R1100RT crankcase overpressure?

1289 Views 17 Replies 5 Participants Last post by HappyBoy17, 1 mo ago

HappyBoy17

Discussion Starter · 8 mo ago

This summer I bought my first-ever BMW, an R1100RT 1999 model that's had a pretty soft life. I figure the best first step is to change the dirty oil. Yes I heard the warnings - do not overfill! Sure enough, I overfilled, showing out-of-sight in the glass. Not too bad I thought since I drained out only about a pint or so to get it lower in the glass. Ever since, it has been blowing air+oil past the valve cover gaskets. Did that extra oil mess with the PCV system? I've opened the drain plug at the bottom of the throttle body box and a little oil did come out. Changed out the gaskets and the bolt grommets, no improvement. Anyone got any suggestions?

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HappyBoy17

Discussion Starter · #2 · 8 mo ago

Donald02 said:
Any update yet?

No, this is apparently a problem unique in the history of the world, lucky me. The bike is still in pieces in my garage.

Patric

· #3 · 8 mo ago (Edited)

The way I think the PVC works is a rotary valve in side the motor. It is in timed with the pistons going in and out. I have never heard of one going bad. But, what do I know..

HappyBoy17

Discussion Starter · #4 · 8 mo ago

Is this what we are talking about? This doesn't appear to be internal to the engine and doesn't look like anything I see on my "99 R1100RT.
95 BMW R1100RS R 1100 R1100 RS air breather valve solenoid | eBay

Patric

· #5 · 8 mo ago

Hi , MAX BMW Motorcycles - BMW Parts & Technical Diagrams - R1100RT (259T) . then Engine , then Engine Ventilation .part number 7 . It opens and closes off the vent piping.

Patric

· #6 · 8 mo ago

I can't tell by max bmw on line parts fiche , but I think the part on the link that says air breather is a 13 90 1 341 605 ... maybe ... it is the fuel tank breather valve ...or not..

HappyBoy17

Discussion Starter · #7 · 6 mo ago

Thanks Patric for this useful info. We're tearing into the project soon.

Reactions: 1

micco

· #8 · 6 mo ago (Edited)

Hi!
I was changing motor oil yesterday to R1100RS '98 when I noticed that old oil flows out very slowly. I opened the oil fill cap and oil comes out normally. The breather is completelly blocked. It doesn't breath at all when engine is running.

HappyBoy17

Discussion Starter · #9 · 6 mo ago

micco said:
Hi!
I was changing motor oil yesterday to R1100RS '98 when I noticed that old oil flows out very slowly. I opened the oil fill cap and oil comes out normally. The breather is completelly blocked. It doesn't breath at all when engine is running.

If this is the case, as you suggest it likely is, maybe if I were to rig up a custom fitting to introduce shop air pressure into the case via the oil fill port, I could clear whatever is plugging the passage from the case to the air box? If I keep the pressure under some 20psi, this should do the trick without damaging anything precious in there. Bad idea??
Maybe I'm just lazy but I want to avoid tearing open that engine (that otherwise runs perfectly) unless its absolutely necessary.

HappyBoy17

Discussion Starter · #10 · 6 mo ago

micco said:
Hi!
I was changing motor oil yesterday to R1100RS '98 when I noticed that old oil flows out very slowly. I opened the oil fill cap and oil comes out normally. The breather is completelly blocked. It doesn't breath at all when engine is running.

micco, does your bike behave like mine, soaking your feet in oil as you ride it? With my bike parked at idle speed, I can feel puffs of air with my hand, blowing past the valve cover gasket. At highway speed this air under pressure carries along a lot of crankcase oil.

micco

· #11 · 6 mo ago

HappyBoy17 said:
micco, does your bike behave like mine, soaking your feet in oil as you ride it? With my bike parked at idle speed, I can feel puffs of air with my hand, blowing past the valve cover gasket. At highway speed this air under pressure carries along a lot of crankcase oil.

The owner of the bike burned clutch 6 months ago and it hasn't been ridden since. I replaced the clutch and was doing maintenance when I noticed blocked breather. There are no signs of oil leaks anyway.
I opened the front cover but it was waste of time. Nothing to see there.
I also used compressed air to blow to breather pipe. Nothing goes through.
Then I installed front cover back to engine and blowed some pressure to engine through oil fill port. Nothing comes out from breather.

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Doctor T

· #12 · 6 mo ago

Have you changed the valve cover gasket? An old split one may be your problem

micco

· #13 · 5 mo ago

R1100 engine has two rear main seals and crankcase pressure should flow between them. In this case the outer seal was pushed so deep inside it blocked air passage.

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micco

· #14 · 5 mo ago

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HappyBoy17

Discussion Starter · #15 · 5 mo ago

Doctor T said:
Have you changed the valve cover gasket? An old split one may be your problem

This is the first thing I did. No fix.

HappyBoy17

Discussion Starter · #16 · 1 mo ago

Well I "solved" the problem by putting washers under all 8 of the valve cover bolts, putting additional squeeze on all the rubber gasket seals. This has stopped the horrible air/oil spraying problem. Maybe there should be these spacer/washers installed from the factory but they were discarded or lost by the PO. (?)

beech

· #17 · 1 mo ago

Those bolt rubber washers get old, they are relatively expensive. You need to replace them. Be oh so careful not to exceed the 10Nm torque on the cover bolts.

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RUBBER BUSH

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HappyBoy17

Discussion Starter · #18 · 1 mo ago

beech said:
Those bolt rubber washers get old, they are relatively expensive. You need to replace them. Be oh so careful not to exceed the 10Nm torque on the cover bolts.

11 12 7 654 978
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$5.03

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Beech, I can certainly agree. All 8 of those grommet gaskets are new (yes not cheap) along with the cover seals. Also, one of these bolts was indeed overtightened by the PO, I had to helicoil it. Anyway, now I can enjoy the bike at this perfect time of year.

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