Do I need a new cylinder head cover?

[nateschisler]

2009 R1200RT - I have a small, but persistent leak coming from/through the "donut" gasket that seals around the sparkplug boot.  If I pop the plastic cover off, I can see oil in there.  I assumed it was a bad gasket so replaced both the "donut" gasket and the outer gasket, reinstalled cover, torqued to 10 n/m, still leaking. 

 

Are there any easy tests I can do to confirm the cover is warped and/or needs replaced?  Any other secrets/hacks out there?  Seems to me that for some reason the gasket isn't making sufficient contact with the surface on the cylinder side and oil is getting pushed out - but I'm just guessing.

[dirtrider]

11 hours ago, nateschisler said:

2009 R1200RT - I have a small, but persistent leak coming from/through the "donut" gasket that seals around the sparkplug boot.  If I pop the plastic cover off, I can see oil in there.  I assumed it was a bad gasket so replaced both the "donut" gasket and the outer gasket, reinstalled cover, torqued to 10 n/m, still leaking. 

 

Are there any easy tests I can do to confirm the cover is warped and/or needs replaced?  Any other secrets/hacks out there?  Seems to me that for some reason the gasket isn't making sufficient contact with the surface on the cylinder side and oil is getting pushed out - but I'm just guessing.

Morning nateschisler

 

It will be difficult to tell much about cover warpage without a good straight edge or better yet set the cover up on a granite block & use a precision height gauge. Even then you will need to measure a known good cover for comparison as there are no BMW published cover checking specs.

 

Are you SURE that the donut is leaking????

 

There is a lot of forgiveness in the gasket & donut so the cover would have to be pretty distorted to leak at the donut   area.

 

Has the motorcycle ever been  been dropped on that side cover?? If not then your leak is probably caused by something else. 

 

Are you sure that the spark plug isn't leaking (the spark plugs will sometime leak at the base gasket or even leak at the porcelain to base crimp). The leak looks like oil but is more of a gooey looking substances. 

 

There is also a casting passage from the front of the cylinder head (next to the exhaust pipe connection) that leads back into that donut area. Water, or leaking oil,  can enter the external donut area from the front so verify that isn't happening.

 

Has any of the 4 cover attaching stud boss threads in the cylinder head ever been stripped out? If so then make sure that the thread repair didn't leave one or more of the thread inserts sticking proud of the boss top. Any part of a thread insert sticking above the top of the cyl head boss could prevent the cover from properly pulling all the way down tight  to the donut.

 

 

[nateschisler]

Hey dirtrider,

 

As always, thanks for the thorough response.  It is for sure engine oil and for sure originating in the donut gasket area.  I say that because of the following:

 

- after any ride of more than say 15 mins, if I pop the plastic wire cover off there is engine oil present in that donut recess area

- after a ride of more than 30 mins, it makes its way out and streaks down the cylinder head, then will leave a little drop spot where I park the bike

- if I cleanup the recess, it returns next ride

- there is no water or mystery goo or contaminants of any kind, it is dark honey colored engine oil

 

The mounting bolts have not been stripped and/or repaired.

 

There is a healthy scuff mark on the bottom of the cover which I assume to be from a low-ish speed drop.  I intentionally didn't mention that up front as I assumed somebody would key-in on that point alone.  I've owned the bike for 3 months and the leaking started 2 weeks ago - and I haven't dropped it.

[dirtrider]

18 minutes ago, nateschisler said:

Hey dirtrider,

 

As always, thanks for the thorough response.  It is for sure engine oil and for sure originating in the donut gasket area.  I say that because of the following:

 

- after any ride of more than say 15 mins, if I pop the plastic wire cover off there is engine oil present in that donut recess area

- after a ride of more than 30 mins, it makes its way out and streaks down the cylinder head, then will leave a little drop spot where I park the bike

- if I cleanup the recess, it returns next ride

- there is no water or mystery goo or contaminants of any kind, it is dark honey colored engine oil

 

The mounting bolts have not been stripped and/or repaired.

 

There is a healthy scuff mark on the bottom of the cover which I assume to be from a low-ish speed drop.  I intentionally didn't mention that up front as I assumed somebody would key-in on that point alone.  I've owned the bike for 3 months and the leaking started 2 weeks ago - and I haven't dropped it.

Morning nateschisler

 

OK, then it does sound like  something isn't right with that donut sealing area. The usual cause is the lip on the donut getting folded over. You probably need to remove the cover & look for cracking on the cover in the spark plug surround area of the cover. 

 

Make sure that the donut goes on the cover  correctly & "stays on" as you install the cover.

You might also try instilling the donut on the cover with a thick bead of high temp silicone sealer (don't push the donut on to tightly), then allow to sit overnight THEN install & torque the cover on (this will force a tighter donut to cyl head sealing).

 

[lkraus]

I'm assuming the mounting bolts are also not bent, moving the cover off center. You would notice that as they would wobble while turning. You might be able to detect any warping of the cover by placing a very thin, even coat of grease on the edges and lightly pressing it to a window or other flat piece of glass.  It's time for spring window cleaning anyway.

 

If the scuff mark does not bother you, I'd be inclined to try a little silicone gasket sealer on the donut rather than replace the cover.

[nateschisler]

I was thinking about the hi-temp silicone solution and now that 2 experienced members have suggested it, that's good enough for me.  I wasn't sure if that level of mechanical hackery constituted full Bemmer Blasphemy or not

 

I'll also try the greasy window thing as inquiring minds (mine) want to know, and the mounting bolts are not warped.  My suspicion is the scuff from the low speed impact has caused the cover to warp to a slightly more convex shape allowing oil to sneak past the seal.  

[dirtrider]

2 minutes ago, nateschisler said:

I was thinking about the hi-temp silicone solution and now that 2 experienced members have suggested it, that's good enough for me.  I wasn't sure if that level of mechanical hackery constituted full Bemmer Blasphemy or not

 

I'll also try the greasy window thing as inquiring minds (mine) want to know, and the mounting bolts are not warped.  My suspicion is the scuff from the low speed impact has caused the cover to warp to a slightly more convex shape allowing oil to sneak past the seal.  

Morning nateschisler

 

You want to use that silicone sealer to apply more clamping force to the donut so only use silicone on the cover side not on the cylinder head side. Then allow the silicone to set up in it's thicker configuration before bolting the cover on. (you want the silicon to increase the donut thickness slightly) 

 

Do thoroughly inspect for cracks at the cover donut area as you said it didn't leak then it suddenly started so something has changed. 

[nateschisler]

Dually noted, will give 'er a go!

[The Fabricator]

Maybe widen the scope of your investigation.  

Examine the cover for cracks.  I recently bought a used cover for an 1150.  It was a right that was installed on the left head.  It cracked the cover.  Not suggesting that is the case here.

Maybe the crash cracked the cover.