My K1100LT uses oil. It has only about 24 k miles on the clock.  At highway speeds it may need 1/4 quart after a day's riding.  My 1985 K100RS never required a top up between oil changes.  Is this normal?
Second question: one of the YouTube videos makes the claim that the fuel tanks secured by those irritating two clips at the rear are dangerous and that the clips should be removed and thrown away.  The idea is that in an accident they can be the cause of fuel tank failure and resulting fire.  Is this a credible issue? 

Per BMW, the allowable oil consumption is 0.151 liters per 100 km - which works out to the insanely high figure of 2.55 quarts per 1,000 miles.

As someone who has owned over 20 Ks my experience has been that it varies with no apparent correlation to model or even riding behavior.  In other words - quite random.  Sometimes the same bike will burn almost no oil and sometimes it will burn half a quart every thousand miles.

Some of them also have the unique ability to "hide" oil.  The oil will be somewhat low and then the next time it's checked (when cold) there will be more oil in there. Lord knows how or why this occurs.

My advice:  Check it at least every 1,000 miles and top it off to a level somewhere between 2/3 and 3/4 full in the sight glass.  (Although I usually "cheat" before I go on a long tour and fill it up to near the top in case I forget about checking the oil when out touring.)

I usually carry spare oil with me when out touring.  A 20 oz Coke bottle is ideal for this as they won't leak in your luggage and are easy to pour from.

I'm pretty sure that BMW put the tank clips on there so that in event of a getoff the tank won't go flying off of the bike thus the tank staying on the bike decreases the chances of the tank flying off and spewing gas all over.

I think most people who leave them off do so because they're a pain to install.

BMW sold over 200,000 bikes with those clips on the gas tank.  I think if they were somehow dangerous that a recall might have been warranted - but there never was one.

Have you run a compression test on your engine?  I suspect you may have stuck rings from extended periods of idleness.  My first K100RS  16V used a fair bit of oil when I got it.  I was only getting about 400-600 miles to quart of oil.  Compression tested good with 145-150psi across all four cylinders and there were no external leaks.  The bike had sat for at least two, maybe three years before I got it.  I rode it for three years and 16,000 miles and over that period the consumption went down to about 700-900 miles per quart

Last winter I put a quart of Marvel Mystery Oil in the crankcase another quart in the fuel tank and over the winter while it was parked in the garage, I would start it up and run it for 10 minutes once a week.  In the Spring, the oil consumption was down to a quart in 1000 miles.  The new owner ran the bike over the summer with the MMO in the oil and at the end after putting another 3500 miles on it told me it only uses a 4-5 ounces every 500 miles now.  He told me that he only used a total of a quart over the summer.

Regarding the tank hold down clips, I was involved in a pretty violent accident with my K100 about a year ago.  The bike was hit by a car and flipped several times destroying every body panel, bending the frame and tearing the fuel tank off.  One of the clips appeared to let go, as the stud was still on the tank and the clip was gone.  The other stud was ripped off the bottom of the tank right at the welds, and was still in the bushing on the frame.  The stud that was torn off did not leave a hole, and the tank only leaked a small amount of fuel, which came out of the lines. At the time of the accident I would estimate that there was about 3 1/2 gallons of gas in it. 

If it really bothers you, you could cut part way through the studs so with a large impact the post will break off without tearing the welds.

On some model bricks the tank clips play an integral part in securing your side covers (K75s). If you omit the tank clips what can and does happen under certain circumstances is when you hit a speed bump or large road bump the tank will jump up at the rear. This is dependant on a few factors speed, size of bump, amount of fuel and tightness of retaining pegs in the rubber bushes. The result on the K75s is that the side covers make a bid for freedom which can prove an expensive exercise in the long run.

Regards Martin.

MartinW wrote:The result on the K75s is that the side covers make a bid for freedom which can prove an expensive exercise in the long run.

Regards Martin.

It never occurred to me that could happen but you make a good point.  That could also happen on a standard or C model K75 since those use the same side covers as the S.

Duck a mate lost a few side covers and couldn't work out why. And he refused to believe it was the lack of tank clips which he described as a pain to fit and unnecessary I was following him one day and he hit a sizable bump and I could see one of his covers lean out shortly followed by a bid for freedom. I stop and picked it up and upon realizing he had lost me he pulled over. I presented him with his recaptured cover but he refused to believe that the lack of clips had caused it. In order to convince him to reinstate the clips I took him down to a local shopping centre and had him drive over the speed bumps. They didn't unclip every time and he was about to argue that it wasn't anything to do with the clips when on hitting a speed bump they both made a bid for freedom.
Regards Martin.

My K1100 takes 1 liter oil in 5000 km.
Has 195000 on the clock
Never fill it up more than half on the glass, still I know where the end of the throttle is (and my driving licence if I keep doing that )

I think there may be some value in riding the bike more - perhaps with some high detergent oil - before I do any further hand-wringing over the oil consumption.  Clearly, the machine was idle a great deal in the past, so a stuck piston ring or two is possible.  I have not done a compression test, but I will when things warm up around here. I do know that the engine does not lack for power.  Not one bit! The engine in this K1100LT is also smoother than the engine in the  K100RS I previously owned. It's a very satisfying experience to twist the throttle.
Duck, your comment about vanishing/reappearing oil seems completely unbelievable unless - like myself - you have personally experienced that mystery. I have no idea where it sometimes hides, but hide it does   
I've decided to retain those pesky two clips at the rear of the fuel tank, just where the factory put them. I'll do my best to avoid any suddenly stops/get-offs that may threaten the tank's integrity. 

If you lay up your bike for the winter, I strongly suggest adding a quart of Marvel Mystery  Oil to the crankcase and running every week for 10-15 minutes.  Marvel Mystery Oil is well known for it's ability to free stuck rings. 

I asked about the compression test, but be aware that good compression doesn't necessarily mean the oil control rings are working.  It does indicate that an attempt to free the oil rings is worthwhile.

BR2 those pesky clips can be made easier to live with. I made up a hook with a finger loop to make removal easier the loop resides under the seat under a piece of Velcro. Another inmate attached cable ties to his "C" clips and trimmed the ends to a handy length. And I made some "C" clips out of some scrap tin with longer pull out tabs as a trial they worked quite well. I was going to remake them out of stainless but it got put on the back burner, as the hook works really well.
Regards Martin.