newbie oil??

Had the same thing after my last service. Blew HEAPS of smoke and i kacked myself thinkin my bike was going to blow up but it turned out the mechanic had dropped a little oil into the headers.

 

No no no no no no no no.

Viscosity / weight of an oil.
Viscosity is the flow ability of oil. People talk about the weight of oil but technically they are taking about the viscosity. Oil that has a viscosity rating of say 25W/60 would be referred to as a heavy oil or high viscosity oil. Take that to the other end of the scale with a 5W/30 and you have a light or low viscosity oil

A common misconception with viscosity is the way in which the rating is determined. For some strange reason people seem to think that when oil is at ambient temperature it is rated at the lower spec IE 5W and thickens as it gets to operating temperatures. To a 30 when its hot.
But if you think about that logically as a liquid heats up it has thin out.
To put this into perspective if you look at the Typical Specifications of engine oil this will always show the Viscosity at 40c and at 100c for instance a 20W/50 at 40c will be around 189 centistokes (cSt) at 100c 19 cSt this is the rate at which the oil is able to flow.
CSt or centistokes is the measure used in determining the viscosity of oil. Without trying to confuse you there is also a cP or centipoise witch is where the W of a classification comes in to play at below 0c.
For instance the 20W/50 @ -10c has a viscosity of 4,402 cP (that’s thick).

As to the general rule of knowing what viscosity to use, it is safe to say the hotter the temperature the higher the viscosity. So in Japan running a 0W or 5W30 is fine when you take into consideration that the ambient temperatures are low some times freezing. Put that into Australian conditions and by the time you get up to operating temperature you may as well be running water in your sump.

 

HOLY CRAP SOMEONE WHO KNOWS ABOUT OIL! HALLAFRICKENLOUYAH!

 

What he said.
I must have picked up some wrong info there <!-- s --><img src="{SMILIES_PATH}/icon_redface.gif" alt="" title="Embarassed" /><!-- s -->

 

i think we should make this one a sticky

 

Aahhh where did you pull that from? Last I checked a centipoise was just a measure of absolute viscosity and is used to calculate centistokes.

That is just as misleading as the last statement! If you are read a label xxW-xx it is describing an SAE standard J300. According to which the viscosity is measured at 100 degrees C for the last number and at varying temperatures for the first as shown in this table.
<!-- m --><a class="postlink" href="http://www.infineum.com/information/api-viscosity-2004.html">http://www.infineum.com/information/api ... -2004.html</a><!-- m -->
At which point depending on the viscosity, fall into different oil categories specified in the same table. The higher the number of the oil grade the more viscose it is @ 100 degrees C. Note this doesn’t apply to the W rating. Confused yet?

So lets do some interpreting of the SAE J300 standard.
Take a SAE10w-50 oil. This means that at -25 degrees C it will have a minimum Kinematic Viscosity of 4.1 cSt and at 100 degrees it will be between 16.3 and 21.9 cSt. It can be effectively used at -25 degrees C and as long as you bike isn’t overheating will provide more viscosity than stated in the spec. of SAE20W-40SE as seen below.
<!-- m --><a class="postlink" href="http://www.my-x15.net/fzr250/FZR250specs.pdf">http://www.my-x15.net/fzr250/FZR250specs.pdf</a><!-- m -->

I have no idea why they had to make it so complicated.

 

because they are engineers <!-- s:alcoholic: --><img src="{SMILIES_PATH}/icon_all_coholic.gif" alt=":alcoholic:" title="Alcoholic" /><!-- s:alcoholic: -->

 

oil level

regardless of oil temperature the oil should be level with or above the indicator mark. the indicator mark is a little line on the engine just to the right of the oil viewing glass. when you turn the engine off give the oil minute to settle, the oil has to seep down from the engine. if the oil level seems to high when the engine is hot it can be caused by bubbles in the oil from all the churning around, proper motorcycle engine oil has antifrothing agents in it because bike engine oil has to lubricate the clutch and gear box aswell. oh and im sure you know this but the bike has to be level, not on its stand to take a proper reading of oil level.

 

It's only confusing because so many people explain it badly


The first thing that always confused me was just the definition of viscosity - I got it around the wrong way. So for anyone else as dumb as me: The higher the viscosity, the more resistant the fluid is to flowing. ie the lower the viscosity number, the easier it flows. The higher the viscosity, the stickier it is, and the worse it flows.

The next thing that always confused me was that i thought the two number were related to each other (ie that 10w50 meant a viscosity of 10-50 in the specified temp range). But that's wrong!

The first number should not be thought of as viscosity (because it's not!). Instead, it's a reference in the table that ciaran linked to above. To find the related viscosity, you have to look it up in the table.

The second number, however, is a viscosity rating... as ciaran said, it's the viscosity at 100c.


Two quick examples:
5W30
Looking up 5W in the table gives a viscosity of 6600 at -30 degrees celcius. 6600 = HIGH (ie it's very viscous and hence flows very slowly)
and the second number (30) indicates a viscosity of 30 at 100 degrees celcius (ie it's not very viscous, and will flow quite easily).

Another example
20W30
20W indicates a viscosity of 9500 at -15 degrees celcius [see ciaran's table]. Compare this to 5W and see how much more viscous this is, especially given the temperature difference! This oil will not flow well in negative temperatures.
again, the 30 indicates viscosity of 30 at 100 degrees celcius, so despite the difference in the -ve temperature range, when your engines running hot this thing provides exactly the same protection as the 5W stuff did.


Hope that clears things up a bit, heh.



The other thing to remember, though, is that the more viscous the oil it is, the harder it is for your engine to pump it. That means you'll lose power trying to pump the thicker oil around.
So if you're after more power, you'd run a less viscous / thinner oil... although this, of course, provides less protection to the engine.

 

Bringing this discussion back to earth, what are the benefits that you guys find when using Motul 5100 over the other leading brand?

 

The last statement is true- about less viscosity for more power. BUT oil I'm using produces more power even in a 20w60 variant than 15w40 Mobil.