BMW k75C @ 132,000 OA

[ammolab]

My bike since new... Daily driver using Mobil 1 15W-50 or Turbo Diesel Truck 5W-40 for a long time. Oil Interval is 4000miles or 1 year which ever comes first. Bike's sump holds 4 quarts and has a dry clutch and a seperate Gearbox...should be EASY on the oil!

High Iron and chrome?? There is no Iron in the block/cylinder so did this all come from the rings? Chamshafts? Timing Chain? I am not too worried as I have never added a drop of oil to the bike in 25 + years between changes. What do you think?

 

[addyguy]

Ouch. You took TDT, a 'stout' 5W-40, down almost to a 20-weight.

I don't think it looks too bad, for a bike.

 

[dparm]

Agreed, your bike is really beating down on that oil. Doesn't mean the engine is having issues. Are you a common-sump setup?

PS -- might want to black out your phone #/addr/email addr.

 

[ammolab]

Originally Posted By: dparm
Agreed, your bike is really beating down on that oil. Doesn't mean the engine is having issues. Are you a common-sump setup?

PS -- might want to black out your phone #/addr/email addr.


Gearbox is Separate...does not share lubrication with the engine....as I said in my original post:

"sump holds 4 quarts and has a dry clutch and a separate Gearbox...should be EASY on the oil!"


I went back to edit that picture with a "sanitized" version but forum would not allow edit (edit time expired).

 

[ammolab]

Bill: thanks for the edit on that Oil Report!

 

[KernelK]

Your UOA report is certainly a good argument for going back to the manufacturers recommended viscosity of 20w-50. My 1985 K manual only recommends 10w-40 oil for 40 degrees F and below. The K bikes of that vintage did not come equipped with oil coolers, possibly a reason BMW specified the heavier viscosity.

I think you were right on the money using M1 15w-50, especially in Texas.

 

[ammolab]

Originally Posted By: KernelK
Your UOA report is certainly a good argument for going back to the manufacturers recommended viscosity of 20w-50. My 1985 K manual only recommends 10w-40 oil for 40 degrees F and below. The K bikes of that vintage did not come equipped with oil coolers, possibly a reason BMW specified the heavier viscosity.

I think you were right on the money using M1 15w-50, especially in Texas.


Not sure it is a HEAT thing...I have an Oil Temp Gauge and With that 4 quart sump my temp has always been below 205F.

 

[sunruh]

many questions to ask of the report.

365 flash is pretty low. even for 0.5%

susvis is on the floor. he77 is it only 0.8 above being a TWENTY WEIGHT!!! a 20wt!!!

nice job thrasher!!!

is 28 iron high? hard to say.
look at the other values.
silicon was low. very nice air filters! so you are not grinding it up via air sandpaper.

copper 5 is fine, probably.

lead 1 ?
nickel 3 ?
really or merely background scatter?

i'm not a fan of 5w40 in shared sumps. ah, but you say yours is NOT. so.......how did you kill it with just a crank and cams?
is that chain driven cams or gear?
bucket over shim or what?

is the extremely low vis causing issues? maybe not in the first 1000 miles, but probably the last 1000.

imho, either try the same oil at 3000 or switch and run the same 4k.

 

[ammolab]

DOHC driven by chain, coin type shim in bucket under the cam. Aluminum Block with Nikasil coating (no steel liner).

I have been running that TDT M1 oil for a couple of years but now that LOW Vis has me running Mobil 1 15W-50 again. The 15W-50 was my oil of choice for maybe the last 15 years. I will test this oil after 2 or 3 thousand miles just to see what's up.

Not to worried...I have 25 years and 132,000miles on the bike. I got my money's worth!

 

[sunruh]

yes with 132k miles you have ridden the wheels off it.

i would go 3k if you can before sampling.

did you put in silver cap or gold?

for me, red cap didnt even hold up, so i will be very interested in your results. hopefully it will at least be a high 30.

 

[Craig750]

Originally Posted By: ammolab
Originally Posted By: KernelK
Your UOA report is certainly a good argument for going back to the manufacturers recommended viscosity of 20w-50. My 1985 K manual only recommends 10w-40 oil for 40 degrees F and below. The K bikes of that vintage did not come equipped with oil coolers, possibly a reason BMW specified the heavier viscosity.

I think you were right on the money using M1 15w-50, especially in Texas.


Not sure it is a HEAT thing...I have an Oil Temp Gauge and With that 4 quart sump my temp has always been below 205F.


What about small hot spots that may degrade the oil but not effect the overall oil temperature?

I don't know enough about that model engine.

If the oil is thinning out a lot, might be worth trying the M1 V-Twin 20w-50.

Decent mileage on your bike.