Older K-bike oil change interval

[OfficerImpersonator]

I searched the old threads and never found exactly what I'm looking for, so I thought I'd ask it here...

I have a 16 year old K75S. In the fall of 2004, the previous owner had the local dealer do a "Level II" service on the bike. She went 200 miles in the next two years.

I've put 3300 miles on her in the past six months I've owned her. When I first got her, I replaced the oil. Since then, I've replaced all the other fluids in addition to a bunch of other things.

I'm getting fairly confident working on the bike, and I'd like to earn some pride and save some money by changing the oil myself. I have both the Clymer's and Haynes manuals and it looks rather straightforward.

1. When should I next change the oil? 300 miles ago? At a 6,000 mile interval as some suggest? Some other interval?

2. I think I recall seeing somewhere online an "oil change kit", that included a new filter, new seals, and maybe even the proprietary BMW oil filter wrench. Does anyone here know what I think I'm remembering? Anyone have a source they recommend for the kit?

3. As bikes age over time, should we shorten the frequency between fluid changes?

[roy]

I believe beemerboneyard has the kits and also the oil filter wrench.

www.beemerboneyard.com

Oil change interval depends on some variables:

Do you do a lot of in traffic stop-n-go riding or do a lot of short trips? I.e. 10 miles or less. I would change oil more frequently under these conditions.

or do you ride 500 + miles tank to tank.

It is your bike and you will get a lot of different answers.

My perspective is that "Oil is Cheaper than Parts".

How often do you change oil in your cages? Might use this as a reference also.

Roy

[SheRidesABeemer]

When you buy the filter "kit" at the dealer you get a new seal. You'll want to pick up a wrench. I use the same filter and wrench for both my K bikes. I change my oil every 4,000 just because I don't want to be under the bike every month.

[jdiaz]

I change every 3000 or so.....try to make three changes every 10K miles when I do a major service. I have a collection of six rubber o-rings that I rotate thru, and purchase individual filters (not the kit). I usually buy the crush washers in bulk since the same sizes are used on all of our bikes. And don't spend a lot of money on oil for your K75. They don't need anything exotic . But that's a whole 'nother religious discussion. :laugh

[RandallIsland]

The last time changing oil, I was wearing a sleeve up white button-down, and the total time with a hot (not warm) bike that had been doing 90 ten minutes before, took exactly 25 minutes including cleanup.

Do it often, do it right and do it again.
Totally ...

[ptero]

I've put 3300 miles on her in the past six months I've owned her. When I first got her, I replaced the oil. Since then, I've replaced all the other fluids in addition to a bunch of other things.


My inclination would be to change the oil NOW, regardless of what interval you will settle on for continued ownership.

The first oil change (which you already did) would not have completely cleaned it out from the storage. The oil you put in has likely picked more remnants from the storage. So, I would not think it to be cleared until one more change.

I usually change it every 3k anyway. But sometimes that stretches as far as 6k.

[deilenberger]

People like to pull numbers out of the air on when to change oil. I like to base my changes on data - so I've had my engine oil analyzed.

On a K75 - if you run Mobil1 15W-50 (good range for the engine) Extended Use - you can easily go one full year or 10,000 miles between changes - whichever comes first. I tended to usually ride around 8,000 miles a year - so it got an annual oil change. Since I also rode the bike year round - there was no need for a spring change to flush any stale oil - it never got "stale". Looking at the inside of my valve covers - there is no evidence the oil was not keeping whatever particulate matter the filter didn't capture in suspension - ie - there is no sign of sludge.

A good source for oil analysis is Blackstone Labs - they are quite familiar with the K75 engine and know what to look for that would indicate wear or exhausted oil. They will send you a free capture kit for the oil that you use to send it to them for analysis. See: http://www.blackstone-labs.com/

YMMV - and it usually will, but I still prefer DATA.

[Mudbug]

The BMW recommended maintenance interval for my 1991 K100RS is 5000 miles. The BMW recommended maintenance interval for my 04 K1200GT is 6000 miles.

Does this waste oil? Probably.

I like what deilenberger posted. My only concern is water and gas in the oil.

[OfficerImpersonator]

People like to pull numbers out of the air on when to change oil. I like to base my changes on data - so I've had my engine oil analyzed.

On a K75 - if you run Mobil1 15W-50 (good range for the engine) Extended Use - you can easily go one full year or 10,000 miles between changes - whichever comes first. I tended to usually ride around 8,000 miles a year - so it got an annual oil change. Since I also rode the bike year round - there was no need for a spring change to flush any stale oil - it never got "stale". Looking at the inside of my valve covers - there is no evidence the oil was not keeping whatever particulate matter the filter didn't capture in suspension - ie - there is no sign of sludge.

A good source for oil analysis is Blackstone Labs - they are quite familiar with the K75 engine and know what to look for that would indicate wear or exhausted oil. They will send you a free capture kit for the oil that you use to send it to them for analysis. See: http://www.blackstone-labs.com/

YMMV - and it usually will, but I still prefer DATA.

I ride around 10K a year, so once a year sounds good to me!

Is there anything can can be discerned from observing the color of the engine oil, as viewed through the sight glass?

Obviously as the oil gets cooked over and over again in the engine, and as it picks up bits of impurities and dirt over time, it will change color.

Can this color change be used to discern the condition of the engine oil, or does this color change take place so early in the life of the particular batch of oil as to be essentially useless in determining the oil's condition?

In the 3,000 + miles since my oil was last changed, the color of the oil has gradually darkened over time. All things being equal, does this "darkening" of the oil's color indicate it might need to be changed sooner than 10,000 miles, or might a "darkened" oil still have ~7,000 miles of life left in it? Is the color of the oil usually irrelevant?

Obviously, if I see a layer of water sitting on top of the oil in the sight glass, I have a problem. Obviously, if the oil turns cloudy or murky or turns into the color of molasses, I have a problem. But as it becomes less "yellow" and more "amber" over time, can we use this change to predict the oil's useful life - or am I attempting to read tea leaves here?

[deilenberger]

The BMW recommended maintenance interval for my 1991 K100RS is 5000 miles. The BMW recommended maintenance interval for my 04 K1200GT is 6000 miles.

Does this waste oil? Probably.

I like what deilenberger posted. My only concern is water and gas in the oil.Which is why I posted the link to Blackstone's website. Get your oil tested - the basic test is only $25 - less than the cost of one unnessary oil change.

Then make up your own mind. If the engine isn't broken - the oil will not have any problems with gas or water in it.

[deilenberger]

I ride around 10K a year, so once a year sounds good to me!

Is there anything can can be discerned from observing the color of the engine oil, as viewed through the sight glass?
Yes - if you're low on oil. That's about it..

Obviously as the oil gets cooked over and over again in the engine, and as it picks up bits of impurities and dirt over time, it will change color.

Can this color change be used to discern the condition of the engine oil, or does this color change take place so early in the life of the particular batch of oil as to be essentially useless in determining the oil's condition?
I'd suggest having your oil tested - that should answer the question for you. Do it at your normal change interval.. see what the results are and then decide how much further you're going to try using it.
In the 3,000 + miles since my oil was last changed, the color of the oil has gradually darkened over time. All things being equal, does this "darkening" of the oil's color indicate it might need to be changed sooner than 10,000 miles, or might a "darkened" oil still have ~7,000 miles of life left in it? Is the color of the oil usually irrelevant?
The darkening of the oil is some combusion byproducts (carbon mostly) in suspension - particles too small to be captured by the oil filter. The oil is doing exactly what it's supposed to do when it turns darker - it's keeping the particles in suspension and not forming sludge.
Obviously, if I see a layer of water sitting on top of the oil in the sight glass, I have a problem. Obviously, if the oil turns cloudy or murky or turns into the color of molasses, I have a problem. But as it becomes less "yellow" and more "amber" over time, can we use this change to predict the oil's useful life - or am I attempting to read tea leaves here?

I'd suggest - again- gathering some data on your own bike. Do a "normal" interval oil change and send a sample of the oil off to be analyzed. It could be you DO have a hidden engine problem the analysis will turn up, but chances are the analysis will show you that all the oil parameters are well within spec, and it could be used longer.

On "classic" K bikes (not the new 1200's with an upright engine) - you have what is basically an automotive engine design, without shared clutch/transmission oil. The requirements for oil in this engine are the SAME as in a car engine. The change intervals should be the same as in a car engine. It doesn't need magic oil, and indeed - some motorcycle specific oils have less extreme pressure additives in them to prevent causing clutch slip in engines that have the clutch in the engine oil - these oils wouldn't be as good for a K engine as standard automotive oil would be. I prefer synthetics because of the extended change intervals, and resistance to viscosity breakdown with temperture.. but they aren't absolutely needed if you're willing to change a bit more frequently than I do.

An oil test of what you're doing now will tell the story.. and then you can post it back here and let us know the results.

[OfficerImpersonator]

The requirements for oil in this engine are the SAME as in a car engine. The change intervals should be the same as in a car engine.

So the higher compression in a motorcycle engine doesn't impart higher stresses to the engine oil than it does in the typical automotive engine?

[deilenberger]

So the higher compression in a motorcycle engine doesn't impart higher stresses to the engine oil than it does in the typical automotive engine?What higher compression?

The K bike engines last time I looked were in the region of 9:1 or 10:1. Modern car engines (like the BMW M series engines) frequently run over 11:1 and up to 12:1.

So the short answer is: no.

[Kayseventyfive]

Obviously, if I see a layer of water sitting on top of the oil in the sight glass, I have a problem.


If you see water floating on oil, we ALL have a problem, as gravity has been reversed and we will fall upward into outer space.

.

But seriously, water will be on the bottom, where you can't see it. Short rides can cause water to form, so ride it, ride it, ride it. A friend who is a petroleum engineer says 20 miles for a car engine is minimum drive for best engine life. A retired engineer for Wright Aeronautical engines told us that cold starts were the absolute worse things for a gasoline engine. Part of that was the water, pollution and acids that formed in the oil.

When I worked, my commuter bike was always some cheap 2-stroke so there were no cold start, short drive oil issues. I just couldn't stand to hurt a good bike that way.

[brahma]

I've had the same '85 K100RT for 20 years. I have changed the oil religiously at 2000 mile intervals. I have a BMW inspection sheet from those years ago that states clearly 1800 mile intervals.

[deilenberger]

I've had the same '85 K100RT for 20 years. I have changed the oil religiously at 2000 mile intervals. I have a BMW inspection sheet from those years ago that states clearly 1800 mile intervals.Trying not to be rude - but - you've truely wasted a huge amount of oil.

A lab test would have shown you that the 2,000 mile oil you were taking out was still just as good as new - even if it was $1.99 K-mart special. I owned an '85 K100RT - saw it last night at our local club meeting. It's narrowing in on 100k miles now, and it received very regular 5,000 mile oil changes with Castrol GTX. If I had been using synthetic at the time - I would have felt safe extending it to 8,000 miles or yearly - whichever came first - based on actual tests I had run on oil run in a K bike.

YMMV - but in this case - I don't think so..

[RandallIsland]

Thanks Don.

I just never knew that. It reminds me of a quote.

Oil changes, for me, remind me of when I was a boy in my father's garage. I distinctly remember the lighting when he spoke to me about how impressed he was with the mechanic who wears a white lab coat. He told me how he himself came home from work, wearing his white shirt and IBM tie, and would change the oil in the caddy without getting a spot. The quintessential German engineer to the last.
Since that wide-eyed day, my aspirations to emulate my father and his oil changes took on a nostalgic, Pirsig Zen gravity of ritual and performance very dear to me.
It's almost saddening to know I'll be doing less of them.

So now the quote:

Richard Feynman said, "Physics is like sex ... it may give some practical results, but that's not why we do it."

He developed the theory of quantum electrodynamics, which helped explain the relationship between light and subatomic particles. He won a Nobel Prize for his work in 1965.

~He also was involved in the Manhattan Project to help develop the first nuclear weapon.~

[brahma]

Wasted oil at 2000 mile intervals? Who cares. I hope the oil is in "new" condition every mile I ride- iit deserves it. I'd put Dom Perignon in it if it would take it.

[HFbmw]

Always looking for advise, learning is a great tool, eh?
I have the 91k100lt which has over 130,000 miles under its wheels.
When riding around town the oil will either seep due to riding in temps hovering around 30 degrees or it will smoke some from sitting on its side stand. Hence the site glass is always looked at.
Automotive engines take the same amount of oil as this K bike. 1 gallon and hard use of in town or cold weather will take a toll on oil.
I had been somewhat concerned of late. The oil would drop a pint in 1000 miles but when thinking of a gallon of the slippering ooze, what's a pint?

Last week I headed west to California. Changed oil before the trip and ran that bike for 28 hours. Amazed that the oil site glass stayed "full" for the first 1400 miles. Thursday May 10th I rode the last 700 across the Mohave desert and then the oil dropped to the pint.

Touring miles in the summer is far better than traffic riding! In more ways than oil consumption... heh

tim lindstrom