Oil makes my head hurt

[MisterCinders]

I know that the OIL WARS are eternal among motorcyclists and don't want to spark that debate.

For a novice like me, however, I cannot find a straight answer on the appropriate oil to use for my 1978 GS750.

The owner's manual suggests 10w40, but looking at any 3 information sources gives me 7 different recommendations.

Before I change the oil on this bike, I place my head in your hands.

I live in Chicago (i.e., cold) and ride only occasionally, for short distances with a fair bit of stop-and-go city riding.

What is a boy to do?

Mister Cinders

[JEEPRUSTY]

yay oil thread

[bobthebiker88]

you already know, you're going to get a LOT of opinions on this.

Personally, as a hobby mechanic, I swear by Rotella 15W40 for everything. even my lawn mower.

[tkent02]

Rotella .

[Steve]

Yes, everybody has their personal favorites (another Rotella fan here), but one universal caution is to make sure it does NOT have the "Energy Conserving" designation in the API 'donut' on the back label. So far, I have not seen anything over 30w with that designation, so stick with just about any 10w-40 and you should be OK.

Change it more often than you change your car's oil. The oil in the bike also runs through the transmission that imposes different stresses to the oil, so it gets worn out quicker.

Do not use any 'moly' or Teflon additives in the oil. The oil also runs over the clutch. Most of us like the clutch to hook up when the lever is released.

Probably more items to consider, but I will let the others point them out.

.

[bonanzadave]

Im a convert

After listening to a lot of GSers talk about Rotella T I happened upon some for sale at Wally World for $9.50 a gallon. I bought 2. One in the bike and one in the boat. Im sold .

From the Rotella web site......

Can heavy-duty diesel oil be used in motorcycles?

Motorcycle gasoline engines may not seem in the same league as the big displacement diesel engine under your hood, but they share some of the same lubrication requirements. So yes, in many cases, a premium heavy-duty universal oil capable of serving both diesel and gasoline engines is the best choice for your bike.

The high power-to-displacement ratio of a motorcycle engine means rod and main bearings are subjected to loads that are not normally found in passenger car engines. The valve train is also highly loaded, and requires extreme pressure boundary lubrication. The same can be said about gears in the transmission, which are normally lubricated by engine oil. Oil additives containing phosphorus protect these highly loaded extreme pressure areas (in both gasoline and diesel engines). Because diesel engines have higher loading of components, more of the phosphorus-containing additive is present than in typical passenger car oils. And with advanced catalyst systems for gasoline engines, the phosphorus content has been declining in passenger car oils.

Since many bike engines are air-cooled, and tend to be operated at high power outputs and speeds, their lubricating oil needs to be more resistant to high temperature oxidation. That?s another advantage of a premium universal oil. Another thing you want in your motorcycle is oil that has excellent viscosity control, so that with use it retains high temperature viscosity. Some multiviscosity grade passenger car oils, subjected to extreme loads, can quickly thin out. Their viscosity can drop to the next lower grade.

One last thing to consider is whether oil contains friction modifier additives. For improved fuel economy, most passenger car oils have such an additive. But the wet clutch in your bike doesn?t perform right with friction modifiers. Universal engine oils don?t have friction modifiers.

Be careful choosing diesel oils. Not all of them are universal. In addition to the API Service Category CI-4 PLUS for diesels, look for API Service Category SL.

Premium universal oils like Shell ROTELLA? T Multigrade are formulated for heavy-duty performance, and your bike engine has some heavy-duty challenges for oil. For optimum performance, be sure your oil is up to the challenge.

[Nessism]

Modern automotive oils are bad for use in a motorcycle; not enough high pressure additives anymore (zinc and phosphorus) since EPA mandated the reduction to increase catalyst life in cars. Diesel engine oil is good for motorcycles, as are the various motorcycle oils, although they cost several times more and are not worth the price in my opinion.

[JEEPRUSTY]

Modern automotive oils are bad for use in a motorcycle; not enough high pressure additives anymore (zinc and phosphorus) since EPA mandated the reduction to increase catalyst life in cars. Diesel engine oil is good for motorcycles, as are the various motorcycle oils, although they cost several times more and are not worth the price in my opinion.

15 bucks a litre for Mobil 1 v twin oil
utterly insane you could change oil two or three times for the same price

[tkent02]

15 bucks a litre for Mobil 1 v twin oil
utterly insane you could change oil two or three times for the same price

V twin owners pride themselves on spending huge amounts of money for poor products. They'll sell a lot of it. If it said Mobil 1 Harley Davidson Oil they could sell it for twice as much.

[GTGS]

Was using Castrol Semi Synthetic then kept hearing about rotela. Changed the oil over to Rotela T (15-40?) I think. Anyway, the bike shifts smoother less clatter and I couldn't believe how much smoother the bike felt. Will continue to use it!!

[NoH2Oh]

V twin owners pride themselves on spending huge amounts of money for poor products. They'll sell a lot of it. If it said Mobil 1 Harley Davidson Oil they could sell it for twice as much.

Oh, if that ain't the truth. Talk to some of the Buell guys....sheeeeesh. I was one of 'em.

Used Rotella for the first time after getting my 78 GS750 mostly because of the advice here. No issues at all, and at 27.00 for 3 gallons at Sam's I can afford to change it on a very regular basis.

[Steve]

Was using Castrol Semi Synthetic then kept hearing about rotela. Changed the oil over to Rotela T (15-40?) I think. Anyway, the bike shifts smoother less clatter and I couldn't believe how much smoother the bike felt. Will continue to use it!!

You could also spend just a few bucks more per gallon and get Rotella synthetic.

That would be the 5w-40 in the BLUE jug.

.

[BassCliff]

Hi,

From your "mega-welcome":

A Few Words About Oil
I'll tell you what I use and why. I use Rotella-T Heavy Duty 15w40 oil. It is actually diesel engine oil and contains more anti-wear additives, phosphorous and zinc, that these older high-revving engines love. At about $12 a gallon from Wal-Mart, it's less than half the price of many motorcycle-specific oils, and is the best "bang for your buck" value. The synthetic Rotella-T is just fine too, it won't hurt your clutch. If you like, continue reading the links below for everything you ever wanted to know about oil but were afraid to ask.
Here's a great article on motorcycle-specific oil in general.
Here a 2nd great article, also on motorcycle-specific oil.
Sport Rider Magazine ran a feature awhile back on motorcycle oils as well, and included some testing with detailed results provided. Well worth the read!
Sport Rider "Oil's Well That Ends Well" Part 1
Sport Rider "Oil's Well That Ends Well" Part 2
Richard Wildman (of Richard's Corvair) explains in layman's terms all about grades, viscosity, shear, additives, specs, etc.
Richard's Corvair - Selection of the Right Motor Oil for the Corvair and Other Engines

And, of course, Bob the Oil Guy is a fountain of information.


Thank you for your indulgence,


BassCliff

[sschering]

Has anyone tried Chevron Delo 400? It's another Diesel blend motor oil..
We used to run it in the wet clutch 8v71 Detroit diesel powered buses..
Good stuff.. those motors were super clean..

I'm running Rotella in the GS's.. Nothing to complain about..

[Truth]

I'm just south of Chicago and use Rotella T 15w40. Seemed to be the general consensus around here, and it's cheap. BONUS! I always have a gallon jug on hand in the shop now.