BMW Locking Oil Filler Cap - Good Grief

[sloopy_farklehump]

I bought the locking cap for piece of mind. I've put about 1000 miles on the bike since it was installed a few weeks ago and now it won't come out. It just spins and spins. Are they not designed to be removed when the bike is cold?

[DJ Downunder]

That's very odd...I've had mine for years without a problem...is it the one with the rubber flap?

Is it the bit that it screws into that's turning..or the key in the hole?

DJ

[sloopy_farklehump]

Yes, it is the one with the rubber flap. The key is taking hold and the whole unit is spinning and spinning and spinning...

[Philbie]

any chance of a Pic?

DJ - where did you get yours? from Ringwood BM Mechanic?

[DJ Downunder]

It's a genuine BMW part..so Moto One or Southbank will have them in stock...and well worth the 20-30 bucks...here's a couple of pics.

The key is shown here..attached to the little bottle of oil.. http://members.optusnet.com.au/~djp1/mypic2565.JPG

DJ

[sjbmw]

Are you pressing down as your turn?

[Airman]

I have heard of this happening with the custom caps, the ones with the Roundel. It's probably a poor installation. The internals are loose and the valve cover will have to come off to tighten them. (Not a very tough fix)

[sloopy_farklehump]

Well... the service mgr at the dealership told me the same thing happened to him and after fixing it many times he has gone back to the plastic cap.

This would be much easier to explain if I had photos. Essentially the locking cap consists of 3 pcs. The key, the metal cap and a plastic ring. The plastic ring snaps into the cyclinder and is held in place with a tab that sticks into an indentation in the cylinder. The tab, obviously, prevents the ring from rotating. In my case the tab popped out.

The fix is to gently pry out the plug ( the ring comes with it). Remove the plastic ring from the cap and reinstall it.

[Airman]

That sounds pretty, ah.. simple. The custom ones I think are aluminum and have a nut on the inside of the valve cover. Is this an expensive piece?

[JONBOW747]

Has any one tried the non locking cap with just a screw driver slot ?
Thanx J.B.

[12bar1]

I had the BMW locking cap for about two years and the cap worked fine but the plastic insert started leaking. I replaced the O-rings then the entire assembley and it still leaked. then I switched to the SW-Motec cap with the metal insert, no more leaks. I had to remove the valve cover to install it but it really was not that big a deal. It was a little more expensive than the BMW part but it is a much better fix IMO and it still sort of locks, you need a hex wrench to remove it.

[ProductUser]

Here's the problem with the SW-Motec oil fill cap: It has two allen screws that embed themselves into the valve cover. After prolonged use (opening and closing the cap), those allen screws may turn due to the soft material of the valve cover. You'll discover this when you think the hex cap never seems to tighten. Once this happens, there is a possibility that metal shavings may find their way into the oil passages due to the allen screws turning within the valve cover.

How do I know? It happened to me. Perhaps I'm too much of a big gorilla and tighened this thing too much. Who knows, but it cost me a new valve cover. The standard BMW locking cap, with the plastic insert, has worked great for a number of years. Yes, it will leak, but replacing the o-rings every year or so isn't that bad.

This is just my opinion.

ProductUser

[sloopy_farklehump]

Airman Posted: Tue Aug 01, 2006 10:09 pm Post subject:

--------------------------------------------------------------------------------

That sounds pretty, ah.. simple. The customs ones I think are aluminum and have a nut on the inside of the valve cover. Is this an expensive piece?

It was about $40

[Boxer04]

I have the genuine BMW filler cap. I had the same problem when I first installed mine over a year ago. It was so tight that I thought I was putting too much strain on the key to remove the cap. Then the whole cap started turning and I could not remove the cap. Lifting the key up simply removed the key. I eventually levered the cap out without damage.

What happened? The seal between the 'o' ring and the seat was too tight and the seat (held in by an 'o"ring) started spinning. The seat has a small locating lug and the undoinmg motion caused this lug to come out of the machined groove in the valve cover.

The "o" ring looked thicker than the satndard "o" ring so I placed them side by side. I then took a micrometer to the "o"ring on the BMW cap. It is marginally thicker than the normal "o' ring for the standard plastic oil filler cap (but marginally smaller in inside diameter.

My solution was to replace the 'o' ring that came with the BMW cap with a standard filler cap "o" ring. It could be a little tighter but has been working fine to date.