The Great Oil Debate – Synthetic or Conventional

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December 20, 2010 | By: Lowell Anderson

There’s been an ongoing debate for decades over what oil is best for your machine and my thinking tells me there’s no standard answer to that question. That’s because there are too many variables — the climate you live in, the amount of time you spend on the road, the type of bike you ride. A lot of folks will tell you that synthetic is the way to go, but that’s not always the case.

Where you live is an important consideration in your choice of oil because of climate considerations and oil flow rates. And synthetic oils definitely hold an advantage in the cold-weather department. High-viscosity conventional oils simply don’t flow in cold temperatures, and even low-weight conventional oils stop flowing at around 34 degrees Fahrenheit.

Synthetic oil will flow at minus-50 degrees Fahrenheit, a serious advantage if you live in a cold climate. Almost all of the wear in your engine occurs during start-up. If you live in a cold climate and you fire up your bike from time to time during the winter months, you could be doing some serious damage to your engine. Synthetic oils also perform well in high temperatures. Some synthetic oils can offer protection at temperatures up to 400 degrees Fahrenheit. Conventional oils tend to fail at around 270 degrees, although this is seldom an issue since bikes normally run under the 270 mark. But if you have a bike that runs low oil pressure, and could touch the 270 mark on occasion, you should definitely consider using synthetic oil.

The type of bike you ride is also a major consideration when choosing oil. For instance, if you ride a motorcycle that uses the same oil for the clutch as it does for the engine, conventional oil is the way to go. That’s because synthetic oils are “slippery,” for lack of a better word. This can cause major problems with a clutch, because clutches need some friction in order to work properly.

When it comes to the pocketbook, of course, synthetic oils are more expensive. A lot more! There are many benefits to using synthetic oil, but saving money is definitely not one of them. It costs money to develop these highly efficient oils and the end user pays for it. In some cases, you are paying much more than what is considered reasonable, and that may be due to the name of the product. As a rule, synthetic is about 50 percent higher in price than its conventional counterpart.

One thing that conventional oils and synthetic oils both have in common is their ability to get dirty. There are synthetic brands out there that claim you can run their oil for 20,000 miles or more without an oil change. But having that dirt run through your engine for 20,000 miles or more is not a good thing. Your oil should be changed at regular intervals (usually 3,500-5,000 miles) whether you run synthetic oil or conventional oil.

In most cases synthetic oil is the best choice. Conventional oil is fine for those riders who live in a mild climate, change their oil like clockwork, and ride a bike that uses the motor oil to bathe the clutch. For the rest of us, our bike is best served by spending the extra on the synthetic oils.

Comments: 42 Comments | Categorized Under: Product Information

Comments (42)

I have used valvoline conventional 20-50 for vtwin in my victory jackpot for 55k miles… the guys at the dealership freak out when they hear that but I think I is really bc they want to sell victory oil for a huge profit margin. No synthetics for this guy. I’ve seen way too many race cars blow their shit up bc of synthetic. It’s like vegetable oil when it gets hot.

I wouldn’t use Dino oil in my lawnmower. Fact is; AMSOIL is in my lawnmower, snowblower, 2 P.T.Cruisers, one with 242K miles, still runs strong, 2 Evo H-D’S, 1976 Caddy, 2012 RAM C/V & just last week, after break-in, had our new GMC Terrain, entire drivetrain switched to AMSOIL, NO GM dexos BS scam for us, WE know better. PS, every race car at DAYTONA, INDY 500, NASCAR, SEBRING, LEMANS, all the Grand Prix races, are all using SYNTHETICS. And these cars are all water cooled, so maybe, just maybe, Synthetics would be better for your air cooled Harley ? Or maybe, YOU like scraping sludge out of your motors !

I use syn3 in CVO, I use Mobil 1 in Acura TL. I believe in synthetic oil. It last longer and resist heat better than conventional oil.

I know I don’t want to go 20,000 miles I don’t even do that in my big truck but I was wondering if I might be able to get 7, 000 out of it.

Hey Russell, I’m an AMSOIL Dealer, since 2004. We have Big Rig Fleets around the USA, going 50, 100, 200, 400K between oil changes ! Cummins forbids you from using Royal Purple, because of the Moly, & Shell Rotella, well, there’s nothing good to say, but, it’s cheap, in more ways than one.

My comment about seven thousand miles was based on if I switched from conventional to synthetic somehow my post talking about that did not make it

I’ve been using Mobil1 20W-50 since I bought my new 1993 Softtail Springer and installed the oil in my 1981 Heritage Edition. The Harley racing team in Dallas suggested it cause they were using it and they were winning. We installed the oil when setting up my new ’93 Springer. I did a lot of research on synthetic oil also.
Mobil1 20W-50 for Twins has the addictive to keep clutches from slipping. The standard Mobil1 20W-50 does not and that’s the only difference. Mobil1 also has a synthetic oil filter for Harley Twin-cams.
I’ve been told some synthetics claim 25,000 miles between oil changes.
I use to run 7500 miles on my shovel but changed filters at 5000.
On my ’93 Springer I ran 10,000 miles between oil changes, filters at 5000. Bike has over 100,000 miles now without any problems.
My ’02 Twin-cam has just over 80,000 miles and I change oil and filter at 20,000 miles.
I checked the cam chain tensioner at 60,000 miles, some wear but not too much. Did a 96 big bore, cams and hydraulic cam tensioner plate at 70,000 miles The cylinders had minimum wear. No ring ridges. I didn’t even have to replace valves or guides, they were almost as new.
I wish now I’d taken pictures of the engine when I installed the 96 big bore.
Most old timers as I would have guessed the cylinder wear about 2500 maybe 5000 miles.
Oh yea I won a 2006 883 Sportster and after switching to Mobil1 I had to turn the idle down. It was already setup when I won it so I had to change it out after the initial ride.
Hope this helps but verify everything, always. (My engineering coming out)

I am wondering if a good quality engine oil, designed for use in 18 wheel truck diesel engines with the same weight grade recommended by Harley Davidson, would be beneficial in a 2007 twin cam engine. Those oils have a lot of engine life extending additives and are designed for high-temperature operation.

We would not advise using a diesel oil in your twin cam. The wear additives in that oil are not the same as what is designed specifically for motorcycle engines. The additives and the amount of additives used in motorcycle oils are specific to the temperature ranges and friction needs.

Your H-D manual states, if your low on oil, & nowhere near a motorcycle shop, it’s OK to put in a qt of Diesel oil, but, change your oil ASAP.

Jim regarding that engine for my fat boy ,s&s only build the evo style my engine is twin cam b which is internal balance. Also i up graded to the 95″ to about 100 hp plus harley said they will rebuild back to the 88″ about 67 hp.that doesnt work for me.also i took my bike to red deer harley davidson to get repaired ,they told me to take to the harley dealer where i bought it back in 2000.i took it back to hertige harley in edmonton ab. I didnt have no problem with them.so after that deal with red deer gasoline harley i decided i dont need there junk. I looked in the service book there is no mention on the twin cam tensioners to be checked. I only have 36000 km on the bike.

I use Lucas Synthetic 20/50 in my 2003 CVO Road King. I have updated to S&S Gear Drive with Feuling oiling system. Have no negative issues with Lucas products !

LOL- extended? OK ya Moran’s….I quess your engine doesn’t make any ACIDS or other metal destroying FLUIDS ….Oh yeah , you have an Acme acid removing filter!!!! Syns are fine, but Fossils or Syns need changed regularly to remove liquid contaminates. Except yours. I’ll see ya when your scratching your ass and bringing it to my shop for repairs.

I’m running Amsoil with the Amsoil Filter and am completely sold on it. Using the Amsoil Filter is what gives Amsoil superiority. One year oil changes now.

I use to use HD Syn3 on every change for my 94 Lo Rider and 05 Ultra. Then after I had installed an oil sump temp guage on my Ultra I tried AMSOIL 20w-50 with their high mileage oil filter (comes in chrome too). I am totaly sold! That TC88 runs 15-18 deg cooler, no bull.

Yes the upfront price is more but with the longer oil change intervals I save $$’s. I now use it in every engine I own including my lawnmower and snow blower.

Macdad

owned many of harleys close to forty years,being a machinist/machanic ive built countless harley motors my pan ran better and cooler with 20/50 conven oil than stright wt.oil the name of the game is to get oil through motor, filter,cooler(yes every bike should run a cooler)as fast as you can back to tank stright weight seems to hit filter and slower to get through it,oil pump doesnt stop pushing more oil in keeping oil in your motor longer runs hotter starts looking for a way out (leaks) as far as synthetic vs conven rebuilt 2 s&s motors that switched to synthetic both rod bearings both under 40 thou miles then there are bikes(tc) running synthetic with 100 thou miles and never done a topend amazing!so i dont know but the one thing i do know is that OIL IS CHEAP comparied to a rebuild keeping your oil & filter changed every 3500 mi and many years of enjoyment but you can do what abuse your motor and you will be seeing me !but that is ok because i like to eat!

No synthetic oil in 60 wt available so my Pan Head will stay with Valvalene Racing 60 wt.

I use Amzoil 20w50 in my 89 HD bagger, I seem to have more upper end noise but motor stays cooler. Im not sure if I want to change back or not. I don’t like the noise.

I use synthetic oil in my 2009 Yamaha V-Star 1300 ( and also in my 2001 Isuzu Rodeo and 2006 Chrysler Sebring conv.) I use AMSOIL in them all! Of course the oil for the motorcycle is different than the AMSOIL for the automobiles. I am pleased with the results in all of my vehicles. If you go to the AMSOIL web-site and inspect and study the comparison tests concerning AMSOIL’S motorcycle oil, all of you will switch to AMSOIL. It is a great product!

i use harley 20-50 in my 103 trust it and keep it changed every 3500.Tried syn in my 86 evo and i thought it got a bit noisyso i switched back H D 20-50 ,i’m thinken i might try 20-50 syn in it this year
AL from ont.

Syn vs conv, well whatever you use the thing is, change your oil often. In the long run you’ll be glad you did.

On the discusion of oil. I was told that the older Harley’s, shovelheads and early evo’s, that synthetic oil would have more of a leaking issue, than regular oil. Any truth to this rumor?

Hey John..Ya make a good point there about the Slippery comment…but the additives are already in the oil..Can you buy oil without the additives??

Google API Ratings for motorcycle Oil’s. Synthetic oils ARE NOT BY THEM SELVES “SLIPPERY”. It’s the additives in both the regular and Syn. oils that make them “slippery” Do your homework………..
Synthetic oils are superior to dino oils for a host of reasons. One is the carbon chains are of equal legnth and the impurities of dino oils are absent. ( parafins, shelac type compounds and others.)
The ‘energy savings’ rating on the container is the give away. Also some use automotive oils in their bikes. NOT RECOMMENDED…..Read the article’s on the Google search…… most will be supprised on just how a good and untrue rumor keeps going.

In the Top End of Australia it is pretty hot most of the year. Mobil 1 is the oil of choice for a lot of Harley riders up here. Most use it in the engine, primary and gearbox. Pretty cheap insurance

’88 Heritage Softail, bought new, always got 40-42 mpg. After 21 years, switched to Amsoil – have not gotten less than 51 mpg since.
I now have Amsoil in my Shovel, Evo & 103 TwinCam. Love it!

Changing oil and filter (between 3 to 5,000 miles) is
most important. Oil does not wear out……it just gets
dirty with contaminating elements which cause wear.

For my 2003 Honda VTX 1800 C, I’ve used nothing but the Mobil 1 Racing 4T 4 Cycle Synthetic 10W-40 Motorcycle Oil since DAY 1! Use the M1-110 Mobil 1 Oil Filter as well. I’m not a hot rod rider by any means. I change oil 1 time a year as this is usually less than 5K miles. Back in the day, I rode my 1981 Honda Goldwing to just a tad over 123,000 miles using Mobil 1 oil. Motor was still as tight as a bulls but at fly time.
I’m sold on the synthetics as well as the Mobil1 Synthetic rear drive housing lube. No clutch problems with either bike!
And………….. the beat goes on!

I did the research last summer on Amsoil and am now a believer!! I put it in my 2005 HD Sportster 1200 with 32,000 miles and I ride really hard, I put 300 miles on it and I noticed a difference right away with heat, quieted down the top end and smooth shifting. I live in Oklahoma and ride when I can so I depend on it to start everytime. 1 yr or 6,000 miles is the way I roll now, go to the Amsoil website and do the research, you’ll be pleasantly surprised and you wallet will too with less oil changes the big companies have drilled into our heads.

I have been building Hot Cars and Riding Bikes since the 70′s. Back then I used Castrol GTX 20w50 in everything. Today I use synthetic.

The High Perfomance Bikes and Cars I build today last longer because I change my oil frequently and don’t mind spending the ca$h to protect them.

Everyone will have there own preference. But if your new to Bikes or High Performance. Use a good quality oil synthetic or conventional and change it often 3,000 – 7,000 max.

I PUT THE BEST SYNTHETIC IN MY V STAR 1100, AND I NOTICED MY CLUTCH DOES DRAG SOME , @ 15.00 A QUART ITS GREAT LUBE , BUT I WILL BE SWITCHING TO A BLEND , HOPEFULLY THE BIKE WILL NOT DRAG ANYMORE

There’s always a gimmick and synthetic oil is one of them. I have owned many bikes and cars and NEVER touched synthetic. I bought my 60 Pan from a friend that owned it for 8 yrs and I bought it from him and have owned it for 26. Hell the bike is 51 yrs old and you know they didn’t have synthetic back then. I use straight 50 in the winter and 70 when it hits high 90′s in Fl. and never had a problem relating to OIL. If you want to be a Knucklehead (Not H.D related) and spend the Cash, then synthetic is your oil. If you use it just so you can add miles before an oil change, I’ll be passing you while your smoking on the side of the road….THE END

I switched to Golden Spectra 4 since the late 80s (or early 90s) and ride from the east coast to the west coast at least once a year, averaging 800 to 900 miles per day. Sometimes in 40 degree weather and sometimes in 110 degrees, and I’ve never had a problem with any of my bikes overheating or having a problem starting. Which I occasionally did when I ran conventional oils. I now run Amsoil, cause I can’t find Spectra around here half the time, but my bikes run cooler, quieter and so it’s worth the extra cost. And yes I do wait to change the oil until 6K to 7K.
Enjoy…

I switched from dino to Royal Purple in my bike (with a wet clutch) and it shifts much better now than it used to.

Synthetic is in many ways superior to traditional oil.
Depending on the application, hoses, seals etc. not withstanding. If its not on the ground after its been in the system awhile, then you are probably alright.

As far as extended oil changes, think about this: the filtrations system will accumulate more contaminants and possibly even restrict the flow at this juncture, some contaminants that are caused by chemical change brought about by heat will still be in your oil, and during cold weather operation excess fuel will dilute your oil depending on the age of the bike and the carburation/fuel injection system.

Go with the manufacturers recommendations for lubricants and you can’t go wrong, they have put time and money into research and development and engineering.

Hey Bill, the only research H-D did, was to develop a way, to get every last dime out of your pocket ! SYN3, made by Hugo Chavez’s CITGO, NO THANK YOU !

I don’t give a rats a** about Hugo Chavez what I do care is about my bike’s have been running synthetic since they became available, although there does seem to be a little more engine noise never had a problem between my 96 Wide Glide, 2005 road king and my 2013 street glide with a combined klms of a little over 200,000 and all still running with no major repairs!!

My HD dealer tells me that for our Canadian climate, synthetic oil is the way to go. And I trust my HD dealer!

i started useing synthetic oil in the 90s on my 1990 flhs harley,moblie one , and mixing it with durelube my bike never over heated in daytona ever one i rode with wouled ask me about it why my temp was so low on the bike so id tell them, saw the testing they did on durelube and i was sold never had one problem with the bike in any way,after useing synthetic oil.

I’m with Herg, I use synthetics in everything in everything. I have a wet clutch and have never had a problem with it due to the synthetic oil. I also practice extended drain intervals because synthetics don’t break down like conventional oil does.

My name is Greg Riddle of VTXOA and I am a know it all. All, I will use is AMSOIL because their alleged “Independent Tests” tell me that they are the best out there, so it doesn’t matter what you all have to say.

I won’t use nothing but Synthetics, use it in everything I own, and also practice extended oil drains.

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