Hello,

As nowadays technology advances very quickly and all kinds of oil types are developed everyday, I want your opinion about what oil type, manufacturer etc i should use for a 1991 BMW K100.

I know that there are some topics on this, however they are old, dated from a lot of years back and may be old solutions.

Most of the guys recommend 15w50 for an (average) hot climate. I am living in Romania and nowdays i am riding mostly throughout the year (maybe 9-10 months), so I would say an average temperature will be about 20 degrees, with a lot of very hot summer days (30 +). 

Anyways, i was thinking about a Motul 5100 15w50 4t technosynthese ma2. What do you think about this?  

I am also specifying that milage of the motorcycle is quite high. I am not sure exactly how high because a few years ago the speedometer (including odometer) stopped working, and now it's working from time to time and I am not sure about how many miles it exactly has. I would think about 100k kilometers or somewhere there. Also the motorcycle oil was not changed for a long time now, the motorcycle was not riden for a few years and now I'm trying to make it run good again.

Also, I am interested in changing the oil filter, and I was thinking about a Hiflofiltro HF163. 

I also came across this "kit" for an oil change which seams suitable (the website seems to be "supplier for motorrad"). https://www.euromotoelectrics.com/product-p/oilchange-kb.htm?CartID=1
However the delivery for this kit in my country is above $100 and it's not suitable. But, if you think that the parts would be more suitable than the hf163 with motul 15w50, i might be able to procure them individually.

Thanks in advance!

If your bike is a daily driver and not being exposed to the stress of racing it hardly matters what you use.  If you are racing a high output engine you need to look for the oil with the highest film pressure rating to avoid damage to the cam lobes which are the most sensitive parts of the engine for wear.

Almost any brand name oil will work.  Current wisdom on engine lubricating oil suggests that 10W30 is the optimum viscosity for virtually all applications.  As long as you stick to a replacement schedule of 1 year or 5000 miles/8000km your daily driver engine will be fine.

Filters are pretty much the same.  Check a few videos on YouTube where they are cut apart.  There are only a few manufacturers of oil filters and they private label for most of the companies that sell them.  Because of the way it's mounted, the drain back valve is unimportant and it is extremely unlikely that if you change the filter regularly the element will clog up enough to open the bypass valve.  Just look for a filter that has the element securely attached to the end plates and a filter rating of about 20 microns.

The only brand I would avoid is Fram which has had a bad reputation for years for shoddy manufacturing and substandard filter media(an important filter part that is almost never tested).  Beyond that, it's really a question of availability and price as to your choice of filter.  You can use almost anything on the market if you change it at the 5000mile/8000km interval.

Oils are advancing today because engines are advancing today with lighter material, closer tolerances and polished surfaces. Your Brick's engine hasn't advanced one bit since it was manufactured. 15-50 with a Hi-Flo 163 will do the job—no sweat.

Actually, the brick engine is still mechanically pretty state of the art.  But for the early to mid 80's vintage engine management system, it would still compare favorably to the modern engines produced today. 

Witness the extremely high mileage that is reported on these engines compared to automobile engines of the era.  Durability wise, the brick is easily the equivalent of the modern automotive internal combustion engine.  It is only in the primitive Jetronic and Motronic systems where the technology has advanced beyond what our bikes have.

Point-Seven-five wrote:Actually, the brick engine is still mechanically pretty state of the art.  But for the early to mid 80's vintage engine management system, it would still compare favorably to the modern engines produced today. 

Witness the extremely high mileage that is reported on these engines compared to automobile engines of the era.

Oh, yeah? My '63 VW microbus got an easy 150,000 miles with only three engines.

I use a 50/50 mix of Mobil 1 15-50 and Mobil 1 High Mileage 10-40 is all of my Ks. 10K mile change interval since the oil is synthetic.

The high mileage oil has additives to rejuvenate seals - like the main seal and water pump shaft seal.

K bikes do not need special motorcycle oil because they have a dry clutch. You can use plain old car oil. Motorcycle oil is made for bikes that share oil between the engine and a "wet" clutch. You can't use car oils in a wet clutch bike because they have additives that would make the clutch slip.

I use Bosch 72161 oil filters. It is different from the Bosch 72161WS which is 2mm smaller in diameter.

Laitch wrote:

Point-Seven-five wrote:Actually, the brick engine is still mechanically pretty state of the art.  But for the early to mid 80's vintage engine management system, it would still compare favorably to the modern engines produced today. 

Witness the extremely high mileage that is reported on these engines compared to automobile engines of the era.

Oh, yeah? My '63 VW microbus got an easy 150,,000 miles with only three engines.

My '66 Westphalia needed a second engine at 70,000 miles. 

VW...   Hitler's revenge...

Come on, Katsawa, you seem to be very impatient to spoil in bullshit oil the money you'll need soon to change the flywheel gasket that will leak a few kilometers after your K100 starts again after a long sleep...
And why the hell do you want to buy parts overseas as you live in EU?
First, good new: most of OEM parts are available at any BMW dealer, even car dealers. Use realoem.com to find the reference.
Second: they're usually cheaper than anywhere else.
Yet, some independant dealers are sourcing aftermarket parts cheaper. But the quality is rarely the same.
Note an exception and a good adress : https://www.tills.de/

You don't need synthetic oil in such a peaceful engine. You'll never rev at 12000 rpm and romanian roads won't allow you (neither police will) to ride as quick as we used to ride when the K100 was a recent bike. Believe me, I've used many K75, K100 and K1100 as a customs motorcycle officer, with a total impunity about speed limits, our cruise speed was about 180 km/h all day long, with sudden cold starts: you don't need special oil.
15w50 is the recommended grade, at least until the temperature passes under -20°C. But you'll never ride under -20°C.
Personnally, I use Mannol SAE 15W50 semi-synthetic oil, I buy a 20 liter barrel once a year and it's perfect for all my bikes (except the ones with oiled clutch or the racing ones). Less than 3€/L.

La revedere!

Thanks for the replies and infos  

Au revoir

my vw devon camper 1980 2ltr air cooled 176,000 miles bottom end has never been apart and heads rebuilt once (which is a simple job on VW engines)  , change the oil and filters and some engines will out last their owners , neglect is the problem and lack of very basic upkeep , its a shame grease nipples went out and for me indicated the throw away car/bike situation we now have to live with .

Bog standard oil and frequent changes - every time!

I have a Ford Ranger. The published oil change interval is 20 thousand miles. I'm very cynical. IMHO that's got to be comfort-washing for stingy fleet managers. The scheduled service intervals are designed to get the vehicle to the 3-year mark when it's time to replace the fleet , at minimum cost. They are not designed to get the vehicle to that age in the best possible condition. Plus, the oil life computer on the thing has just told me to change the oil after 9 thousand (they provide a button to press to reset it, if it bothers you) Who are they kidding with these super-long service intervals?

Apart from that grumpy comment, it's a lovely morning. Enjoy the day everyone!

Suzi Q wrote:Bog standard oil and frequent changes - every time!

I have a Ford Ranger. The published oil change interval is 20 thousand miles. I'm very cynical. IMHO that's got to be comfort-washing for stingy fleet managers. The scheduled service intervals are designed to get the vehicle to the 3-year mark when it's time to replace the fleet , at minimum cost. They are not designed to get the vehicle to that age in the best possible condition. Plus, the oil life computer on the thing has just told me to change the oil after 9 thousand (they provide a button to press to reset it, if it bothers you) Who are they kidding with these super-long service intervals?

Apart from that grumpy comment, it's a lovely morning. Enjoy the day everyone!

So true. 

Oil life is determined by the depletion of the additive package in the oil.  Heat and oxidation "burns off" the anti wear, anti-foam, and detergent added as well as breaking down the molecular chains that provide the film strength.  Regardless of the marketing, nearly every oil will be "worn out" and have lost nearly all it's important lubricating qualities some time between 5,000 and 7,000 miles.  Even if it hasn't gone that distance, after a year it will have begun the oxidation process that damages the chains.

The maintenance schedules of most modern vehicles seem to be aimed at just getting through the warranty period without a major mechanical failure.  This is because there is some competition among manufacturers as to reducing the cost of ownership for their more tight-fisted customers.

A similar situation exists for oil as well.  Some of the sellers of synthetic oil have been applying high markups on their product for nearly 40 years and, as the price competition stiffens in that market segment, are resorting to recommending longer service intervals to justify their prices to more price sensitive customers. 

Bottom line is, as Suzi mentioned, bog standard oil and filters on a 5,000 miles/8,000 km service schedule is all your engine needs.  You can spend more, but you don't have to.

Don't use unknown-name or no-name brands. I once got a no-name oil filter (made in China) next oil and filter change I opened it up, the paper filter element had holes in it, won't do that again.

On a cold winter morning in Romania (even in Victoria I think) when the oil is cold and thick, the bypass valve should open, not a big deal depending on its location.

For decades I've used bog standard oil, filters and service intervals, to me that means Castrol 20 W50, Ryco filters, 10,000km service intervals. Ryco filters are made in China for years now, but still good.

One exception, my previous car, on LPG, an experiment, bog standard oil and filters, but non standard oil changes at 50,000km intervals (100,000km at least once) after installing a bypass filter. Got well over 600,000km on original engine, which then failed for a non oil reason. Did some reading up about oil before I installed it, my take away messages (which could easily be wrong) were that oil test fail reports were mostly due to TBN, total base number, relating to additives to minimise acid problems. The bypass filter used a toilet roll as the filter element. When sulphur combines with water you get sulphuric acid. You get this when the sulphur from oil combines with condensation. A normal filter can't absorb much water cause the element is only about 1mm thick.

daveyson wrote:One exception, my previous car, an experiment, bog standard oil and filters, but non standard oil changes at 50,000km intervals (100,000km at least once) after installing a bypass filter. Got well over 600,000km on original engine, which then failed for a non oil reason. The bypass filter used a toilet roll as the filter element.

I remember those from my JC Whitney catalog back in ancient times! I often perused it for miracle products that would enhance my first auto—a 1959 two-door, English Ford estate wagon, bless its heart. The most compelling at that time were the toilet paper by-pass oil filter, the water injection system, and Ring Job In-A-Can (for emergencies, maybe). I decided instead on a two-burner Coleman white gas stove and a small chest for storing it.

Anyway, they're still manufactured and the product is discussed at Haggerty's. The answer to the question posed in the article's last paragraph is a bidet.

Can't read the link. One of the ones I used to install even had a BMW logo on it.

daveyson wrote:Can't read the link.

It's working on my Mac up in the woods. Come on over.

15/40 Mobil semi-synthetic for the Royal Enfield, 20/50 Halford's (actually Morris) Classic dinosaur pee for all others.

Except that five litres of 15/40 Mobil semi-synthetic cost me fifty fckn quid today and that was with "twenty percent extra free!" WTFFF!!!!!!!!!!! Twice the price and more compared to the dinosaur pee. Change interval? 3200 miles. Well, RE, go ffffffffffff take a long walk off a short pier. 6-8000 miles is going to be more like it because the bike is rarely ridden hard (hard? A Royal Enfield Bullet?). Well, maybe yesterday. A small group of us went out for a ride - a 1964 Triumph T120 Bonneville, a 1966 TR6C Scrambler, a 1937 Velocette MAC, a 1954 Velocette Thruxton and me; it started off reasonably sedately but fairly quickly turned into some 'spirited riding'. I even got passed the Thruxton at one point because he braked for a bend and I didn't, but to be fair, I did have the better tyres. That was a FUN day out, in big letters.

Ahem. Back to K100 and oil grades...

What's your Bullet?

daveyson wrote:Can't read the link. One of the ones I used to install even had a BMW logo on it.

I can't give it up.
Here's the video followed by a before-and-after still. It's oil filtration keeping up with the times!

Early Holdens grey motors didn't have oil filters. You could however by a aftermarket by-pass filter that used rolls of toilet paper. I don't know whether Sorbent or Kleenex was better.
Regards Martin.

jbt wrote:What's your Bullet?

It's a new one - a 2020 model (see sig) and one of the very last Bullets. RE stopped producing them in August 2020 (couldn't get big singles to meet Euro 5 regs) and I bought mine in September. I had a 1953 350 about 40 years ago but it used to eat clutch pushrods, so I got rid of it. Ironically, I was born in Wednesfield which is not that far from the Royal Enfield factory in Redditch.

OK;
I've ridden a 500 Bullet for years, one of the last with the iron barrel but already a 5 speed gearbox and an electric start.
I've enjoyed as much this bike as I hated it for its numerous failures.
Eventually, after 4 pistons changes, I stripped down the engine, re built it new from the rod big end and sold it.
The buyer rode it one year before the crankshaft breaks.
I bought instead a 500 electra EFI, this time one of the 1st UCE engines imported in Europe.
Does not break, but the pleasure is not the same...

i have a 250 , i took the 5 speed out and replaced it with a 4 speed box , i live 3 miles from where they where built but never see one on the road , one day i will get a 500 bullet as they are quite cheap here now .

jbt wrote:Does not break, but the pleasure is not the same...

Yes, but at least you can thrash the nuts off it and be fairly sure of getting home afterwards!

firstle wrote:i have a 250 , i took the 5 speed out and replaced it with a 4 speed box

Oh yes; the Crusader grenade looking for somewhere to explode.

continental GT , the off the shelf cafe racer for the 17 year old , no wonder they went bang , thrashed and no maintenance , good bike and fast for a 250 with a weak gearbox (5 speed) and fibre glass tank , far to small if your over 6 foot , mine does not leak oil ? i know most did , i must look to see if theres any in it .

Franz used to be expensive, but good I think, I even like the shield type label. I think they're a good idea, many don't believe in the extended oil changes, but if you install one you can still do oil changes at normal time intervals if you want. They take a lot of condensation and crap out of the oil, plus sub 20 micron, which some say is a major cause of wear fro crank bearings for example.

Here's one of the types I've installed, these parts could all be got at the wreckers for about $20, that was years ago though. LPG hydraulic fittings and hoses, and a restrictor tapped into a Camry manifold barb. A plate bolted onto a BMW oil filter housing to convert it to a bypass filter.

Actually this was the one I wanted to photo, with the hoses still connected. I usually put a T on the oil pressure sensor for the oil supply, and the oil return line going through the oil filler cap. The restrictor being tapped into the barb for the oil return line at the filter.

daveyson,
thank you for your input.

I was given a Trabold bypass filter a few years ago:



It still has to be installed.
too many projects, too little time

If you're going to T in from the oil pressure sender, keep in mind this easy to fall for trap, the large diameter of the sender requires a large diameter spanner, so it's easy to forget the pipe is of small diameter so it's easy to overtighten.

thank you for the advice, very appreciated

It might end up being a little like my situation, when I finally got around to doing it I said to myself, daveson that was so quick and easy you should have done that ages ago.

The routine I settled in to was to change the normal filter and oil every 50,000km, and changed the bypass filter every 15,000km (much longer and it would block up) That meant another litre of oil, so that would help with the worry about the additives.

I really should install it on my current car, it's on the to-do list.