Oil in cylinders

[Shades]

I found what I was missing, taking the front cover off you are able to remove the starter and get to the breather
Will start the bike without the air filter covers and starter cover with the oil in the engine at half full and se if it pumping oil through the breather!
Any thoughts on how the left side is worse than right side is welcome ! The air filter is not fouled with at all, the area under the filter is not flooded...
I know it is a mist when entering the intakes and then becomes liquid when it cools down but still there should be more oil in the filter and breather area right ?

[Kurt in S.A.]

I removed the breather on my /7 without removing the starter. I believe I loosened the mountings in front so that the starter could be tilted up in the back. The issue is getting to the back bolts. I seem to recall using a 1/4" drive with a swivel socket extension. Going back together, if the bolts are reversed so that the nuts are on the opposite end, it makes it easier to remove the next time.

Kurt in S.A.

[Shades]

Good advice Kurt
Will look into it later

[Wobbly]

Yes, this work can be done in-frame. I've completed the same work on both my R100's just as I described. The first step is to simply remove the five 5mm screws and 2 covers and see if you have an issue.

• One cover conceals the oil return "well". It should be empty. If not, then clear the drain hole in the bottom.

• One cover conceals the one-way breather valve. I was lucky enough to have the later model reed valve on both my bikes. It's the earlier model "flapper disc" that has all the issues, so conversion to the reed is the optimal solution if you never want to do this job again.

"Snowbum" has a lot written up on the issue and solutions at: http://bmwmotorcycletech.info/


I found it best to re-install the 2 covers onto the engine with sealant and not the BMW gaskets. This stopped oil weeping and draining out that drilled hole in the engine block near the LH carb.

[Shades]

I found that keeping the oil at half and re-routing the crankcase breather out through the air box and up under the seat with a small filter at the end helped a lot ! Almost did the job. Either the valve guides or oil rings on the left side is bad.
I really think the heads are in good shape, as far as I know they have run less than 5000km since they where converted to led free and the seats and valves looked perfect ! What is the best way to check the guides ?
The engine smokes on start up (I always park it on the center stand) and on hard acceleration.

[Wobbly]

I found that keeping the oil at half and re-routing the crankcase breather out through the air box and up under the seat with a small filter at the end helped a lot ! Almost did the job.

This is good news indeed. But I'm still interested to know what you found when you removed the 2 small covers just to the right of the starter motor. Did you find the "oil return divot" full of oil ? Did your bike have the breather disc, and was the disc chipped or cracked ? Did you convert to the reed breather valve ?

Either the valve guides or oil rings on the left side is bad. I really think the heads are in good shape, as far as I know they have run less than 5000km since they where converted to led free and the seats and valves looked perfect ! What is the best way to check the guides ?

When the valve seats were converted, the guides would most certainly need to pass a mandatory inspection because the mandrel that supports the valve seat cutter is completely supported by the guide. That is to say, the valve seat MUST be cut concentric to the valve guide stem, and the only way to do that is locate the cutter on the valve guide's axial center. Replacing the valve seats is a HIGHLY technical task requiring great experience and expensive tooling. If the guides were loose or out of spec, then the valve seat cutter would not maintain its "center" and the job would need to be aborted. Therefore, I would assume that nothing is wrong with your valve guides.

You keep making this claim that the valve guides are some how "bad" or out of spec, despite oil found in the intake track and defying all logic. Do you know something that you are not telling us ?

The engine smokes on start up (I always park it on the center stand) and on hard acceleration.

1) With the amount of oil puddling in the intake tube that your photos showed, I'd be very surprised if your engine didn't smoke on start up !! It may take several weeks of regular running to remove all the oil from the intake. With your new external breather hose, I'd expect less and less oil smoke on each subsequent ride.

2) My BMW also "smokes" on start up, but this is condensation (water vapor) being released through the exhaust as a normal by-product of combustion with the enriched mixture due to the choke being turned ON. Are you confusing the white smoke of burning engine oil with the white cloud caused by water vapor ??

Hope this helps.

[Shades]

Hi wobbly thank you for your interest!
I forgot to write about what I found when disassembling the starter cover and everything. I found a reed valve, I thought the ‘77 model had the disc type so either I am wrong or somebody changed it. Can the reed valve be oriented wrong ? Read something about that somewhere and mine is “pointing” in another direction than the one in the article.
The oil return was not full of oil so the main source of oil in my intake was the amount of oil in the sump and where the breather was directed. It’s not that I think there is something wrong with the valve guides I just keep debating valve guides over oil rings in my head and hoping it’s the rings. I did check the valves in the guides by hand and everything felt great and the seats look perfect.
I would very much like your opinion on whether to change the compression rings or not when changing the oil rings and if changing the compression rings should I hone the bores? The do not look like new but they do look good and the compression is spot on when compared to the Manuel. So I guess I just do the oil rings right ?

[Kurt in S.A.]

Not sure what you saw regarding orientation of the reed valve, but when I replaced my round board breather valve with the reed valve in my '78 R100/7, I read/was told that the screw holding the reed in place should be placed in the 5 o'clock position or basically pointing to the right foot peg. I think that orientation allows for the air to escape more or less directly into the pathway. I suppose if it has to turn 180 degrees leaving the reed valve, it might allow some of the oil to precipitate out. Might not be that noticeable, though.

Kurt in S.A.

[Wobbly]

...since compression readings are equal and reads 145psi, but the heads have been done a couple of years ago before I got the bike and everything looks good!

► I wouldn't be complaining about 145psi compression !! And we now know the oil is coming down the intake track, so I would NOT be replacing the compression or oil control rings... unless you just happen to have a spare $100 you need to hide from your friendly local tax man.

► You can hone the cylinders if you like for the old rings. If you install new rings you MUST hone.

► Honing should be done with a very fine grit, like 500 or finer. In the USA we have "bead hones" that do a great job. You are simply trying to remove the glaze, not any metal. The hone marks should be at a steep angle so that they form a cross.

The best honing is done in warm water that has lots of dish washing detergent. The detergent will wash out all the abrasive grit left by the hone. Solvents don't clean, they dilute; you need a detergent action to lift out the grit.

► Ring end gaps are checked for minimum clearance, then spaced on the piston 120º apart with no oil.

Hope this helps !