Hi all,

Sorry this question has probably been asked already but just getting used to the forum and still working out how to use it on my phone!

What engine oil to use on 1992 K1100LT?

-manual suggests 5W50 which is a bit harder to get, a couple on eBay.

-off the phone from BMW dealer parts, after some time they said to use 15W50 which they supplying for about £17/L

I'm looking to travel through europe in August 2020, my concern is the temperature as I've noticed it had risen when I'm standing still on the bike. Is this normal for the K bikes? As soon as I move off the bike temp drops again to avg. In Scotland it's fairly cold but abroad italy this year was as high as 38C ! :S

Thank you in advance for any advice.

MarcoCrolla wrote:

What engine oil to use on 1992 K1100LT?

Well you have posted the answer under your question...
Do you ride under 0°C? Probably not, so any viscosity index under 20W40 is useless and can cause excessive oil consomption and low oil pressure.
Do you ride to 40°C? You probably will in summer in Europe.
So the only answer is to use 20W50 oil.
Note that the common 10w40 won't allow you rides above 5°C and that the also common 15W50 is OK until 30°C.
That's the oil I use in my K11, but it's a winter bike only.

Thanks for your response !

Just beginning to understand the differences of oils and workings of the bike

The first number does not really matter, but the higher it is then the longer the oil will take to get around the engine on start up. With the dry clutch and separate gearbox oil, any car oil is absolutely fine. I use a 15/40 in the south of France all the year round.
Note, that the table from your manual was written 30 years ago when oils were very different.

I'm afraid you're wrong. The first number, before W, is the cold viscosity: it determines the lowest temperature the oil can be pumped into the lubrication system. The second, after the W, gives information about the thickness of the oil fil in warm conditions. The higher it is, the best protection oil gives to mechanical elements - but creates counter forces.
Each number refers to a different scale with specific procedures to measure viscosity:
-in CSp (Centispoke) for dynamic viscosity (cold conditions, number before the W)
-in CSt (Centi Stokes) for cinetic viscosity (warm conditions, number after the W) 
-a viscosity index that gives information about the viscosity stability at different temperatures .
Oils are very slightely different today in their composition, but their viscosity remains exactly the same as it's determined by  norms. A 20W50 from 1990 has the same characteristics than the 2019 20W50.
A 15W40 is ok in the south of France for the cold viscosity, but probably way too much fluid in warm conditions as it should not cope with temperatures more than 20°C - this applying only to the K1100 engine. As this engine is prone to overheating, I strongly recommend a 20W50.
Most of complaints about oil consumption is due to a wrong oil index use.

Yes it's normal that the temperature is higher when stopped, while moving there is more air passing through the radiator to help in cooling. You haven't said though, how high it goes, how quickly and whether it's from a cold start. When you say average,  does that mean the needle is in the middle? On my bike the needle normally rests at one quarter from the cold position.

I guess you won't want to ride below -10 Celsius, or above 40, so 20W50 is good. But your guess is better than mine for European weather.

Hi, thanks for the responses.

At the moment I have been riding in temps between 5-18C in Scotland.

I've noticed after about 40mins of riding that the bike begins to warm up, increase in tempt I'm about 5-10mins and goes into the top end of the temp gage. But immediately goes back to the middle once I start moving.

I am just a bit concerned how quickly the temperature can rise, my plan is to travel europe and go to Italy in August 2020. This year was about 38C at the hottest in southern Italy and I was worried that the bike would just heat up straight away when traveling slow or at a stop.

Hence why I'm looking for an oil which will cope with these conditions.

BMW recommended 15W50 but I guess that's only because it's the oil they have available and the guy had no idea about the K1100LT.

I'll probably get this though from bmw.

Sorry , at work and last message didn't make much sense.

Basically the bike begins to increase in temp at a stand still.

I just want to make sure it basically doesn't explode whilst I'm in hotter country's...

Overall the bike seems fine

I'll say that's too high and too quickly. Give it a full service with extra attention to the cooling system especially flushing.

From the chart 15W50 is good if you don't want to ride with the temperature above 30.

MarcoCrolla wrote:Basically the bike begins to increase in temp at a stand still.

If the engine were approaching overheating, the fan should start start running to stabilize the temperature. Do you know if the fan operates? Have you tried to rotate it using a dowel or screwdriver when the engine isn't running?

Thanks, yes I will look to do this and see if it makes any difference

@laitch to be honest with you I didn't even know it had a fan, and I don't recall ever hearing it either unless I just can't over the noise of the bike.

I would imagine it's at the front end of the bike? I will give it a look tomorrow and see if it functions or not!

Check that the radiator fins are clean and clear of debris. If blocked do not clean with high pressure air or high pressure water. Check that a thermostat is fitted and functioning. What is the condition of the coolant, when was it changed last. Never use non distilled water in the cooling system, use a good quality compatible coolant  mixed with distilled water.
Regards Martin.

@MartinW yeah I will have a good look, seems like there is plenty I could get on with, with the bike.

I'll look to do service the bike myself and get other components checked .

Cheers

MarcoCrolla wrote:@laitch to be honest with you I didn't even know it had a fan, and I don't recall ever hearing it either unless I just can't over the noise of the bike.

I would imagine it's at the front end of the bike? I will give it a look tomorrow and see if it functions or not!

If you haven’t heard the fan, there’s a good chance it’s not working, especially at the temp you show in your picture. It’s directly behind the radiator. 
My first K100 had the brush holders melted, probably from the bearings running dry over the years and either seizing or running slow. New fan motor (from EME in USA, from memory) and all is good. Genuine BMW is fine if you have a large and masochistic wallet. My replacement was the same Bosch unit but without a BMW label, so much less $$. 
All being equal, fan only ever comes into play when not moving. Almost any forward movement will provide enough air for proper cooling, even with Aussie summer temperatures. 
Others have replaced the fan completely with an aftermarket one, though that involves some fabrication to mount it. Probably better solution, but more work to install. 

Also possible is that the thermoswitch in the cooling system has failed, but statistically less likely than the fan motor. 

Good luck.

Bill

I wouldn't worry about  it unless the overheat light in the cluster comes on.

Thank you Bill. Yeah I haven't heard it whilst stopped...

And,

Duck, I like your thinking. Not to worry till the lights start flashing! Ahah.

jbt wrote:I'm afraid you're wrong. The first number, before W, is the cold viscosity: it determines the lowest temperature the oil can be pumped into the lubrication system. The second, after the W, gives information about the thickness of the oil fil in warm conditions. The higher it is, the best protection oil gives to mechanical elements - but creates counter forces.
Each number refers to a different scale with specific procedures to measure viscosity:
-in CSp (Centispoke) for dynamic viscosity (cold conditions, number before the W)
-in CSt (Centi Stokes) for cinetic viscosity (warm conditions, number after the W) 
-a viscosity index that gives information about the viscosity stability at different temperatures .
Oils are very slightely different today in their composition, but their viscosity remains exactly the same as it's determined by  norms. A 20W50 from 1990 has the same characteristics than the 2019 20W50.
A 15W40 is ok in the south of France for the cold viscosity, but probably way too much fluid in warm conditions as it should not cope with temperatures more than 20°C - this applying only to the K1100 engine. As this engine is prone to overheating, I strongly recommend a 20W50.
Most of complaints about oil consumption is due to a wrong oil index use.

Oh thanks for all that. I am a complete idiot and have never had anything to do with engineering for the whole of my life. 
I shall not bother ripping some of your points to bits, my time is far too valuable.

I appreciate all the above comments.

Coolant looks fine if anything it's been over full.

Still have no idea where the fan is...there is a noise where the tank is if it's at the top end unless that's just the noise it makes where it takes the fuel in...sorry I sound dumb but I couldn't see the fan in the booklet.

BobT wrote:

jbt wrote:I'm afraid you're wrong. The first number, before W, is the cold viscosity: it determines the lowest temperature the oil can be pumped into the lubrication system. The second, after the W, gives information about the thickness of the oil fil in warm conditions. The higher it is, the best protection oil gives to mechanical elements - but creates counter forces.
Each number refers to a different scale with specific procedures to measure viscosity:
-in CSp (Centispoke) for dynamic viscosity (cold conditions, number before the W)
-in CSt (Centi Stokes) for cinetic viscosity (warm conditions, number after the W) 
-a viscosity index that gives information about the viscosity stability at different temperatures .
Oils are very slightely different today in their composition, but their viscosity remains exactly the same as it's determined by  norms. A 20W50 from 1990 has the same characteristics than the 2019 20W50.
A 15W40 is ok in the south of France for the cold viscosity, but probably way too much fluid in warm conditions as it should not cope with temperatures more than 20°C - this applying only to the K1100 engine. As this engine is prone to overheating, I strongly recommend a 20W50.
Most of complaints about oil consumption is due to a wrong oil index use.

Oh thanks for all that. I am a complete idiot and have never had anything to do with engineering for the whole of my life. 
I shall not bother ripping some of your points to bits, my time is far too valuable.

Please go on! Rip him a new arse!

MarcoCrolla wrote:Still have no idea where the fan is...there is a noise where the tank is if it's at the top end unless that's just the noise it makes where it takes the fuel in...sorry I sound dumb but I couldn't see the fan in the booklet.

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Fan under that front fairing behind the radiator
Good luck with moto

@volador thanks !

MarcoCrolla wrote:Coolant looks fine if anything it's been over full.

Coolant, engine oil and gear oil should not exceed their marked levels. Remove the coolant reservoir cap and remove excess until the level is between Min and Max when the engine is cold. If you are riding the moto, this process might need to be done a few times until the level stabilizes.

Worried about roasting the cojones in the summertime upgrade to Spal fan, add fan switch and add insulating blanket under tank and seat




Baker Air Wings  Reply #3
http://www.motobrick.com/index.php/topic,1355.msg6216.html#msg6216

Spal fan  https://www.tills.de/product-112-113-158.html

@Laitch ok I'll get this done, whoever done the last service (at a garage too from the paperwork) done a rushed job because I can't even see the oil level as it must be over full and just looks clear at the reader on the side of the bike.

I have checked to see if oil is present.

Bought a service kit and will be doing it in a few days once I'm off!

@volador

MarcoCrolla wrote:Duck, I like your thinking. Not to worry till the lights start flashing! Ahah.

That's a good belief system if the lights are able to flash, but if there is no bulb or the bulb isn't connected to a functioning warning system, it could leave you hitchhiking, which can be a good way to meet interesting, bizarre or malevolent people.

Ahah very true ‍�

Get someone competent to tilt the bike left and right while observing the oil level sight glass.
Regards Martin.

MartinW wrote:Get someone competent to tilt the bike left and right . . .

I think it's easier to find competent people who either know their right, or know their left. Finding somebody who knows both might be asking too much.

@MartinW thanks, I think it's so full that it's way above the reader just like the coolant was. a service kit has arrived today so I'll look to get new oil from BMW and just change everthing since I don't trust that the last time it was serviced (June 2019) was any good and any components where actually change other than topping everything too full.

Cheers!

P.s It might be hard to find anyone competent round these parts ahah

If planning to install fan switch reply#8 & 11 will give you idea where to wire tap into

Re: Summer Planning for BBQ'd K-thighs

I should have added strong to the competent . You don't want them to drop it on your head while your checking the level.
Regards Martin.

Thanks for adding the details about the fan. I'll do a bit of digging into that and will start to service the bike tomorrow!

If your moto has ABS

DUCKS's way to use ABS Switch as fan switch in K1100

"Another possibility is that a prior owner added a fan switch that you don't know about. I've made ABS switches that double as a fan switch.  The down position is a momentary switch for the ABS and the up position is a non-momentary switch to turn on the fan.

Look in the relay box.  If there's a non-factory wire tapped into blue/yellow wire to the fan relay then grounding that turns the fan on."

Laitch wrote:

MarcoCrolla wrote:Duck, I like your thinking. Not to worry till the lights start flashing! Ahah.

That's a good belief system if the lights are able to flash, but if there is no bulb or the bulb isn't connected to a functioning warning system, it could leave you hitchhiking, which can be a good way to meet interesting, bizarre or malevolent people.

Why would there be no bulb?

And on the incredibly rare (I've never heard of it) chance the bulb does not illuminate then the radiator cap will blow (just like a car except it goes all over your left leg) to let you know that the system is overheated before the engine is damaged.

I've had several old K bikes with heat issues (bad fan or radiator cap) and never walked or hitchhiked.  On a couple of them I was over 1,000 miles from home when I discovered the issue and still rode them all of the way home. You have to work pretty hard to damage one of these bikes by overheating.

Have you ever heard of a single K bike that died due to overheating? I never have.

I've heard of a couple catching fire, does that count as overheating?
Regards Martin.

In the ~two years I've been brick riding, I have read of a few catching fire, but then they survived. I havn't read about any dying from overheating.

Fan in my K100LT died and I just killed it in city riding to stop it over heating, it was fine.

Same in my K100RT, was out for over a year and only changed it when I was going to France because I knew I would be meeting 35c and you definitely need a working fan for that.

Key thing is watch for your warning light, fan should always come on first.