That's why I asked after the very first post.
I work in a field where I have to do a lot with oil, hydraulics and related issues. The main outside effect that makes oil lose its lubrication properties is contamination, NOT heat cycles or just time in operation. There are systems in vehicles where experts recommend NOT to change oil if possible at all, because the process of changing will introduce problems into the originally clean circuit. Hydraulic power steering systems, for example.
Now, if you are selling oil, you clearly have a conflict of interest when you enter into a discussion about frequency of change intervals.
I am not going to comment on the frequency of changes. Lots of folks have. As for MMO, why a detergent is needed with such frequent changes evades me.
Finally, and most importantly - gear oil. The basic spec for both the transmission and final drive is 90wt GL5 rated gear oil.
For transmissions only: 80w90 and 75w140 are specified as acceptable.
For final drives: 80w90 is specified as acceptable.
I have found these specifications in the factory manuals for at least 20 different year/model Oilheads and K bikes and have found no other believable specifications for such bikes. One CD, for one year K1200LT differed but was changed backt the following year.
I find it ironic than a person who is using an out-of-spec lubricant in the final drive had a ball bearing failure at 39,000 miles. A review of technical literature regarding ball bearings makes it pretty clear that oil viscosity, operating temperature, bearing clearances, and loading are critical to proper bearing function and to bearing life. Oil that is either too thin or too thick is detrimental.
Specifically, oil that is too thick may, under certain conditions, "wedge" out in front of the rolling balls. This leads to inadequate oil between the balls and the races. This allows the balls and races to go "metal to metal" which is not supposed to happen. This causes fractures and pitting in the hard races and sure impending death for the bearing. This by the way is the failure mode for the vast majority of reported final drive failures.
For all final drives prior to the introduction of the "big hole" drives on the K bikes and R1200, if anybody including a dealer puts 75w140 in a final drive they are not in accordance with the specifications no matter what they say, or how earnestly they say it. And in my carefully considered opinion it does matter and is detrimental to the final drive.
While there are undoubtedly several factors involved in the many final drive failures, improper lubricant is clearly one of them. Others include shimmed to tight (inadequate bearing clearances for the oil), shimmed too loose (pounding), impact loads from sharp bumps (GS bikes anyone?), and excess loading (two-up K1200LT with full camping/touring gear). I would note that proper gear oil providing optimal cushioning can mitigate some, but not all, of the hazards imposed by the other factors.
Paul Glaves - "Big Bend", Texas U.S.A
"The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
Regardless of "years of experience" guys like you can't hold a candle to someone with a viable engineering degree and experience in design and production of BMW motorcycles. Similarly qualified guys from other makes may have valid comments as well, but the mechanic's one and only job ever is to restore the bike to factory condition via repair and maintenance. Unless you're quoting factory information, your statements are of little (very little) value. And I don't mean Amsoil hype I mean information from BMW. It's good, BTW, to actually understand the difference between "recommend" and "specify" and BMW does both and they shouldn't be confused.
To promote the notion that BMW maintenance specifications come from lawyers, salespersons, etc., is the height of ignorance and represents nothing more than scare tactics and snake oil promotion.
And, it's not a matter of "believes," it's a matter of knowing through observation how the flow of information works, beginning with design engineers, the field experience process, the service personnel training process, all the way to service information communication to dealers and customers. It's not a perfect system, but continuous assessment and improvement is part of it, and everything else is such a distant second as to be minuscule ... despite the testosterone that might be applied.
'12 R1200RT, '02 R1100S, '84 R80G/S
OK so you bought the bike at 36,200 miles and the final drive went at 37,000 miles. This will be hard for you to believe obviously given your convictions however it probably had nothing to do with the oil and everything to do with incorrect bearing shimming or severely abusive loading or riding. That black puddle you found is from the seal deteriorating after the bearing goes and melts it and very likely not from the oil itself. This is pretty well documented elsewhere. If you had owned the bike since new you would have changed your final drive oil over 14 times at that point. Guess what? It probably would have failed anyway.
It is also dead obvious that despite what you may think you are over doing the service intervals with products not intended for use in your bike by the people who designed it. The forums are great places to learn but a terrible place to preach as I'm sure you've noticed. You should at a minimum consider the advice of those with just as many (or more) years of experience as yourself. Riding and wrenching on cars and bikes for 40 years is nothing special around here, trust me. I have to wonder how much of that experience was just changing fluids?
Even though the best advice here agrees with you that changing the final drive oil more often than recommended is a good idea you are so far beyond that it makes no sense. More really isn't always better. Having cheap access to Amsoil products is no reason to over use them. Maybe save a few quarts for the kids eh?
From the factory manual for YOUR bike:
00 11 229 Changing the oil in the rear wheel drive
(Inspections I, III and IV)
every 40,000 km (24,000 miles) or at the latest every 2 years
? Change the gear oil at operating temperature.
to bottom of thread in oil filler hole
...... approx. 0.25 l (0.44 Imp. pints/0.26 US quarts)
Oil grade for rear wheel drive:
Brand name hypoid-gear lubricant SAE 90 API GL 5
MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
'81 R80G/S, '82 R100RS, '00 R1100RT
Just think about that the vehicles we buy - in this case motorcycles - aren't just produced according to a drawing in an office. Once they reach a prototype or pre-production status they go through extensive field tests on the road and the components are submitted to rigorous lab tests that are designed to simulate years of use in order to verify designs and determine durability.
Just think about how long before you see a bike that you can buy on the showroom floor have you seen pictures of disguised models on the internet caught during test rides.
Forgot to mention that I also clean my KN air filter and re-oil every 2,000 miles whether it needs it or not. I also vacuum out any debris from the air box.
I've also added N48 Neodymium magnets to the bottom of my oil filer, oil drain plug, transmission drain plug and FD drain plug. You'd be surprised how much crap they collect. Highly recommend doing this to a new bike and especially to an older bike you just purchased since in most cases, you have no good means of determining how well the bike was maintained (unless of course the last owner keeps meticulous records and receipts like I do).
Lets burn some gas, use more oil, leave rubber on the road and increase our carbon footprint today! That should piss off NObama, Boxer and Feinstein really well.
Sent from my iPhone
Finally, this thread is worth being send to the "Crapper"
From "worthwhile", then "reasonable", then "credible", followed by a notable downgrade to "possibly believable", on to "valueless", then to "foolish", right onto "pointedly ignorant", and culminating in "just another useless internet troll" in 22 posts.
Ride Safe, Ride Lots