I've read on several sites that letting your oil temp get over 250f, greatly reduces oil life. Read alot of uoa's for alot of bikes, and they never mention that the oil has been "overheated" and therefore is no longer serviceable.Every now and then, you see one that has thickened up from where it was designed to be, or has thinned out some.In an air cooled motor, does 310 degree oil temp mean it's shot?.,,
What does high oil temps really do to bike oil?
- Thread starter BigCahuna
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I run mobil 1 15w50 in my harley. I have never measured oil temps but in Charlotte stop and go traffic it feels like you are riding a wood burning stove in the summer. It does shear out of grade but nice wear numbers and tbn still good after 3500 miles. So for I refuse to pay the extra money for the motorcycle on the bottle.
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Excessively high temperatures expedite the oxidation and nitration of the oil, leading to additive depletion quicker.
High oil temperatures will also lead to scuffing and galling of metal parts due to the breakdown of the hydrodynamic barrier. This is probably the most critical aspect of overheating.
If you subject your engine to frequent overtemps then it's probably a good idea to go to a higher viscosity grade.
And yes, 310ºF is considered excessively high temperature if this is your sump temperature.
High oil temperatures will also lead to scuffing and galling of metal parts due to the breakdown of the hydrodynamic barrier. This is probably the most critical aspect of overheating.
If you subject your engine to frequent overtemps then it's probably a good idea to go to a higher viscosity grade.
And yes, 310ºF is considered excessively high temperature if this is your sump temperature.
I agree with everything FowVay states.
However before I would increase my viscosity of oil I would buy an oil cooler. If the bike already has one then add another or go larger.
However before I would increase my viscosity of oil I would buy an oil cooler. If the bike already has one then add another or go larger.
Originally Posted By: Roadkingnc
I run mobil 1 15w50 in my harley. I have never measured oil temps but in Charlotte stop and go traffic it feels like you are riding a wood burning stove in the summer. It does shear out of grade but nice wear numbers and tbn still good after 3500 miles. So for I refuse to pay the extra money for the motorcycle on the bottle.
This is what I'm Talking about. Nice wear numbers and a tbn, that still says it's good to go another few thou miles. As far as the labs that test oils, I've never read a report that said the oil was overheated and is no longer serviceable, but the flashpoint was from 395 -435 degrees.,,
I run mobil 1 15w50 in my harley. I have never measured oil temps but in Charlotte stop and go traffic it feels like you are riding a wood burning stove in the summer. It does shear out of grade but nice wear numbers and tbn still good after 3500 miles. So for I refuse to pay the extra money for the motorcycle on the bottle.
This is what I'm Talking about. Nice wear numbers and a tbn, that still says it's good to go another few thou miles. As far as the labs that test oils, I've never read a report that said the oil was overheated and is no longer serviceable, but the flashpoint was from 395 -435 degrees.,,
I have to think a positive UOA, low wear metals, good tbn, proper viscosity, and no insolubles are telling that high temps in air cooled engines aren't killing the oil.
Based on the UOAs I have done and others on this site, I am very comforatable changing oil in my air cooled bike every 5k miles. Maybe the life of the oil has been shortened, but it ain't dead at 5k.
Based on the UOAs I have done and others on this site, I am very comforatable changing oil in my air cooled bike every 5k miles. Maybe the life of the oil has been shortened, but it ain't dead at 5k.
I just wonder..... Does anyone know if the average motor oil flash point has risen in say, the last ten years or so?
In my mind, the flash point is an indication of how the oil will perform and how long it will stay in grade - in elevated temperatures. At the very least, many air-cooled motorcycle owners will seriously consider a higher flash point when selecting a particular oil.
Or is it just me?
In my mind, the flash point is an indication of how the oil will perform and how long it will stay in grade - in elevated temperatures. At the very least, many air-cooled motorcycle owners will seriously consider a higher flash point when selecting a particular oil.
Or is it just me?
I dont beleive flash points have changed much, just depends on the particular oil. Flash points above 450 degrees in low viscosity weights, normally shows in higher quality base oils.
Sheer is over rated, some would say a 30 weight that stays in grade is better than a 10w40 that falls out of grade, and is better for your motor, its just not true.
But some High end group 5 synthetics barely manage 450 degree flash point. Do the higher flash points allow for more sheer and dulition, that very well may be.
Sheer is over rated, some would say a 30 weight that stays in grade is better than a 10w40 that falls out of grade, and is better for your motor, its just not true.
But some High end group 5 synthetics barely manage 450 degree flash point. Do the higher flash points allow for more sheer and dulition, that very well may be.
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I think I need to get an oil temp gauge on my bike after reading this. I know the oil is very hot and cooking in my set-up.
I ride a 08 Heritage Softail, that is completely stock with an oil cooler. I've had the oil temp in the return tank reach 270 deg F, so I installed the oil cooler. It dropped the oil temp 20-30 deg F. Thermometer is in oil return tank.
Running Mobil 1 20-50 MC oil in the engine, two up outside temps in the 70's it will run between 200 - 230/240 depending on highway or city.
In the owners manual it says to check the oil when the oil is at oprating temp of 230 deg F, so in my opinion that is the normal operating temp of the oil. If you are stuck in traffic, high 90's oil temp will go to 250 easily.
Running Mobil 1 20-50 MC oil in the engine, two up outside temps in the 70's it will run between 200 - 230/240 depending on highway or city.
In the owners manual it says to check the oil when the oil is at oprating temp of 230 deg F, so in my opinion that is the normal operating temp of the oil. If you are stuck in traffic, high 90's oil temp will go to 250 easily.
Remember back in the 60', 70's, when the Harleys used by city cops spent much of the day sitting and idling while they checked parking violations and such. No coolers, no synthethics. Wonder what one of those motors looked like after a few years of that?
I can tell you one thing, I have a '96 ex cop bike that was rode hard and hung up wet, and the biggest problem I have had with it motorwise has been minor oil drips. The rest of the bike has had some broken items, due to the nature of how it was used by various riders. But have been easy and cheap to repair.It still runs and ride pretty well, and I get anywhere between 42-46 mpg. It's no beauty contest winner, so I don't get all upset when it's dirty or gets knicked by a rock. These bikes are tougher then most people think.,,
Optimum oil temperature;
Harley Davidson Answers: For what it is worth!
"The optimum operating oil temperature for both XL and Twin Cam. Ideally the bulk oil(the oil in the tank) should be between 220F and 250F during normal operation. This ensures that any water vapor that gets into the oil from combustion process is vaporized and can be purged from the system through the breathers. For elevated ambient temperatures, the bulk oil can safely operate at temperaturs up to 300F during extended idling or high speed interstate cruising. Harley-Davidson's motor oil has been specially formulated with enhanced anti-oxidation package to minimize oil oxidation concerns above 250F. The reserve alkalinity of the oil formulation has also been boosted to minimize any acid formation that could accur with elevated oil temperatures".
Sound like stuff we might look for in a MC oil?
Harley Davidson Answers: For what it is worth!
"The optimum operating oil temperature for both XL and Twin Cam. Ideally the bulk oil(the oil in the tank) should be between 220F and 250F during normal operation. This ensures that any water vapor that gets into the oil from combustion process is vaporized and can be purged from the system through the breathers. For elevated ambient temperatures, the bulk oil can safely operate at temperaturs up to 300F during extended idling or high speed interstate cruising. Harley-Davidson's motor oil has been specially formulated with enhanced anti-oxidation package to minimize oil oxidation concerns above 250F. The reserve alkalinity of the oil formulation has also been boosted to minimize any acid formation that could accur with elevated oil temperatures".
Sound like stuff we might look for in a MC oil?
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Originally Posted By: BillyTheKid
I think I need to get an oil temp gauge on my bike after reading this. I know the oil is very hot and cooking in my set-up.
Don't..... You'll just scare yourself!
I think I need to get an oil temp gauge on my bike after reading this. I know the oil is very hot and cooking in my set-up.
Don't..... You'll just scare yourself!
My 09 Ultra. This oil was tortured by running at extreme heat for extended periods of time riding 2-up. 270*+ sometimes exceding 300*.
Here in Phoenix it gets 115* and I ride year around.
Here in Phoenix it gets 115* and I ride year around.
Sometime back in the 90's I managed to destroy fresh Castrol 20-50 GTX while riding my air-cooled GPz across the Mojave desert. It was July and temps were around 115, with occasional hot spots that must have been 5+ degrees hotter. (Just when I thought I'd acclimated to the blast furnace conditions the air temp would jump significantly, usually as the road dove down onto a riverbed or other low spot.) The bike endured these extreme temps for only about 3 hours while traveling from Mojave to Baker (despite stopping at every opportunity to chug water, the rider was about to keel over!), but that was enough to burn the oil to a black goop.
Originally Posted By: Geonerd
Sometime back in the 90's I managed to destroy fresh Castrol 20-50 GTX while riding my air-cooled GPz across the Mojave desert. It was July and temps were around 115, with occasional hot spots that must have been 5+ degrees hotter. (Just when I thought I'd acclimated to the blast furnace conditions the air temp would jump significantly, usually as the road dove down onto a riverbed or other low spot.) The bike endured these extreme temps for only about 3 hours while traveling from Mojave to Baker (despite stopping at every opportunity to chug water, the rider was about to keel over!), but that was enough to burn the oil to a black goop.
Mine was tortured like that for 5000+ and tested good.
Sometime back in the 90's I managed to destroy fresh Castrol 20-50 GTX while riding my air-cooled GPz across the Mojave desert. It was July and temps were around 115, with occasional hot spots that must have been 5+ degrees hotter. (Just when I thought I'd acclimated to the blast furnace conditions the air temp would jump significantly, usually as the road dove down onto a riverbed or other low spot.) The bike endured these extreme temps for only about 3 hours while traveling from Mojave to Baker (despite stopping at every opportunity to chug water, the rider was about to keel over!), but that was enough to burn the oil to a black goop.
Mine was tortured like that for 5000+ and tested good.
Originally Posted By: kballowe
I just wonder..... Does anyone know if the average motor oil flash point has risen in say, the last ten years or so?
Yes because the base oils have evolved ever since the 70s and 80s.
Originally Posted By: kballowe
In my mind, the flash point is an indication of how the oil will perform and how long it will stay in grade - in elevated temperatures. At the very least, many air-cooled motorcycle owners will seriously consider a higher flash point when selecting a particular oil.
Or is it just me?
1. I always understood that Flash point is just an inherent value associated with the total oil formulation balance (a results of the ingredients mix). Is this not correct ?
2.However definitely the higher flash point is not so important as it is to use an oil that stays within close range of the original fresh oil flash point range during the full life of the oil.
If this is proven, it is proof that the oil is an Excellent formulation for the application(car, bike, truck, etc).
I just wonder..... Does anyone know if the average motor oil flash point has risen in say, the last ten years or so?
Yes because the base oils have evolved ever since the 70s and 80s.
Originally Posted By: kballowe
In my mind, the flash point is an indication of how the oil will perform and how long it will stay in grade - in elevated temperatures. At the very least, many air-cooled motorcycle owners will seriously consider a higher flash point when selecting a particular oil.
Or is it just me?
1. I always understood that Flash point is just an inherent value associated with the total oil formulation balance (a results of the ingredients mix). Is this not correct ?
2.However definitely the higher flash point is not so important as it is to use an oil that stays within close range of the original fresh oil flash point range during the full life of the oil.
If this is proven, it is proof that the oil is an Excellent formulation for the application(car, bike, truck, etc).
I have an oil temp dip stick on my Honda Xr 400 off-road bike and see around 200-225*.
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