Black smoke is a carb "rich" mixture condition. White smoke is typically oil consumption.

There are many reasons you might be burning excess oil other than rings. If this was a hot running British vertical twin, then rings would be the prime suspect. But the BMW runs so cool that rings are actually the last thing on the list. Some ideas....

• Dirty air filters increase oil consumption because it forces air in from the engine breather. Replace the air filter and make sure there are no birds nests in the air intake.

• Remove the small cover(s) to the right of the starter motor that make up the breather system. a) There is a "well" with a tiny drain hole. If that small hole is blocked, then oil pools up and more oil leaves the breather than normal. b) Make sure the one-way breather disc is not chipped or cracked. Replacement with the later "leaf spring" type off an R100 is always good. c) Forget gaskets; seal both covers back in place with 'Hondabond' or one of those semi-permanent sealants to stop all oil seepage from the top of the engine. d) While you're there, oiling the 3 bushings of the starter motor is always a good thing too.

• Your engine oil should be a 20W50 API rated SF/SG, and not a synthetic. Suggest Valvoline 20W50 VR-1 "racing oil".

• Some smoking on start-up or at traffic stops is not a concern. Steady signs of oil burning going down the road with lowering of engine oil level is. You can install new rings at the next push rod seal replacement.

• Minor loss of engine oil level can be easily offset by fitting the deeper sump plate off an R100. These are very easy to find and cheap to purchase used, and a much easier job for a home mechanic than new piston rings.

Hope this helps.

Wobbly, you are the man. I can't tell you how much we appreciate you looking in on us newbees. I've done all my work myself with excellent into from the veterans such as you. I will check back in as I go thru your check list. The simplicity makes this machine a dream to own and explore. Best to you and yours. Ride safe. CTC

Wobbly, when you say a sump plate, do you mean the entire deeper oil pan or are you saying the later models have a larger or deeper oil pick up with the strainer? I didn't know if the pick ups were different sizes after mine. Thanks again, CTC

► Think of it this way.... R60/R75 was the starting point. As the engines got bigger (R90, then R100), the finned oil pan on the bottom of the engine got deeper and deeper to hold more and more oil. A deeper oil pan means the oil doesn't circulate as often, AND the pan protrudes further into the air stream. So the oil runs cooler. Secondly, if your dipstick is reading down 1/8", with a deep oil pan that represents a much smaller percentage of oil loss. The results are 1) slightly longer warm-ups for 2) more peace of mind.

► When the pan is deeper, the oil pickup also has to be deeper. BMW does this by placing a simple aluminum spacer between the pickup strainer and the pump. Held in place by 2 slightly longer bolts. So it's the same pump and strainer, the strainer is simply mounted in a lower position.

Click here and look at this Mac ad. You can clearly see the spacer and longer bolts for this 4qt pan.

Hope this helps.

Cliff

When filling the crank case with oil, the level should be about half way between the top and bottom lines on the dipstick with it not screwed in and sitting on top of the opening. The bike should be on the center stand and somewhere near level. The airheads I've owned would blow out the extra oil until it was happy with the level.

Bob

Cliff

When filling the crank case with oil, the level should be about half way between the top and bottom lines on the dipstick with it not screwed in and sitting on top of the opening. The bike should be on the center stand and somewhere near level. The airheads I've owned would blow out the extra oil until it was happy with the level.

Bob

Wobbly, may I ask one more question for clarity? When you speak of the reed vs the disk version, did you mean on the "non return valve", or are you referring to...... BMW R80 R90 R75 R60 R100 airhead motor breather valve ...... that item is listed on ebay right now. I was a bit confused. I haven't opened up my machine for this project yet, because it is running well and the tank removal is a drag, just painted it. I will once I understand the project clearly before I go in. Thanks again, your really helpful to us with desire and some skill...................

The "breather valve" as it's called on Ebay is what I was discussing. The round fiberglass disc with the hole in the center (shown in several of the current auctions) gets pushed open as the crankcase expels crankcase gases, then closes shut. Those discs are made of thin sheet, and they can get chipped or nicked. When that happens, the engines apparently loose a lot more oil. In the late 70's, BMW replaced those fiberglass discs with a metal reed that never has issues.

Photo of the disk type breather valve

I am certainly no expert, but from what I read the disc system works very good, but may need a new disc every decade or so. Or, if you feel industrious you can replace the whole assembly with the later model reed system.

Does that clear things up ?

I bought the '70 style BMW breather for a R75/5. I have a question if you can answer it, I opened the bike and my '72 has the spring loaded plastic ring covering the three holes. Do I have to pull that entire unit out in order to place this reed style breather in that hole using the same breather cover and air intake tube. If you have any input on that I would really appreciate it. Best to you, Cliff

I went in to replace mine, but discovered the later type was already installed. So at this point I have to admit that what I'm telling you is all based on research reading (mainly Snowbum), and not experience.... but the consensus was that you pop out the old unit complete, warm the case, and insert the whole new unit. What I can't tell you about is the unit's "fit" which will determine the level of trouble you'll encounter to replace said unit. I have no idea if the new unit is a 1/4 oz "slip fit", a 1 lb "push fit", or a 200F degree engine case and frozen valve body "shrink fit". So, the decision to replace is based on your array of tool options (heat gun, propane torch, Harley hammer) and your creativity as a mechanic.

However, there is nothing wrong with the design or operation of the older disc type, except that the fiberglass disc needs renewing every so often. What gets me is why they simply don't make an metal disc replacement part.

Thanks, as always I will report back. I may be in for some rings after all of these first line efforts are completed. Appreciate all.......CTC

I may be in for some rings after all of these first line efforts are completed.

You'll want to do rings and push rod tube seals together at the same time. Ring replacement will call for specialized cylinder honing, if you don't have Nikasil cylinders.

Do not under any circumstance order your rings from Capitol. Those clowns sent me mis-matched rings from 2 different manufacturers. :angry: It's not worth the $4 you save over matched BMW parts from Max.

Thank you so much Wobbly. Hope our paths cross at some point. I am a NYC kinda guy. Live by Kennedy but work in NYC daily. Best to you. CTC

Hope we do meet some day.

BTW the VW bus you have in your icon. I saw where one sold on Ebay for something over $60K !!! Didn't study the details, but being a child of the 60's, I remember when everyone had one.