Oil Type

I just went to buy a few liters of Mobil 1 15W50 for my XR650L. Every store in town has replaced it with Mobil 1 5W50. Has anyone had good luck using this weight of oil in their bikes?

Should theoretically be better- the difference is the first number which is an indicator of how thick the oil gets at lower temperatures (like in BC in the winter). The 5 weight won't thicken up as much as the 15 when cold, so you'll get better lubrication at startup. At operating temp you'll still have a 50 weight regardless of which one you use. Mobil know thier business; I'd use it without worry.

Best,

Robert

Are you using the automotive mobil or the motorcycle oil? There is a diff. Not sure on the auto mobil but make sure it does'nt have the energy conserving label or your clutch wont like it.

I just went to buy a few liters of Mobil 1 15W50 for my XR650L. Every store in town has replaced it with Mobil 1 5W50. Has anyone had good luck using this weight of oil in their bikes?

Keep in mind the greater the weight range (ie: 5w-50 vs 20w-50, etc.) the more Viscosity Index Improvers (VII's) that are present. VII's are polymers added to the base stock (the natural/original weight of the oil) to keep it thick/thin at certain temperatures.

When cold, VII's coil up, and can flow with the base stock viscosity easily. When they heat up, they stretch out, and create a thicker oil to compensate for heat-related thinning.

OK, so all well and good, until the oil is put in a bike. Apparently, the transmission gears tend to mutilate these VII's over time, and not a whole lot of runtime, either, which reduces the resistance to flow at higher temperatures. The net effect is that the original 5w-50 may be like a 5w-30 or 5w-20 after 1500 or less miles.

It is best to buy a oil with a weight range closest to your intended use/climate since there are less VII's present.

This is a *very* controversial subject, but when you get the time (there's a lot of info here) read this:

http://www.nightrider.com/biketech/oiltest1.htm

http://motorcycleinfo.calsci.com/Consumables.html#Oil

http://motorcycleinfo.calsci.com/Oils1.html

Keep in mind the greater the weight range (ie: 5w-50 vs 20w-50, etc.) the more Viscosity Index Improvers (VII's) that are present. VII's are polymers added to the base stock (the natural/original weight of the oil) to keep it thick/thin at certain temperatures.

Not generally true for polyalphaolephin (PAO) -based synthetic oils which have naturally wide viscosity indices. Used to do a lot of work with Roush Performance; one of the engine calibrators there told me that "Mobil 1 is the best widely available oil you can buy." I wouldn't use something like Castrol Syntec which isn't actually synthetic, but the M1 is a no-brainer.

Not generally true for polyalphaolephin (PAO) -based synthetic oils which have naturally wide viscosity indices. Used to do a lot of work with Roush Performance; one of the engine calibrators there told me that "Mobil 1 is the best widely available oil you can buy." I wouldn't use something like Castrol Syntec which isn't actually synthetic, but the M1 is a no-brainer.

Good point, but readers should keep in mind that it is very applicable to the majority of oil on the shelf, both dino and synth.

I run MX4T (M1 for bikes) in my YZF600 for the reason you pointed out, plus MX4T is good for an extended change interval (time purposes, not high-mileage purposes).

My XR's get Rotella 15w-40 or Castrol 20w-50.

I ran Mobil 1 15-50 in my XR350R (7 years) and my Transalp (50,000 miles). Never touched the clutch on either and while the XR used some oil on start up, it never was a real problem.

I run Mobil 1 5-40 in the winter in three of my current vehicles: XR200 and 600, and my wife's WRX. The 600 doesn't clatter when cold (20 degrees) with the 5-40.

As an aside, my commutermobile 1993 Geo Metro (1L 3-popper) uses a quart of oil every 2 gallons, an 8:1 mix. It smokes like a chainsaw but doesn't foul plugs and still gets 55mpg.

"O"

After reading the articles suggested by phuzz it seems to me that motorcycle oils are just a waste of money and a hole bunch of marketing hype. I think that the automotive Mobil 1 5W 50 will work just fine and most likely better than a lot of other oils.

I've heard good stuff.

Phuzz once again makes some very good points!

Mobil1 is a very, very good oil the only word of caution is make sure whatever oil you use does not contain a "moly" additive (wreaks havoc on the wet clutch)

I have been very impressed with the shell rotella products.

I believe that as long as you use the correct weight for your climate and change oil regularly, all will live fine.

I must admit though I have been using the Belray Thumper oil in a 20/50 weight with good results. It is a very thick oil that holds its viscosity well over the miles, but would not reccomend this weight for BC probably a 5/20 for winter time.

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