way up the glass is ideal. You know it is neither too full nor too empty. The boxer engine does not like to be overfilled - the excess ends up in your airbox via the engine breather.

IME 200ml of oil will bring the level from the bottom of the glass to the centre. Don't be alarmed if the bike uses half a litre of oil per 1000 miles for a while. Mine did up until the 12,000 mile service. Now it hardly uses any at 24k.

Your 20W/50 mineral oil will be fine for a top up. For a complete oil change I'd use a 10W/40 as it is should be better for the engine when starting from cold.

 

[carbold]

The difference between the MAX and MIN mark on the sight glass is about 0.5 litre. I always keep the level halfway though.
You are right about mineral oil, keep using it until 15k miles when the oil consumption will start dropping. Bear in mind that BMW suggests API SF, SG or SH. Viscosity 20W-50 is OK with outside temperature > than -10 °C.