Oil Analysis

[NBA336]

You all might have seen this before, but a friend sent this to me and it appeared to be one of the best descriptions of required oil, analysis and how the whole thing comes together when talking about oil, IMHO

http://www.motorcycleanchor.com/motorcycle/how_to/mc_oil.html

[jackpine savage]

It looks like there is plenty of good information there.

I wonder though about this "problem" of using car oil in motorcyles. The distinction between car engines and motorcycle engines is becoming very small. Here I'm talking about the ST engine for example and not a high reving air-cooled motor. They both run at about the same temperature so no difference there. Performance car engines are now reving to 6K RPM or more vs 8K for the ST so there is little difference there. The wet clutch is another matter and of course you don't want the moly additives to cause slipping but if I'm not mistaken, that's easy to avoid.

So why this concern about running only motorcycle oil? Is this just a holdover from the days of air-cooled bike engines?
David

[dave1315]

Consider the rpm range of most performance bikes as well. It's quite a bit wider than the majority of cars out there.

[Horst]

... 1) Common tranny / engine ... 2) Wet clutch ... no car has this. :eek:

[crazykz]

... 1) Common tranny / engine ... 2) Wet clutch ... no car has this. :eek:

I think some diesel engines do this don't they? That's one reason the Shell Rotella is a recommendation right?

Curt

[hippo888]

The new "energy conserving" auto oils are not recommended for motorcycles. For example, if you take a look at Mobil 1 synthetic for motorcycles, it does not have the energy conserving star logo. I don't remember what Sx grade the energy conserving oil is, maybe SJ/SL?

The new energy conserving auto oils are made to increase gas mileage through friction reduction. They contain lots and lots of additives that won't survive in a motorcycle unit-construction engine. BMW in particular states that energy conserving oils are not specified for their motorcycle engines.

[Horst]

... that's all. No common tranny, separate. That's what makes m/c different and that's why you can't pour just any car oil into our cases.

Most of the studies quoted confirm that the tranny gears 'chew up' oil molecules ... that's why our oil does not last as long. :rolleyes:

[NormanPCN]

The new "energy conserving" auto oils are not recommended for motorcycles. For example, if you take a look at Mobil 1 synthetic for motorcycles, it does not have the energy conserving star logo. I don't remember what Sx grade the energy conserving oil is, maybe SJ/SL?


The Energy conserving certification is separate from the Sx certification. So an Sx oil may or may not also meet the energy conserving spec.

[NormanPCN]

... that's all. No common tranny, separate. That's what makes m/c different and that's why you can't pour just any car oil into our cases.

Most of the studies quoted confirm that the tranny gears 'chew up' oil molecules ... that's why our oil does not last as long. :rolleyes:

I think it is the viscostiy modifiers that are the really vulnerable items. I have never seen really frequent change specs for transmissions/transfer case/differential. Applications that use gear oil. Besides having different additive packages gear oils do not have the viscosity modifiers of engine oil. Viscosity modifiers are hyper long molecules that curl up when cold and unravel when hot. This is how you get variable viscosity in engine oils. These molecules are especially vunerable to shear. Actual oil does significantly better. So a 15-50 oil is basically a 15 weight oil that has additives to keep the 15 weight oil from getting thinner than a 50 weight oil at temp (212F I believe). In other words, no thicker than a pure 15 weight oil at freezing and no thicker than a pure 50 weight oil at boiling.

[Horst]

Hi Norman ... you're right about the many additives ... they are necessary to enable a 5W for example, to behave like a 50W or whatever. 15W50 requires fewer additives / friction modifiers, so should be safer for our bikes. :biker:

[jackpine savage]

Consider the rpm range of most performance bikes as well. It's quite a bit wider than the majority of cars out there.


I thought we were talking ST1300 here. I'll restate my point, there's not much difference anymore.
David

[jackpine savage]

... that's all. No common tranny, separate. That's what makes m/c different and that's why you can't pour just any car oil into our cases.

Most of the studies quoted confirm that the tranny gears 'chew up' oil molecules ... that's why our oil does not last as long. :rolleyes:

I can't believe that tranny gears can be harder on lubricants than the severe torque, heat and pressures placed on rod and main bearings in the engine. Transmission lubrication is a relatively easy job for any oil. I think the marketing people have developed this need for "special oil" at of course extra expense.
David

[NormanPCN]

I can't believe that tranny gears can be harder on lubricants than the severe torque, heat and pressures placed on rod and main bearings in the engine. Transmission lubrication is a relatively easy job for any oil. I think the marketing people have developed this need for "special oil" at of course extra expense.
David

Main bearings are not a metal to metal contact situation. The oil pressure floats the crank on the bearing. Of course there is metal to metal contact but it is a different mechanism of lubrication that things like the cam lobes actuating the valve or the piston and rings touching the cylinder wall. In the later the oil is lubricating via a film of slippery stuff. The former uses the slippery stuff principle but oil pressure is also used to provide a hydraulic effect.

[yoitsmatt!]

I agree that the difference in car oils and bike oils is much less than in the past, granted cars dont have the trans and engine using the same oil but:
cars now have overhead cams and followers(metal to metal contact)
gear driven oil pumps, gear and chain driven timing assemblys, counterbalances, mostly gear driven, oil pressure actuated cam timing devices and oil pressure timing belt tensioners, so when oil is squeezed excessilely it tends to break down or "sheer" a good synthetic tends to "sheer" less or at least thats what ive read and then theres the nasty by products of internal combustion to worry about, no matter how good an oil you use even it it stands up to the heat and forces the transmission give it , theres always going to be carbon and blowby trying to ruin it, so i guess my point is this, as long as it doesnt make the clutch slip the engine is going to ruin the oil before the trans ever has a chance to break it down and you you should take that into consideration before anyone talks you into running any oil for some ridiculously long amout of time! 15K! ha!!! most engines would be out of oil before they go that far!