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Synthetic versus mineral oils

What is the difference between synthetic and mineral oils as it relates to motorcycles?

Driving a car I have always used synthetic oils where I could, but recently when I took in my little CB125 for it's first service they made the comment that they replaced the synthetic running in oil with a synthetic/mineral blend for normal operation. In my scooter I have always used Castrol 4T as this was what the shop that sold it to me reccomended. But it got me thinking, I have heard comments that in motorcycles we should be using mineral oils, and also that we should not be using oils which contain friction modifiers. Why might this be? A recent post on CCC discussing clutch slippage made reference to the oils used....

Does anyone have any comments about which types of oil we should be using? Also comments relating to friction modifiers would be helpful. Soon the bike I REALLY care about (the VTX) will be wanting an oil change before I ride her, and I want to be sure that I am using the best fluids possible in her.

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15 Comments

Now this is a great question!
Here on MotoTribe we have 4 pages of discussions on this topic... and many deal directly with the VTX! Check them out: http://cruiser.mototribe.com/search/site/synthetic%20oil?f[0]=bundle%3Ad...
I ride a 2003 VTX 1300S and I use a semi-synthetic. Mineral is great, but I prefer an oil which will give me many of the benefits of synthetic at half the price.
This is an interesting oil discussion:
https://www.youtube.com/watch?v=4q59ogKubPo
Bottom line, it is the blood in of your motorcycle... keep it clean, keep it fresh, and you will be good for many miles to come.

Mark, this one of those topics that comes up the most and gets many varied opinions. It is also one of the most misunderstood topics and one that is the subject of many myths. You made reference to “mineral” oil; which is not identical to the conventional petroleum based engine lubricants. Straight mineral oil is commonly used during engine break in (particularly in aviation) because it has less lubricity than conventional oils and aids with ring seating and other engine parts wearing in. So you do NOT want to run straight mineral oil.

Now, let’s talk about petroleum based engine oils vs. synthetic oils. There is not a blessed thing wrong with petroleum based lubricants. I have run many an engine past 200,000 miles on petroleum based products and have never had a problem. Yet I run Amsoil synthetic in my Road Star. Why? Synthetic oils offer a few advantage—they flow better when cold and they are better at resisting thermal breakdown. Heat is not a real issue on my 1997 Chevy truck, but the 1700 cc air-cooled engine on the Roadie is a horse of a different color! And because I normally ride year-round, I like the fact that it flows better on cold startups. In addition, synthetic oils allow extended drain intervals. By the same token, I have run petroleum based oils in other bikes with satisfactory results.

One of the most misunderstood concepts is the belief that it is mandatory to run “motorcycle oil” in your bike. Nothing could be farther from the truth! Your manual lists a minimum requirement that the oil must meet; you will see something like “must meet or exceed SG” or something like that. So believe it or not, something off the shelf at Walmart could be used in your bike. In fact, for those that wish to run petroleum based oil, one of the best out there is Shell Rotella. Because it is refined for use in heavy duty applications, it has higher levels of phosphorous than most other oils which acts an anti-wear agent. The reality is, the oil that the motorcycle dealer sells, whether it be Honda or Harley and anyone in between, is not manufactured or refined by them. So it is not “motorcycle oil;” it is oil that has been refined to meet the requirements set forth by them.

As far as friction modifiers, they are a big no-no! While they may be fine in cars, they will raise heck with wet clutches so don’t even consider anything along those lines. Long story short, your choice of oil really comes down to that—personal choice. If your riding conditions dictate that you would need the added protection against thermal breakdown as well as cold weather operations, then synthetic is the way to go. I personally like the Amsoil, but there are others available. One of the myths that exist is that once you have run petroleum based oils that you will damage your engine if you switch to synthetic. And that’s all that it is, a myth. If they couldn’t be mixed, there wouldn’t be synthetic blends, now would there? Synthetic blends are a good option if you want the synthetic option without the cost of full-synthetic. Let me know if you have any other questions.

Good feedback Bob!
I do know that USA riders of my bike often put in Shell Rotella T6, which is not a m-cycle specific oil and everyone seems to love it. I haven't found it in Oz for sale.
I prefer synthetic oil for its resistance to breaking down (I believe its called 'shearing')
I am currently using Castrol Power 1 Racing (full synthetic) in the V-Star 1300 and Castrol Power 1 GPS in the V-Star 650 (semi-synthetic).
Mark, if you wish to travel further down this slippery slope of oil discussion (pun intended) do some reading here: http://www.bobistheoilguy.com/

thanks for the info. into my favorites

yamaha semisynthetic in my vstar and it started to foam, even after 3 oil changes, switched to penzoil motorcycle oil 20 50 no foam no problems

This one popped up a week ago as well
http://cruiser.mototribe.com/discuss/oil-change-1 and my response is on there.
One point that has been missed is that a lot of car/truck oils do have friction modifiers added in Australia and as Bob says they are no good with wet clutches. This is most likely the reason you have been told to use motorcycle oil. One of my best mates, father was a chemist with Mobil and he told me all the modifiers that were put in oils here. Contrary to public belief, petrochemicals in Australia are only made at a few locations around the country. Each brand buys the product in a raw state and adds their own cocktail of modifiers to do what they claim makes their product better than the rest.
As I mentioned in the other post, air cooled engines need a good quality oil not only for lubrication but also for cooling. Synthetic oil does not break down as rapidly as garden variety oil, it does not get the carbon buildup or the sulphates of carbon based oils. Remember that diamonds are a form of carbon just like oil. Diamonds are used as an abrasive.
In any case you should read the manufacturers recommendations above all else. They recommend it for a reason.

Thanks for your responses everyone. Bobistheoilguy certainly has the good oil (sic) in his Oil University series; his pages made interesting reading.
Based on his info, your reply posts, and the info contained in the links I think that I will use an oil that meets the following criteria in the VTX (and probably more generally for the other bikes in the household):
Synthetic (which should provide thinnest oil at startup versus mineral or blended oil, along with other benefits described by Bob The Oil Guy)
Lowest first rating number ie 0W or 5W (again for thinner oil at startup)
No friction modifier (as reccomended by the forum here)
A premium brand (which will be easy enough to repurchase again in the future when I need to)

I think I will trial 0W (or 5W) -30 first and see how that goes first.

Not knowing the history of the VTX for it's first 3500km of life I am planning to make the first few oil changes at more than reccomended frequency also to help remove any deposits that may exist within the engine.

Cost of one oil versus another is not for me a deciding factor since I see the value of preserving the engine and minimising startup wear as more important. With respect to the scooter and the CB125, the cost savings in comparison to driving to work in a car (ugh!) provides savings far in excess of any increased costs of using a premium over a non-premium oil.

One thing that has become aparant to me from the literature is just how important oil is to the performance of the vehicle: perhaps another reason for using a known premium brand.

Always use a good name brand oil,Never a cheapie Mark

I had a look at one of the manuals downloadable from links here:
http://www.vtxcafe.com/showthread.php/3614-VTX-1300S-Service-Manual-down...
and it mentions 10W-40 oil.
And some more info here, and I note it mentions that there are 2 oil drain plugs on these bikes: http://www.vtxcafe.com/showthread.php/21645-Answers-to-Common-Questions

Went to the local Repco store today and had a look at oils while I was there. Noticed that I could get 0W-40 Mobil 1 fully synthetic for $90 aus for 5 litres. I believe this to be a high end product after all it was the most expensive oil in the store. Following a previous comment I was surprised how expensive it was. I stand by my initial comment though that the savings made riding easy offset the expense of a premium oil ( and thefore I will as initially indicated use a premimum oil in my bikes), but just the same ouch.

Besides irrespective of the reasons we give others for riding (even cost savings) thats not the real reason we ride now, is it....?

One more thing I would recommend Mark, when it comes to the weight of the oil it is a good idea to stick with what the bike manufacturer lists in the manual. Without getting into a big long thing here, the recoomended oil weight is based on not only operating parameter of the engine but part clearances inside the engine. Changing to a different weight may affect oil pressure. Just food for thought.

After the 600 mile drain of factory oil I requested the Honda service tech install the Honda HP4 full synthetic oil in my new 2009 Honda VTX1300R. I believe that it might be Mobil 1 in disguise as their car oil is. Ran for a year or two with
this then switched to Amzoil 10w40 full synthetic and believe it to be one of the best available. Not a cheap oil by any
means but I believe it outperforms many others in the same field. I change it once a year, at the end of the riding season before I put it up for the winter. It usually has 6-8k miles of use. This is okay by Amzoil as their synthetic oils are designed with this in mind.

I LIVE IN S. MISS. WHERE TEMPS SOAR IN SUMMER! VERY HOT. I AM 73 AND OWNED 18 BIKES IN MY YRS. OF RIDING AN STILL "WONDER" WHAT OIL TO USE????? EVERYONE SAYS DIFFERENT. DEALERS WANT TO SELL OIL SO THEY RECOMMMEND THEIRS. MY QUESTION IS WHY USE SEMI-SYNTHETIC AND NOT FULL SYN. OILS??????
AND ALSO FOR 20 YRS. I USED PLAIN 20-5O CASTROL PETROLEUM OILS AND NOT SYNTHETIC CASTROL..-- AND NOT CASTROL MOTORCYCLE SPECIFIED OIL. I FELT IT WAS PLAY ON WORDS BY SEELLER???? NOW RIDE 650 YAM. ONLY DUE TO WEIGHTS AND FUN BIKE. SORRY GUYS BUT HARLEY WAS WORSE BIKE I EVER RODE.---WENT BACK TO JAPS. NEVER HAD A WRENCH ON A JAP BIKE.
WHAT DO YOU THINK??????????????????/ I CHANGE OIL EVERY 2,000 MILES--MYSELF-- SO DEALER TOLD ME DONT MATTER WHAT I USE.. REG. OIL OR SYNTHETIC.?>????? I WELCOME EMAIL REPLIES.

20w 50 drag specialties I used penzoil before but apperantly they stopped making it in canada

I only use full synthetic. Currently on Castrol Power 1 Racing 5W-40 and have been using that for about 4 yrs.

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