Oil Question

[chapindad]

I know this is over done on most auto sites and probably in the past on here also.  But usually the debate is over oil brands.  I would like to know technically what all the numbers mean on the oil can and why they are important.  For example, I know the first number is the weight of the oil but why is that important and why do I nee to know it. 

I know I could probably google it but there are some very smart guys on here and I would rather hear from experience.

Thanks

[mikeholzer]

Using 5W-30 as an example, the number 5 represents the true weight of the oil. The letter W indicates that it is a winter suitable oil. Multi weight oils have viscosity improvers in them which increase the oil's "thickness" once it heats up. In this case, 30 represents the "warm" weight of the oil.

If you search for it, you will find a variety of threads on the subject of oil. Everybody likes something a little bit different, and there are a wide variety of opinions available. The general agreement, however, is that the Yamaha callout for 10W-40 is pretty much spot on. Heavier weight oils may cause starting issues, and lighter weight oils don't offer adequate protection. Some people have experienced clutch slipping issues using some synthetics, others have not. I personally have tried a variety of oils from Castrol Dino to Golden Spectro; the primary difference that I have noticed is the weight of my wallet in the end. I'm currently using Shell Rotella 5W-40 synthetic, which is available at my local Walmart for around $20 per gallon.

Finally, most members here will advise replacing the OE filter with the spin-on filter adaptor available from Randy at RPM (www.rpmracingca.com). It's fairly inexpensive, you can use a variety of automotive spin-on filters with it, and it makes LOF sevice 100% easier.

[Arnie]

Sorry Mike, but there is and has been NO agreement on this or any other FJ forum I've seen about what oil type, weight, or brand to use. 
Nor has there been any general advise to change to a spin-on filter although many have, more have not.
With the case of oil and motorcycles, including FJ's, the only constant is DIS-agreement.

Arnie

Using 5W-30 as an example, the number 5 represents the true weight of the oil. The letter W indicates that it is a winter suitable oil. Multi weight oils have viscosity improvers in them which increase the oil's "thickness" once it heats up. In this case, 30 represents the "warm" weight of the oil.

If you search for it, you will find a variety of threads on the subject of oil. Everybody likes something a little bit different, and there are a wide variety of opinions available. The general agreement, however, is that the Yamaha callout for 10W-40 is pretty much spot on. Heavier weight oils may cause starting issues, and lighter weight oils don't offer adequate protection. Some people have experienced clutch slipping issues using some synthetics, others have not. I personally have tried a variety of oils from Castrol Dino to Golden Spectro; the primary difference that I have noticed is the weight of my wallet in the end. I'm currently using Shell Rotella 5W-40 synthetic, which is available at my local Walmart for around $20 per gallon.

Finally, most members here will advise replacing the OE filter with the spin-on filter adaptor available from Randy at RPM (www.rpmracingca.com). It's fairly inexpensive, you can use a variety of automotive spin-on filters with it, and it makes LOF sevice 100% easier.

[E Double]

Here (http://motorcycleinfo.calsci.com/Oils1.html) is an excellent paper about motor oil.  If you are really interested in everything about oil Bob is the Oil Guy (http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=cfrm)is an excellent resource with a forum that has a ton of oil geeks on it, including myself 

[mikeholzer]

My apologies, Arnie. I didn't mean to say that there was any general agreement on any facet of the oil/chain/filter/etc. arguments. I had only meant that there does seem to be some "agreement" on the spin-on filter modification being a fairly good thing. At no point did I suggest that there was any sort of agreement as to what oil type, weight, or brand to use, other than that many here agree that the 10W-40 works.

Oh hell! Maybe I did make it sound as though there was a greater agreement than there is. My sincerest apologies to you, Arnie, Mr. Chapindad (sorry that I didn't catch your name, sir), and anyone I may have misled.

I mean this sincerely; there is no sarcasm involved here. Oil is good, use what you like. Everybody has an opinion on this subject, and for the most part none of them are wrong.

[carsick]

first number is the weight of the oil but why is that important and why do I need to know it?

Returning to the original post question,
too low a viscosity (too thin) = metal to metal contact while engine is rotating. Severe wear leading to dead engine. Low oil pressure if clearances are large. Noisy engine and trans. Heat exacerbates these conditions, and an air cooled motor can get some hot!

Too high a viscosity (too thick) = lower fuel efficiency, lower power, starter clutch engagement troubles, difficult shifting, possible wear on startup due to oil starvation caused by restriction (more of a cold weather thing).

Multi viscosity oils have made it much easier to find the sweet spot between the two extremes. Change it regularly and keep it full, far and away the most important aspect.

[chapindad]

Here (http://motorcycleinfo.calsci.com/Oils1.html) is an excellent paper about motor oil.  If you are really interested in everything about oil Bob is the Oil Guy (http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=cfrm)is an excellent resource with a forum that has a ton of oil geeks on it, including myself 

Sorry for the long delay.  WHAT A GREAT ARTICLE!  I really enjoyed it and feel a little cheated and ashamed that I did not know that information in 25 years of working on my own cars.  Now I understand why all the oil wars on threads happen, it's like understanding the joke for the first time. 

[E Double]

Glad you liked it.  The author definitely knows his stuff.  I've had very positive results with Amsoil's fluids, which I use in my bike (10-40, with plenty of life left at 6K miles oil change interval), both our car and our truck (from engine oil, trans to diff), even in my lawnmower and snowblower.  I'm not saying that Amsoil is the best stuff out there for everybody, but I definitely think using a good synthetic in a bike (especially air-cooled ones like our FJs) is the way to go.  And since I like paid for, I'll take spending a bit more for fluids so I can run something until the wheels fall off.  My last truck was an '89 f150, and when I gave it to my cousin to use as a farm truck this fall it had 350K miles on it.  Looked like hell, but it ran like a top, and got 20mpg when I drove it the 470 miles to his farm.  Ran synthetic in it from front to back for the last 200K miles.