Good idea Josh.  Having read all this I don't have a problem with using 15W-40 but I wouldn't use 5W-40.  Our engine needs thinner oil like a hole in the head.

Quote from: bill14224 on March 10, 2009, 06:05:14 AM
Good idea Josh.  Having read all this I don't have a problem with using 15W-40 but I wouldn't use 5W-40.  Our engine needs thinner oil like a hole in the head.

I'm with you there.

Quote from: galahs on March 10, 2009, 04:10:17 AM
Castrol sells a 5W-40 synthetic motorcycle oil here and is recommended for all 4 stroke bikes,

Personally I would be worried 5W is too light weight, but there is often alot of un-founded fear regarding these types of issues. Its probably fione.


Anyway, check out the Wicki http://wiki.gstwins.com/index.php?n=Maintenance.EngineOil

Castrol also has Delo 400 which is there mixed fleet oil and the closest we can get to the Shell Rotella in Aus. It's a 15W-40 which should be fine. They also have Delo Gold and Delo Silver which aren't synthetic but meets the requirements of the GS, also 15W-40. I'm going to be trying one of these when my current oil runs out.

Quote from: bill14224 on March 09, 2009, 06:40:50 PM
If you thought you knew the answer, why did you ask the question?  And why the smarmy response?

I'm not willing to go by speculation and online testimonials of strangers.

I also know that the GS 500 is air-cooled, and has looser tolerances than liquid-cooled engines.  That, and the fact it has 2 valves per cylinder is why it puts out 45 hp instead of 60.  The GS will burn more oil if the oil is thinner.  Motorcycle engines are not all the same.  I will use what the book says and change it when it's starting to turn color.  I buy 10W-40 SM or SL rated oil at the auto parts store for 2 bucks a quart.  Not a big investment to warrant screwing around with.

You can use canola oil in your bike if you want, but don't expect me to.

I thought I knew the anwser, but that's why I asked the question. And as for the  smarmy response, I'm sorry I got you all worked up. I'm from the school no question is a dumb question! Bottom line I'm sorry for the oil post that everyone gets pissed off at. Happy riding

I didn't get pissed off, I just don't think it's a good idea to run thinner than recommended oils in air-cooled bikes with their looser tolerances.  Whether they're synthetic or not isn't relevant.  I just wouldn't want to see anyone ruin their engine unnecessarily.  I do know that you can run recommended 10W-40, or the 15W-40 "dino oils" that others have recommended without ruining your engine, and it's no more expensive than what you're recommending.  There are less expensive oils than the outrageously expensive oils they sell at the dealerships that meet all the requirements of our bikes, and it's in writing, not heresay.

I would be more willing to listen to testimonials about running lighter oils like this in air-cooled bikes if those who did so put a lot of miles on their bikes.  Problem is, few do, and many people make stuff up.  I'm not accusing you of making anything up, but my point is why risk it when you can get the right product in writing for the same price?

If you're willing to run the risk, go ahead and put 50,000 miles on your GS with Rotella T, keep track of your oil usage and any mechanical problems you might run into, and get back to us.  Then I'd be all ears.

why not just use 10w40 like the dipstick says ?

i really don't get why folks go around this bush 100 times on every forum. what is so mysterious about oil that perplexes folks into wanting to 'try' 4-5 different brands, viscosities, and varieties ?

sure, i tried synthetic this last time, but now i'm thinking they were out of the cheap 10w40 i usually buy. can't remember why i did now. oh well. back to castrol (or whatever cheap crap is on the shelf) for the next change.

:|

Would it only count if that person was on this forum? Seriously there are many tribologists on bobistheoilguy.com that can attest that diesel 5w-40 is no thinner under normal engine conditions than 15w-40. Only under severely high mileages like over 10,000 miles and temperatures does rotella remotely break down, I mean it's made for diesel engines, which shear wise and pressure wise stress is much worse than the GS500 places on oil. The real limiting factors for modern oils are not breakdown but combustion contamination. The guys over there at BITOG routinely test oils in between changes and report on exactly how it breaks down, how fast and what type of wear occurs. If you haven't heard those big rigs routinely go 50,000 miles between oil changes because they have excellent filtration.

i use rotella t 5w-40 in the wrx swapped subaru. it doesnt burn off as fast as others. however for the motorcycle; i use walmart no name 10w-40 SF for 2 bux a quart.

Accel from walmart 2.27 freaking hell, just 3-4 years ago it was 77 cents - 10W40 SF rating. Booya.
Cool.
Buddha.

Quote from: qwertydude on March 15, 2009, 08:49:34 PM
Would it only count if that person was on this forum?

No, not necessarily, but I would be interested in how a particular oil behaves in MY model, or one designed like it. (air-cooled, DOHC twin or 4-cyl with plain bearings)  How it runs in a Ninja doesn't relate, as we don't have a Ninja, CBR, GSX-R, YZ-R, or anything of the sort.  You wouldn't even think of putting that stuff in a Harley.  Harleys require 20W-50 and Harley dealers are adamant about using nothing else.

I guess the reason I find this subject interesting is because it's such a complicated science and our bikes put varying demands on oil, not to mention where we live or how we ride.  Where I live, oil gets dirty slowly, as it's generally not dusty here, nor is it very hot.  I change my oil after 3,500 miles or so, and it still looks and feels pretty good when I change it.  During such time I probably put in another quart several ounces at a time every few weeks to top it off.  I think DOHC motorcycles generally put more shear stress on oil than any other vehicle, but you correctly point out that diesels pollute oil like crazy with combustion waste, as diesel is very dirty compared to gasoline, and those acids cause oil to break-down as well.  Air-cooled bikes also pollute the oil faster with combustion waste than a liquid-cooled gas engine would, as the tolerances are looser.

I understand that a 5W-40 synthetic oil can provide outstanding viscosity to provide great engine protection, but the thickness of the oil film on bearing surfaces and valve stems and seals may not be as thick as our looser air-cooled engine designer would want.  That's why I'm reluctant to use 5W- anything in my GS.  I do use 5W-20 in my car because that's what Dodge recommends.  I've been looking for information that specifically addresses air-cooled bike engines like ours, but as of yet everything I've found is written in general terms or for other types of engines.

Old school CB750's are a good analogy to our engines and Rotella works just fine in them, plenty of posts about 1980's CB750's on BITOG about how well those engines run and shift with any Rotella and easily surpassing 100,000 miles.

And the biggest problem with specifically Harley dealers is that nowadays Harley dealers know absolutely bupkiss when it comes to actual bike maintenance and repair. My former boss used to own an independent harley repair shop. And was doing really good business before he sold it simply because the dealers usually refuse to repair bikes older than 5 years old, cause techs never trained in real motorcycle repair. Harley dealers also recommend "Harley" brand oil, transmission and clutch fluid and poo poo fancy stuff like synthetics, unless it's "Harley" brand synthetic, guess what harley is not an oil company so it's simply because you pay a big premium at the dealer that they recommend harley brand everything. Yet every BITOGer that runs synthetics in their Harleys report lower wear when doing used oil analyses. So take Harley recommendations with a grain of salt.

Oil is oil, it's not a magical substance that varies so much between brands that your engine will blow up without running factory specific stuff it's why there are API ratings in the first place to maintain consistency among oil companies, stay in the weight ratings and minumum spec and you'll be fine oh yeah don't forget to change it frequently also. Trust me it works because API designations are all backwards compatible. Recommending in house brand oil is simply a marketing scheme. Now there are very specific circumstances where there is a reason to use in house oil but that only really applies to extra long change oil intervals like you see in some european cars with 25,000 mile oil change intervals and those specific oils use more stable additives and completely different base stocks but putting that in something like a GS would be kinda dumb because we don't have the filtration necessary to remove the combustion chamber contamination.

And oil  among different engines does relate. Higher compression, higher revving engines are simply harder on their oil than a GS is, so what's good for them would be good for us. I can give specific examples of hotspots and shear forces but then I'd have to explain every single little detail on tribology, and it's all covered in BITOG which everyone should lurk and read if they even wanna think on forming an opinion on oil. Were GS experts here they're oil experts there. And like I said before the oil film thickness when warm is just the same with 5w-40 as it is with 15w-40, if it weren't there would be specific instructions by manufacturers that tell you not to use 5w-40 in 10w-40 applications, but the minor differences between the cold weights shouldn't even cause concern. In fact with more VII's in the oil the viscosity/temperature drop off should be even more stable at higher temperatures than plain ol' 15w-40 so valves should be just as protected again proved by the fact that there is less wear metals in Rotella synthetic than other oils. Trust me if rotella was a bad idea in any application that would have been quickly pointed out by BITOG, just like when they pointed out higher wear metals in old pre-reformulated Pennzoil.

All in all a simple blanket statement like "only use Suzuki brand oil in your Suzuki because it's the best" shows a complete lack of understanding of even basic tribology and unfortunately those are the hardest opinions to change.

Geez.  http://www.npr.org/blogs/monkeysee/2009/03/ten_toxic_things_you_should_ne_1.html  And number 11 is oil.