Oil Discussion

This discussion is also likely applicable to most old flat tappet engines, including some VW, Porsche, old Corvettes, etc.

Revised by the Author 11/05/2007, 11/01/2009; minor revision on 06/02/2014; edit again on 06/20/2018

Over the years, oils have been a popular subject for discussions in our motorcycle publications, club magazines, & on-line LISTS & Forums and Facebook, etc. I am not sure just why that is, but I suspect it has to do with our society of easy fixitus, or ‘I need to do something to feel good’, maybe a panacea for the masses…and maybe male ego, ..and who knows what else!  Certainly there is a large amount of placebo effect. REAL facts are hard to come by, and so-called ‘evidence’ abounds, and may be quite difficult to verify. There is a considerable amount of so-called ‘information’. Some is good, some is anecdotal, some based on testimonials, some sort of like ‘my brother told me of his friend who has a friend who told him that…’; or, ‘my mechanic who has decades of experience, says….

Did you ASK that person just HOW he REALLY got that information he is giving you?   Does that mechanic friend have a sweetheart ‘deal’ with a particular oil’s distributor?  Has he ever REALLY seriously tested oils in Airheads?   How did he test them?   Has he looked at hundreds of Airhead cams and lifters?   Do YOU believe the stories often heard>>that “car oils are plenty good enough, you hardly need pricey specialty oils?”.    Some information even seems scientifically derived, and implies itself to be definitive; in MANY instances this is NOT SO. In addition, there is all that advertising. SORRY, but those hyped additives like Slick50, QMI, etc., and those tests on TV of engines run without oil….these are sideshows; you never hear the entire story of the tests.  DO NOT believe these folks. YES, it is true that you MAY (or may NOT) have SLIGHTLY less friction, SLIGHTLY higher fuel economy, etc. HOWEVER, you will also likely get much increased WEAR (YES, you can have LESS friction and considerably MORE wear!), the product may settle out or ‘clump’, thereby plugging oil passages and oil filters, and LOTS more ills. This can lead to oil starvation and catastrophic engine damage. As for additives like Bardahl or Rislone or Marvel Mystery Oil: don’t use them, they can remove the protective coatings on your engine parts.  
BUT:  There ARE A FEW places that Rislone can be of help, and one is temporary use in a Classic K-bike, to hopefully free up a slipping starter drive clutch….aka Sprag Clutch.

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Oil and Filter Changes, Procedures, Technical Information, and the $2000 O-Ring

Your /5 and later BMW Airhead motorcycle has a well-deserved reputation for reliability and exceptionally long life.  Regular oil and filter changes based on both time and mileage are necessary.  Use of a quality oil and quality oil filter is highly recommended.  There have been quite a few different filter numbers, filter styles, and methods of fitting them and associated parts such as O-rings, gaskets, shims, and oil cooler attachments, over the years of Airhead production.  This article will attempt to cover all versions,  models,  situations.  HOWEVER, the Author’s website has several articles, number 49 through 51D, THAT SHOULD BE READ; these cover things in more depth; things you REALLY NEED to know.  Please be sure to read all those articles.

Failure to follow recommended procedures, particularly on /7 and later models, or any model with an oil cooler, can result in $$$ repairs. There is a critical white round large rubber O-ring used on the outer cover on models with oil coolers, and also used on later models without coolers. That O-ring must be in good condition, and under proper mechanical mounting pressure, in the proper way. A failure here can result in an engine rebuild costing at least $2000; and if the crankshaft failed, perhaps over $3500. Reading articles 49-51D on the author’s website AND the entire article you are reading will make you an INFORMED owner, highly unlikely to make an expensive mistake…or allow someone else to make such a mistake.    

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