Mobil 1 "oil solvent" 15W-50 4000miles BMW K75C

[ammolab]

High Iron again (34) on 15W-50 silver cap vs 28 on 5w-40 TDT last run. The TDT cut down a bit and this oil ended up about a 10w-30 so I am trying Valvoline VR1 20w-50 this time and may try Redline after that. I want to see if I can find a shear stable oil for 4000 or so miles. Not sure about the iron. NO gears or clutch in the oil and the block is Aluminum with NikaSil liners. The only oiled iron is the valve train, cam chain and gear driven oil pump and balancer shaft. It is a 4 quart sump for a 750cc "automobile type" engine...should be easy on the oil!

I live and work just off the interstate. I wonder if a half mile run before I hit 70mph/5000rpm is enough to lube the cams? I would think everything is oiled well by then, no?

 

[HTSS_TR]

There is a FAR for 6 quarts Valvoline VR1, looking for a post about Valvoline FAR in the rebate sub-forum.

 

[spackard]

Googled a little and found someone's '87 K75S UOA here:
http://www.eilenberger.net/K75S/C21138.pdf (circa 2004)
Same Mobil-1 15W-40.
Just looking at these two it appears you have something wearing,
or, pure speculation, oil was reformulated. Guess it's easier to change to VR1 Racing Synthetic (since that's close to free after rebate deal on now) then it is to pop it open and start looking for what's wearing.

 

[dtt004]

Hi.

It's not the oil. Oil shear can happen at any rate because there are many factors that dictate this rate. I guarantee that if you switch to the next oils you mention, you will not see a difference (significantly conclusive). I am sure that it's more of the driving conditions and driving habits, engine design and engine condition. I obviously do not have your engine broken down so I can see what it looks and operates from the inside, but I am confident that its those factors that you are seeing affecting oil stability. Check those first, but of course, changing oil is always a valid solution. However, I am also sure that doing so will not yield any conclusive differences.

 

[ammolab]

I'm sure something is "wearing".... the bike is 25 years old and has 136,600 miles on it. I have run Mobil 1 for about 20 years in this bike so the combo of oil and engine have to be a little 'compatible' I would think.

 

[ammolab]

Originally Posted By: HTSS_TR
There is a FAR for 6 quarts Valvoline VR1, looking for a post about Valvoline FAR in the rebate sub-forum.



6 quarts of SYNTHETIC VR1 rebate here: http://www.valvolinevr1racingoil.com/

 

[Trav]

Quote:
I live and work just off the interstate. I wonder if a half mile run before I hit 70mph/5000rpm is enough to lube the cams? I would think everything is oiled well by then, no?


Thats a good question.
I lived about the same distance from highway when i bought my first big Honda bike back in 83 and like you right out there at 5K RPM.
Cams let go at 12K i sold the bike shortly after and moved into the more suburban setting.
Fast forward to 93 i bought another bike and lived 1/4 mile from the highway and same thing happened again.

I was told by Honda the oil was not up to temp and i was damaging the cams running the engine by running these RPM's too soon.
I installed an oil temp gauge and low and behold oil temp was cold for what seemed to a long time.
I began to take a longer route to the highway keeping the revs lower until the oil was good and warm before hitting the highway.Bike went 160,000 Km with more more issues.
Draw your own conclusion.

 

[friendly_jacek]

"It is a 4 quart sump for a 750cc "automobile type" engine...should be easy on the oil!"

Wow, so much oil for a small engine! No wonder it stays cold forever.

Not sure how that explains viscosity break down though.

 

[ammolab]

I do have a temp gauge in my K75C sump and it reads rather COLD almost all the time. I can run 17 miles of interstate in the winter and temp is 120F. But the sender is in the BOTTOM of the finned, aircooled 4 quart sump...so I wonder if it is a true reading of 'circulating oil temp'.

 

[Trav]

The one i bought was a cheap one that went into the dipstick/fill hole effectively replacing the dipstick,i marked the full mark with a file swipe.
It was made well and got a pretty accurate measurement.
IIRC it was around $50 could you use one of these to compare?

 

[spackard]

I have a Luftmeister oil dipstick/temp gauge in my '83 R100RT (airhead with oil radiator).
Usually a little above 200F in the city in Southern California winter; 250F on freeway heavy traffic 90 degree day.

 

[ammolab]

Originally Posted By: Trav
The one i bought was a cheap one that went into the dipstick/fill hole effectively replacing the dipstick,i marked the full mark with a file swipe.
It was made well and got a pretty accurate measurement.
IIRC it was around $50 could you use one of these to compare?


Those dipstick items will not work in K bikes. They have an oil 'window' instead of a dipstick and the Oil Fill cap would not accept this kind of gauge as the oil takes a torturous route to the sump. You can't stick anything down that hole and reach the oil.

 

[ammolab]

Originally Posted By: spackard
I have a Luftmeister oil dipstick/temp gauge in my '83 R100RT (airhead with oil radiator).
Usually a little above 200F in the city in Southern California winter; 250F on freeway heavy traffic 90 degree day.


My Old R50/5 would reach 275F on a hot day. No cooler but I did put the optional 4qt. sump on that bike. I had the temp sender high up through the side of the oil pan just under the block.

 

[KernelK]

Pop the cam covers and take a good hard look at the cams. It won't take but a half hour or 45 minutes and could possibly give you some peace of mind. Does the bike consume any oil?

 

[ammolab]

Originally Posted By: KernelK
Pop the cam covers and take a good hard look at the cams. It won't take but a half hour or 45 minutes and could possibly give you some peace of mind. Does the bike consume any oil?


I Plan to look at the cams..valve clearance check is over due any how. Bike Uses no oil except for a 'weep' at the rear main seal, about 1/2 quart in 4000miles.

 

[ammolab]

Originally Posted By: ammolab
Originally Posted By: KernelK
Pop the cam covers and take a good hard look at the cams. It won't take but a half hour or 45 minutes and could possibly give you some peace of mind. Does the bike consume any oil?


I Plan to look at the cams..valve clearance check is over due any how. Bike Uses no oil except for a 'weep' at the rear main seal, about 1/2 quart in 4000miles.


Cams look like NEW! I did find one exhaust valve that was more than a bit tight..so it was worth it to pull the cam cover, thanks!

 

[kballowe]

Originally Posted By: Trav
Quote:
I live and work just off the interstate. I wonder if a half mile run before I hit 70mph/5000rpm is enough to lube the cams? I would think everything is oiled well by then, no?


Thats a good question.


I was told by Honda the oil was not up to temp and i was damaging the cams running the engine by running these RPM's too soon.
I installed an oil temp gauge and low and behold oil temp was cold for what seemed to a long time.
I began to take a longer route to the highway keeping the revs lower until the oil was good and warm before hitting the highway.Bike went 160,000 Km with more more issues.
Draw your own conclusion.


I agree.

It's interesting to note that my son's new Yamaha sport bike has a blinking area on the digital tach until it reaches some combination of water/oil temperature.

In the winter time it takes a long time for the tach to stop blinking.

 

[ammolab]

Originally Posted By: kballowe
Originally Posted By: Trav
Quote:
I live and work just off the interstate. I wonder if a half mile run before I hit 70mph/5000rpm is enough to lube the cams? I would think everything is oiled well by then, no?


Thats a good question.


I was told by Honda the oil was not up to temp and i was damaging the cams running the engine by running these RPM's too soon.
I installed an oil temp gauge and low and behold oil temp was cold for what seemed to a long time.
I began to take a longer route to the highway keeping the revs lower until the oil was good and warm before hitting the highway.Bike went 160,000 Km with more more issues.
Draw your own conclusion.


I agree.

It's interesting to note that my son's new Yamaha sport bike has a blinking area on the digital tach until it reaches some combination of water/oil temperature.

In the winter time it takes a long time for the tach to stop blinking.



What is the 'restriction' when the light is blinking?

 

[kballowe]

Originally Posted By: ammolab
Originally Posted By: kballowe
Originally Posted By: Trav
Quote:
I live and work just off the interstate. I wonder if a half mile run before I hit 70mph/5000rpm is enough to lube the cams? I would think everything is oiled well by then, no?


Thats a good question.


I was told by Honda the oil was not up to temp and i was damaging the cams running the engine by running these RPM's too soon.
I installed an oil temp gauge and low and behold oil temp was cold for what seemed to a long time.
I began to take a longer route to the highway keeping the revs lower until the oil was good and warm before hitting the highway.Bike went 160,000 Km with more more issues.
Draw your own conclusion.


I agree.

It's interesting to note that my son's new Yamaha sport bike has a blinking area on the digital tach until it reaches some combination of water/oil temperature.

In the winter time it takes a long time for the tach to stop blinking.



What is the 'restriction' when the light is blinking?


It's an RPM restriction.