MOTOBRICK.COM
TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Schnellfahrer on October 13, 2016, 04:54:38 PM
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Greetings,
I discovered this site only a couple of days ago and I think it is marvelous! For several years I owned a 1992 K75RT which was totaled fortunately not with me on it. It was parked and some lady backed into it at a pretty fast clip. Since then I have owned a 1995 K75 with only 22K miles. Now about engine oil.
It is my opinion that 20W50 is great for bikes with wet clutches and in fact that what it is made for. 50 is pretty heavy weight oil and was more designed for the transmission/wet clutch than for an engine with a dry clutch. Yes, I know the gurus at BMW recommend it to be on the safe side with wet and dry clutches.
For a long time I have been using Mobil1 Synthetic 0W40 in both bikes and my 2004 Porsche Boxster. It comes in one and five quart bottles which say: Recommended for European cars, MB, Audi and Porsche. I have discussed this issue w/ an aircraft mechanic friend who rides a Ducati. He is in total agreement with me on this subject.
I'd sure like to hear what you guys (and possibly girls) have to say about it.
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Welcome, Schnellfahrer! How about posting a photo of your bike in the Klassic K-Bike section?
The JASO MA and MB ratings indicate suitability ranges for wet clutches—not that I care. I've got a K75. :giggles I leave frolicking in the oil pools to exotic bike owners, racers, and the tragically obsessed. :hehehe
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BMW recommended 20-50 way before they made any bikes with wet clutches. I can't see them saying in 20 to 30 years we'll be making bikes with wet clutches so let's start recommended it now.
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I run Valvoline or Castrol motorcycle 20w50 or 10w40 during colder temps (starts easier when it's below freezing).
I don't think synthetics are necessary. I know the K doesn't need the wet clutch protection of the oil I use but I figure it's a good, quality oil regardless.
At any rate I bought my Subaru Forester new and used pretty much only Mobil 1. With 197k miles it loves to drink Mobil 1 (couple quarts with 5k oil changes) so I've decided the extra cost isn't worth it, though I use synthetic in my wife's since she has a turbo
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As an Airhead and K-bike rider I follow recommendations from those who have been riding and wrenching for a long time.
Snowbum has not steered me wrong yet and he recommends Mobile 15W50 based on his experience with starter sprag clutch problems.
http://bmwmotorcycletech.info/kstartersprag.htm (http://bmwmotorcycletech.info/kstartersprag.htm)
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FWIW - I use M1 15w-50 in my K100RS, M1 0w-40 in my turbo'd Mini and Saab. Buy in bulk at Costco or with the periodic coupons at AutoZone.
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Winter oil threads are as perennial as the grass.
...Recommended for European cars, MB, Audi and Porsche. I have discussed this issue w/ an aircraft mechanic friend who rides a Ducati.
And this means he knows WHAT about old BMW motorcycles? My dad was a rocket scientist at NASA but he wouldn't know jack about an old BMW. None is so ignorant as an expert, once you get him away from the thing that he is expert about. The best starting point is the factory recommendations. They are made with much thought, a well-equipped laboratory, a knowledge of the machine, and a stake in your success. As the machines age and new materials come along that were not available to the original designers, then the counsel of creditable experts with the particular machine may offer valuable insight. Snowbum was mentioned and others exist as well. What some anonymous poster on the internet with possibly fictitious credentials or experience thinks you should do is an angstrom away from useless.
He is in total agreement with me on this subject.
I'd sure like to hear what you guys (and possibly girls) have to say about it.
Is he in total agreement with you that 20W-50 is designed for bikes with wet clutches? None is so smart as he who agrees with you. Nor any as useless. W.J. Wrigley said once that "when two men in industry always agree, one of them is unnecessary." You have to listen to people who disagree with you to have any chance at learning something. Otherwise, you are simply seeking to validate how smart you are. In my case that answer is usually "not very."
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Greetings,
I discovered this site only a couple of days ago and I think it is marvelous! For several years I owned a 1992 K75RT which was totaled fortunately not with me on it. It was parked and some lady backed into it at a pretty fast clip. Since then I have owned a 1995 K75 with only 22K miles. Now about engine oil.
It is my opinion that 20W50 is great for bikes with wet clutches and in fact that what it is made for. 50 is pretty heavy weight oil and was more designed for the transmission/wet clutch than for an engine with a dry clutch. Yes, I know the gurus at BMW recommend it to be on the safe side with wet and dry clutches.
For a long time I have been using Mobil1 Synthetic 0W40 in both bikes and my 2004 Porsche Boxster. It comes in one and five quart bottles which say: Recommended for European cars, MB, Audi and Porsche. I have discussed this issue w/ an aircraft mechanic friend who rides a Ducati. He is in total agreement with me on this subject.
I'd sure like to hear what you guys (and possibly girls) have to say about it.
Sent from my iPhone using Tapatalk
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Please don't be offended but Your opinion is improperly based. Based on how you've come to this opinion your not qualified technically to make the correct decision on what weight oil you should be using. There is no clutch inside the engine, so why would that play on your opinion? Second there is no gearbox Inside the engine, so shear forces play no part in the engine lubrication requirements.
That being said, BMW designed the tolerances inside the engine between bearing materials and rotating parts. The recommended oil viscosities provided inside your manual reflect their design tolerances based on environmental operating temperatures. The 0W40 does not apply to your bikes tolerances and operation conditions and you will be "under" lubricating your engine if you use that oil. In addition you may notice more oil leaks at seals and joints since the viscosity will be very much thinner than specified. Read the manual and follow the temperature chart. Mobil 1 is fine, just use the proper viscosity/weight recommended by BMW.
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I love oil threads.
C'mon guys don't hold back. :popcorm
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Old K's really don't seem to care what you put in them. Proof is the variety of what owners swear by. Change it and don't run without it. I run cheep name brand 10-40 car oil, bike runs great. Used to use BMW branded 20-50, bike ran great. Only oil related failure I've seen was when the oil filter wasn't seated and the engine lost all oil pressure. I use an AC-Delco PF-53 filter, but that could be another thread.
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Chaos, I hear you. I'm running Shell Rotella T6 5W-40 in my bricks. No problems, including the old 16V RS with 114,000 miles that had sprag issues before I started running the Rotella. It's a heavy duty oil designed for diesel truck engines that routinely run a million miles before rebuilding.
$21/gal. at Walmart. Best price I could find for full synthetic. My K75's don't use any oil at all(1 quart every 4000 miles), but the old RS is using about a quart every 800 miles, so it's nice to have great oil at a good price.
Those AC PF53 oil filters are cost effective which is important when you're doing annual oil changes on three bikes. I can do all three for less than the price of one Hi-Flo.
Regarding oil filters, the worst are Fram. I recall a filter test done by a fluid power engineering society that found that Fram had the worst media and inconsistant manufacturing. They either let everything through or caused so much pressure drop that lubrication was starved. No way I would ever put one in any machine I wanted to keep.
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+1 on the Rotella T6, that my winter oil for the Ural which gets ridden at temps below zero. Synthetic make starting MUCH easier!
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Hello MEDOBSON1. Thanks for your lengthy explanation. FYI it takes a lot more than your friendly dissertation for me to be offended. Common sense tells me that, especially in very cold weather, 0W40 oil starts flowing a lot faster and thus lubricates just about immediately then the syrupy sluggish 20W50. I have used the Synthetic 0W40 for over 12 years and have not noticed any leaks, smoke or other unpleasantness. In fact the few problems I have encountered both on my 1992 K75RT as well as on my 1995 K75 were totally non engine related. Again, I think 20W50 is wonderful for bikes w/ a wet clutch but puts undue and unnecessary strain on a dry clutch K75. However, I respect and welcome different opinions. :bmwsmile
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Oil?
Standard answer is Castrol R, and change after every race.
With a dry clutch I don't guess it matters much, but BMW specifies 20W50 so that's what I use. Mobil V-twin works in everything I have.
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:yow Oil you have to put oil in them, nobody told me, where do you put it? I have 2 gallons of peanut oil will that do?? :dunno
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:yow Oil you have to put oil in them, nobody told me, where do you put it? I have 2 gallons of peanut oil will that do?? :dunno
Might not do much for lubrication, but it will fuel a Diesel engine very well. Petroleum is the "alternate" fuel for Diesel. Rudolf designed his engines to run on peanut oil.
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:2thumbup: Right will start tomorrow on converting the Brick to Diesel, so I can use my 2 gallons of peanut oil. Greatly appreciate the help.
Regards a relieved Martin.
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I used 10-40 for some time but noticed excessive consumption at highway speeds and smoke on startup. I've gone back to 20-50 which has almost no consumption, no smoke and low engine noise.
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Hello MEDOBSON1. Thanks for your lengthy explanation. FYI it takes a lot more than your friendly dissertation for me to be offended. Common sense tells me that, especially in very cold weather, 0W40 oil starts flowing a lot faster and thus lubricates just about immediately then the syrupy sluggish 20W50. I have used the Synthetic 0W40 for over 12 years and have not noticed any leaks, smoke or other unpleasantness. In fact the few problems I have encountered both on my 1992 K75RT as well as on my 1995 K75 were totally non engine related. Again, I think 20W50 is wonderful for bikes w/ a wet clutch but puts undue and unnecessary strain on a dry clutch K75. However, I respect and welcome different opinions. :bmwsmile
The brick engines have been tested to be the coolest running engines in all of MC when they were made. Not because they are dry clutches but because they are designed with a separate transmission with its own gear oil sump, therefor there are no shear forces on the engine oil. That is what is preventing your practice of using a very light weight lubricant from causing problems in the engine. In truth the wear really occurs in that engine when it is first started. This is when most of the wear occurs to the bearings.
If the crank and rods were suspended by needle or ball bearings, the weight of the oil would make Little difference in the wear of the bearings. In the case of the K engines, which employ plain bearings, the engineer designs the size and surface area of the bearings, including the tolerances between the bearing material and the rotating surface materials. When it's all said and done the weight / viscosity is defined and tested on running test mule engines. ( 1980s time frame methods). The other factor is the oil pump and its output pressure using a 0/30 weight oil may not be adequate with an ambient temp above summer days. Basically, the results confirm the bearing wear attributes and a decision is made on what to specify confirming the decision with lube oil engineers being involved based on operating temperatures and bearing temperatures.
I will go out on a limb and believe no 0/30 oil was tested on these engines in the 1980s. I've seen the recommended oil charts before but don't have one handy at work. I do know that 10/40 is on the chart but don't recall if a 5/30 or 5/40 is. I do know that application of 10/40 is very limited to a low temperature range, below 50 degrees. So a 0/30, even if recommended would be limited to deep freeze riding! You are probably not seeing the extra wear your putting on your engine but it's happening, every time you start your bike. I would not use that weight oil in that vintage K bike, your rolling the dice.
Mike Dobson
Machinery Controls Engineer
NAVSEA
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Thanks Mike. It is not quite clear to me why you are now also throwing these other oil weights into the discussion
such as 5W30, 10W40, etc. The only two we're comparing are "your" 20W50 and "my" synthetic 0w40.
I completely agree with you when you say:"In truth the wear really occurs in that engine when it is first started. This is when most of the wear occurs to the bearings". Wise words indeed and I couldn't agree more!
It stands to reason, doesn't it, that it takes a while for the thicker and slower 20W50 to begin fully lubricating in low temperatures especially at start up. No problem there with the initially thinner 0W40 which gets to the bearings without delay with its much lower cold cranking viscosity.
As I have mentioned previously I have used the synthetic 0W40 for over 12 years in two different K75s without noticeable oil consumption, leakage, smoke or engine problems. Lets just say we agree to disagree on this subject, shall we?
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The path of lubrication discourse is always a slippery slope.
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:hehehe
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There is some logic for 0w40 if you are doing really cold temperatures. 5w40 is okay too. I was running 5-40 rotella during the winter when I was riding below freezing. 15w50 is good down to the 40's, iirc the charts they provide.
K bikes have air cooled oil, with fins on the oil pan. This means the oil temperature is somewhat dependent on the ambient temperature and airspeed. So that explains the 40 weight spec at low temperatures, and 50 weight at normal and high ambient.
On the other hand, my subaru has a oil-water cooler, which also serves to heat the oil in winter. It will be held at 190-210 all year, from below zero to hot summer days. So it specs a 30 weight oil, either 5w30 or 10w30 all year. There's no reason to go to a 40 weight in the summer, unless the engine is pretty old so the clearances are larger.
The first number is the cold viscosity: lower is better in regards to startup wear and ease of starting. It has no effect once at operating temperatures, other than that the wide range oil tends to not have the durability of narrower range oil.
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Well there's initial startup and then normal operating temperature to worry about.
What about when it's like near freezing and you're having to do 70+ mph after only a couple minutes or a mile of run time and the temp gauge is still pegged on the low end? Is the multi-viscosity aspect of like the 10w40 I run in colder months taking care of that?
I like how it was pointed out that our oil pans are air cooled and ambient temps likely have a role on operating temperature viscosity. I suppose an oil temp gauge would be the best way of figuring that out.
Isn't there an oil temp gauge that goes in the oil fill for motoboxers?
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Isn't there an oil temp gauge that goes in the oil fill for motoboxers?
there is for boxers, not bricks. Not a straight shot into the sump. Oil temp is pretty well controlled by the engine's liquid cooling. Complete warm up probably takes a good 10 mile jaunt.
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Well there's initial startup and then normal operating temperature to worry about.
What about when it's like near freezing and you're having to do 70+ mph after only a couple minutes or a mile of run time and the temp gauge is still pegged on the low end? Is the multi-viscosity aspect of like the 10w40 I run in colder months taking care of that?
I think that is part of the advantage of 10w40 or 5w40 (yay for cheap rotella t6). Both ends are thinner, accounting for the lower start and operating temps. You could probably pull up a viscosity temp curve online.
With regard to the temp guage being pegged, after a mile or so, it's probably in the low hundreds or so. The gauge is designed to show the operating range roughly.
I like how it was pointed out that our oil pans are air cooled and ambient temps likely have a role on operating temperature viscosity. I suppose an oil temp gauge would be the best way of figuring that out.
Isn't there an oil temp gauge that goes in the oil fill for motoboxers?
There are temp gauges that go in the oil fill on a airheads. Doesn't work on K's though. You could put one in the oil pan pretty easily if you wanted though: just take it off, drill and tap. They probably sell an adapter that puts one in oil drain plug as well.
https://www.amazon.com/Docooler-Digital-Temperature-Celsius-Warning/dp/B00FDMKQOA/
https://www.amazon.com/Equus-9848-Pressure-Electronic-Temperature/dp/B001DKM4PU/ <- Not sure if this is the right size for the K bikes, but same idea
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First let's agree that the oils designation for viscosity is the first number (0,5,10,15 or 20). The second number is the ability or range of the oil to remain the stated viscosity within a standardized design range over a given temperature span. So back to the lower viscosity numbers. Yes if you are operating the K bike engine as discussed in a low temperature range you must reduce the oils "weight" or viscosity. Canadian riders may never use 20W 40 or 50 oils. In winter months it could actually cause an engine failure because the oil would not pump through the system. Same is true for summer hot weather in Arizona a 5 or 0 weight oil would thin out and could fail a bearing, most likely a cam lobe or camshaft plain bearing surface. Now back to the oil viscosity chart in your manual. Note the temperature range of each oil viscosity. This is a generic chart and does not represent synthetic oil properties. It is truly a representative chart based on design standards for a mineral oil based lubricant. Synthetics now have much wider operating bands or ranges than when these bikes were designed. As we all know the primary purpose of engine oil is to provide a lubricating film between moving parts, despite the fact that synthetics perform all the other attributes that engine oils do better than conventional oils the weight of the oil remains a constant property of both types of oils. How the engine was designed and its tolerances is what defines the required weight or viscosity of the oil specified.
In my profession we are constantly evaluating engine lubrication and lubricants for our large Diesel engines that propel small and large warships. Some of these engines were designed before, at and since the Brick engines were designed and built. The more modern an engine typically is, the more restrictive the lubricant requirement is. This seems to be a trend today as fuel efficiency drives designers to reduce frictional losses.
When it comes to gear boxes and synthetics it's a whole different discussion. It's all about shear factors and molecular breakdown.
In the end it's a simple matter of asking BMW NA Technical support about your theory. They have access to the design info to make the call, right or wrong.
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Nice post Medobson1. If I might add a bit to help clarify the viscosity discussion.
On a multi viscosity oil the W number is the basic viscosity. This is the viscosity the oil in the bottle naturally has. By using a lower viscosity base oil you will have more flow and less pressure drop through the system(meaning the last bearings in the circuit will will have more oil) at low temperatures. The problem with a low basic viscosity is that as the engine gets warmer the oil will thin out to where it doesn't lubricate any more.
The second number is the viscosity of the oil at the engine's operating temperature which is defined as 100 degrees C(212 F). The higher this number is, the thicker the oil will be at the operating temperature. Up to a point, the higher the number the better the lubrication. However, if the viscosity is too high, it will be too hard to pump through the engine at operating temperature and downstream bearing will suffer. This second number is achieved by adding viscosity extenders which are additives that prevent thinning as the oil gets hotter.
The problem with viscosity extenders is that as they "cook" out of the oil the oil gets thinner, and lubricates less. This is one of the processes that causes the oil in your engine to "wear out". Modern oils have better extenders that last longer so service life is longer and you can go more miles between changes.
The result is that when you look at the W number you have a choice; less lubrication at low temperature vs. shorter service life. The wider the gap between the two numbers the more extenders have been added and the faster the oil will "wear out".
The hard part is finding out how fast the extenders breakdown. By buying a major brand and changing at reasonable intervals I would think that we will be changing before the oil stops protecting the engine. That is why I use Rotella T6. It is a heavy duty oil designed for heavy duty diesels that owners want to run as reliably as possible for up to a million miles or more in a wide range of operating conditions.
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:popcorm
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This thread is what happens when not enough people have friends with Ducatis. :musicboohoo:
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Ok I have no friends with Ducati's (though at least one acquaintance, does that count?) so I have a question. I live in Costa Rica where a really cold evening is 60 fahrenheit and the average day is around 80f and a hot day is close to 100f. Does this mean that all this very scientific thread is irrelevant to me and I should just use whatever happens to be available or does it still matter? I ask because I have to change the oil tomorrow and was thinking to getting 10 W 40 like I run in my car (a 2012 VW Passat)
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Take your lowest expected temperature Fahrenheit and divide by 3, and divide your highest expected temperature by 2. This will give you a mathematically derived suggested oil viscosity. Adjust to whatever you wanted to use anyway. I just made this up so it must be true.
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Take your lowest expected temperature Fahrenheit and divide by 3, and divide your highest expected temperature by 2. This will give you a mathematically derived suggested oil viscosity. Adjust to whatever you wanted to use anyway. I just made this up so it must be true.
Having just seen it on the interwebs I know it is true.
I don't have any friends, let alone friends with Ducati's. Still trying to decide if I even want any.
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I live in Costa Rica where a really cold evening is 60 fahrenheit and the average day is around 80f and a hot day is close to 100f.
20w50
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I use Mobil 1, 15-50 and buy it in a 5 qt jug from Wally World for $22.88. I fill to 3.5 quarts.
I switched from Valvoline M/C 20-50 dino oil because I had experienced "blow by" upon hard deceleration (bad smell) while using it.
Since switching to the Mobil 1, I haven't smelled it at all. :cowpoop:
BTW, (doing my best Ed McMann) ..... WHEEEEEEEEEEERRRRE'S JOHNNY?
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old thread, I know... but pertinent data to follow up on Medobson1's info
First, oils have to fall within a range to be labeled a certain weight, so actual viscosities can vary quite a bit between manufacturers.
40W viscosity range at 100c: 12.5 to 16.3 cSt
50W viscosity range at 100c: 16.3 to 21.89 cSt
And some examples:
Type, Viscosity 40c (cSt), Viscosity 100c (cSt)
Mobil 20w50, 185, 20.5
Mobil 15w50, 125, 18.0
Mobil 20w40, 118, 14.2
Mobil 10w40, 89.3, 13.3
Mobil 5w40, 80.0, 13.7
Mobil 0w40, 78.3, 13.8
So we see that the hot viscosity varies a bit depending on the basic (cold) weight, with a higher basic weight typically having a slightly higher hot viscosity. Otherwise, a 0w40 is pretty much the same as a 20w40 at running temperatures where it matters, until the oil degrades. Mobil still claims 10,000 mile service intervals, but that seems a bit far fetched; I'd like to see viscosity data at 1000mile intervals up to 10k miles, but I don't see anything like that online right off.
Anyways, Its getting into the colder months in Colorado (30f overnight at 60f highs), so i'm switching from 15w50 to 0w40 for a few months.