question about oil.............viscosity

[tlg1100]

25 yrs ago a suzuki dealership told me they use castrol 20-50 in most bikes , maybe not nowadays, so thats what I have been using ever since and the p.o.s still runs after all these years never had the motor opened up for any thing,better oil now so might switch.

[Mysuzyq]

as i open this can of worms, i was wondering if anyone has tried using 20w50 in there GS's. i have an 81 1100e currently without an oil cooler. so what i want to know is would 20w50 help my engine ru not as hot in the summer?

An oil cooler would benefit you the most IMHO, to lower temps....you should also see a noticeable difference in temps by switching to synthetic oil, even with 10W-40. I ran a 1:3 blend of Amsoil 0W-40 synth and Castrol 10W-40 (either regular GTX, or their GP motorcycle oil), and it did bring down temps noticeably, so much so that I would not run straight synthetic up here in fall/winter, due to difficulty in getting the oil to operating temperature. Reading on BITOG (Bob Is The Oil Guy) forum and elsewhere, the reason seems to be that because synthetic oil has a uniform structure at the molecular level,unlike refined dino oil, it is better able to transfer heat via convection.....it apparently also has a lower coefficient of friction than conventional oil. If you do spring for a full synthetic fill, do let us know the results (do you have a temp gauge?).
Here is an interesting, (though long) article on the subject, if you are bored.

http://mr2.com/TEXT/synth_oil.txt

FWIW, I now run full Castrol GP 10W-40 conventional motorcycle oil (only slightly more money than regular GTX)...my clutch seems happiest with it, and it's easier to get the oil to temps in colder weather (I have an oil cooler).

Tony.

EDIT:
From the article I linked...

...[The remarkable ability of synthetic oils to reduce internal operating
temperatures is far too important to ignore, since high operating
temperatures contribute directly to premature failure of mechanical
components and gaskets and seals. Coolant (i.e. water/antifreeze) cools
only the upper regions of an engine. The task of cooling the crankshaft,
main and connecting rod bearings, the timing gear and chain, the
camshaft and its bearings, and numerous other components must borne
entirely by the oil. There are three identifiable reasons why
synthetics do a better job of cooling an engine: (1) Because of both the
oil's lubricity (slipperiness) and it's stable viscosity, less
friction-- and thus less heat-- is generated in the first place; (2) The
molecular structure of the oil itself is designed to more efficiently
transfer heat, even compared against the thermal conductivity properties
(ability to absorb and dissipate heat) of an identical-viscosity
petroleum oil; and (3) As mentioned in the preceding paragraph, the more
rapid oil flow of these lower-viscosity synthetics contributes
significantly to the efficient transfer and dissipation of heat.
*Because of all these factors, oil-temperature decreases of from 20F to
50F are quite common with the use of synthetic oil*. One might even say
that the heat-reduction properties of synthetics are synergistic...by
helping to reduce its own temperature, the synthetic oil is
simultaneously enhancing the lubricant's overall performance
characteristics....]

[Nessism]

I've hung out on the Bob is the oil Guy forum long enough to know that synthetic oil does not reduce wear under normal usage, nor will it result in lower operating temperatures. Synthetic oil will last longer, flow better when cold, and not flash off as easily in high temps which allows it to protect better in high heat. Those are it's main positive characteristics. If you don't believe me go to BITOG and look at the oil analysis threads. If anything, dino oils tend to show less wear particles in the oil than synthetic. The numbers don't lie.

[Mysuzyq]

I won't argue about it, merely state that in my usage, it did bring down temps....it's why I asked the poster to report his findings too, either way.

Tony.

[TheCafeKid]

I've used both full synthetic (royal purple) and standard auto grade oil as well as rotella 15-40. In all cases I've never noticed an operating temp change and i have a guage. What I HAVE noticed is that the oil breaks down either faster or slower depending on the oil. The royal purple broke down just as quick as the rotella. So that was the one and only time I spent 30+ bucks on oil for my Bike. The other thing I noticed is that my clutch didn't throw a fit over full synthetic contrary to popular opinion/belief. Now the standard grade car (not EC) Castrol I used seemed to break down the fastest. (I'm grading this using the two tells I use to tell me when it's time to change my oil besides mileage and those are top end racket and smoothness of shifting, I don't necessarily change my oil every 2-2500 miles, but rather when the bike tells me it wants it changed. If I've run it hard in the summer, rowing thru gears at a rally and running in high rev ranges for long periods of time I might change it 1500-1700 miles in but never longer than 2500 miles) Rotella I've found seems to handle the temps (it gets hot and humid in the Ohio River vally in July) and punishment every bit as well as high dollar synthetic oils, and is easier on my wallet. Castrol breaks down too quick, and I'd assume the same for most car grade oils. Motorcycle oil is simply rediculous to me and I'm not gonna pay for it when other oils are easier to obtain and cheaper and do just as well a job.
Having become aquainted intimately with diesel motors growing up, and knowing the pressure and strains diesel oil is confronted with regularly and how important it is to maintaining a diesel motor for long periods of time, i don't think there is a more adequate product on the market for our GS needs. Just my .02.

[rustybronco]

What I HAVE noticed is that the oil breaks down either faster or slower depending on the oil. The royal purple broke down just as quick as the rotella. So that was the one and only time I spent 30+ bucks on oil for my Bike. The other thing I noticed is that my clutch didn't throw a fit over full synthetic contrary to popular opinion/belief. Now the standard grade car (not EC) Castrol I used seemed to break down the fastest. (I'm grading this using the two tells I use to tell me when it's time to change my oil besides mileage and those are top end racket and smoothness of shifting, I don't necessarily change my oil every 2-2500 miles, but rather when the bike tells me it wants it changed.

The one time I used amsoil... http://www.thegsresources.com/_forum...3&postcount=18 . I'll let you know if it does the same on a different bike. also, FWIW, royal purple is a hydrocracked base stock oil just like most any other "synthetic oil" out there; unlike amsoil, motul or redline.

***I don't sell or have any affiliation with the stuff, I'm just saying what it did when I used it.***

[Mysuzyq]

The motorcycle specific synthetics are supposedly wet clutch safe, so clutches do not 'throw a fit' whilst using them, if the clutch is in good working order to begin with. In my case, new springs were needed....the entire clutch assembly is still the original one from 1982.
I'll second Rusty's finding about the shifting smoothness however...with the Amsoil (blend), it remained smooth right up to the mileage dictated next change.

Tony.

DISCLAIMER: To each his own....use what you will, believe what you will...chances are, any oil you choose today (not EC) will be better than what was used in '82, as lubricant technology has come a long way since (though Ed's point about reduction of zinc levels is well taken).

[Nessism]

The newest blend of Rotella is certified MA, which means it's safe for wet clutches. No more excuses for those that need a certification to give them piece of mind.

http://www.shell.com/home/Framework?siteId=rotella-en&FC2=/rotella-en/html/iwgen/leftnavs/zzz_lhn2_0_0.html&FC3=/rotella-en/html/iwgen/products/products_home.html

[Shin-Ken 1074]

As Ed has stated to ensure you don't have an issue using oil in a wet clutch system use MA certified oil. There are different types of MA rated oil so you'll just have to check which one suits your bike. All genuine MA rated engine oil have the Type MA details listed in a rectangle label on the oil container. For my GS1100 and GSX1100 I use the 15W50 Dino Juice, the specifications listed in the rectangle label are:

JASO T 903-98 (D)
Type MA, API: SG,
Honda Spec

Don't worry about the Honda Spec, its for all Japanese engines. As for the oil temp I don't worry about it, what I do ensure is that I change the oil and filter every 3000km / 1800 miles. With over 400,000 km of trouble free engine wear on the GS1100G I use that data as my measure for oil use and maintenance programming. This oil is priced the same as regular Dino oil here so the costing is not a factor. Cheers.