Luftmeister 3-piece oil rings
I used to use them and they WORKED!
I'm putting the old (160,000mi) 100S back together for the short term while I figure the next direction... don't want/need to do its first overbore yet so I want something other than factory one-piece-and-inflexible oil control rings.
Any tips appreciated!
Hmmm...I thought all oil rings are 3 piece, two scrapers and an expander. Is the BMW stock one just pre-assembled or does it look like the compression rings?
I don't know whether the Oilheads and K's use a similar ring but yes the R-bikes use a one-piece oil control ring. It is C-shaped in section as viewed from the end with a scraper at top and bottom.
They work OK I guess on new or newly bored cylinders but my engine always used about a quart of oil per 1000 miles (normal, I was told) and on a hot day after a spirited ride an amazing amount of smoke could erupt from the left muffler when restarted after resting on the sidestand!
When Luftmeister was in business making lots of neat things for our Beemers back then people spoke well of these 3-piecers so I tried them when I did my first valve job at about 90,000 miles. They looked just like any of the Grant oil rings I'd put in my V-8s, and boy did they work! Oil consumption virtually halted, and no more cloud of smoke out the left pipe. I was happy until about 130,000 miles when I decided to re-ring it again and replace the rod bearings and clutch.
I wasn't able to locate more so I replaced new BMW rings which I've been running since. The bike has 160,000 on it now but has been down for a couple of years. I was hoping to make 200,000 before the first overbore and I was thinking that even though it's a BMW I'm sure the bore probably has some taper and the 3-pc rings could handle that better. Oh well, thought I'd throw the question out there!
Concerning the exhaust smoke after being on the sidestand; a recent thread mentioned that if the bike was maintained vertical for 10 seconds after shutdown and then put on the sidestand the smoking should be eliminated. I tried it and it works.
I have a pal who put high compression pistons in his R75/5 many years ago. When he did, he use three-piece rings that he got from an automotive speed shop where he took the piston. Turns out that the same rings fit some model of Harley Davidson. IIRC, there was something floating around a few decades ago about using rings for a Valient or summat. Bottom line is, rings are rings. Take the piston to a GOOD speed shop and they can measure it and sell you some good, three-piece oil rings (for CHEAP).