Oil fill cap vibrating/lifting

[Trobinson]

'96 R1100RT.  I'm posting this to verify my thinking as I haven't dug into it yet, but while doing some other checks on the bike I had it running on the centerstand and noticed the oil filler cap was lifting up.  I'm guessing I have a restriction in the crankcase breather tube.  Am I correct or is there something else I should be looking for?

 

Tom

[AndyS]

Hi Tom.

Have you checked your oil filler cap and the filler cap housing has the correct O rings?

Also, have you checked the sump under the air filter for oil

Is your bike 'using' oil?

Are you getting much oil being blown out of the filler cap?

My first thoughts is that you don't have an engine problem but possible a filler cap issue. These bikes do push air around inside, but so long as everything is OK, they don't have much pressure.

[Michaelr11]

Check this diagram.  There are two o-rings that seal the oil filler, one for the cap and one for the insert. Parts 5, 6, 7 and 8.  Make sure that the insert is in position.

 

https://www.realoem.com/bmw/enUS/showparts?id=0418-USA-03-1996-259T-BMW-R_1100_RT_96_0413,0418_&diagId=11_1704

 

[Trobinson]

There's no oil in the airbox, but I haven't checked the drain for it.  I do use some oil but honestly I'm not sure how much.  My riding has been sporadic and I haven't kept tabs lately.  The engine does have 180k on it so some use is expected.  The filler cap housing was replaced a couple of years ago so it should be correct, but I do appear to lose oil there.  Over time I get oil built up on the left valve cover and fairing.  The valve cover gaskets were replaced about the same time as the filler cap housing and for this reason, as I recall.

[Miguel!]

Many riders report using about 1 quart every 3K miles. I do as well. 

Miguel

[Mrclubike]

More than likely you just have a filler cap sealing issue

 

Most people  have had  good successes replacing the upper and lower Oring and you may be better off just trying that again

Their are   more permanent  options  for the filler cap 

I tried replacing the lower Oring but when pressing it in I cut it

I seen The Wunderlich " Dry Safe Oil Filler Plug Kit" but it  is  $110.00 USD 

So this is what I did 

Less than $30.00 USD (Cap kit plus JB slow setting Epoxy)

I JB welded a Billet aluminum Filler cap assembly  from  Amazon  into the opening

The Paint needs to be removed from the opening in the cover Then the Cap base  fits perfectly

I have only ridden it about 400 miles but so far  it is absolutely dry

I have a cast iron engine block that i repaired with JB weld  over 30 years ago and it is still holding strong

I have never heard anything bad about JB weld and I use it a lot

People including me have used it to repair cracked and damaged valve covers with no problems

As always Your Mileage May Very

 

 

 

[Mrclubike]

3 hours ago, Miguel! said:

Many riders report using about 1 quart every 3K miles. I do as well. 

Miguel

 And some even burn more than that

[AndyS]

I would just change the O ring. I can't remember what size it is. I think it is 18 diameter x 4mm cross section. You could change for an 18 x 4.5mm CSA (nitrile or viton would do). This will improve the seal immensely.

[MontanaMark]

I had the same problem on my 99 RT.  Even after changing both o-rings, it would be fine for a while, then begin to leak again.  I found that a tiny bit of road grit was getting into the o-rings.  I started making it a maintenance item to remove and clean these o-rings with every oil change.  After that, no issue.

 

Cheers,

Mark

[Tri750]

With the cost of the custom made leather boots the CHP and our local PD guys mainly use, at the shop I worked at, we replaced the oil filler cap o ring every oil change (6k) and the base o ring every 12k just keep the peace of hearing about oil spots or oil on the expensive boots. 

In a pinch or on the road with a weepy cap, flipping the o ring over is a quick fix.

Experienced owners keep a couple o rings at home or in the tool kit. 

Every 3 k a quart ? Often if you are constantly trying to keep the level full, full, you are chasing your tail. 

The oilheads will seek their own level , some about half way some a bit above or below half. Let it go for awhile and see if the level stabilizes . Constantly adding one glug is a waste of oil. 

[Mrclubike]

On 1/14/2020 at 10:53 AM, MontanaMark said:

   I found that a tiny bit of road grit was getting into the o-rings. 

Cheers,

Mark

 

And possibly  getting into the motor also 

I am glad to be rid of the plastic filler cap

I will definitely let everyone know if I have any issues with the aluminum one