Motorcycle Forums » General

Synthetic Lube VS Motor Oil

    • 5417 posts
    March 4, 2009 2:14 AM PST

    This was a very popular topic on the old forum so I figured I would bring it back up.


    Would like to get your opinion on running synthetic oil vs standard motor oil and other petrolium based lubes in your bike like the tranny and primary.


    Would especially love to here from some of the mechanics we have here.

    • 5417 posts
    March 4, 2009 2:18 AM PST

    Ok, I'll be first...


    I have been running syn lube in my RoadKing (and my last RoadKing) for 6 years and over 75,000 miles on the first one and 20,000 and still going on my current.


    I have not noticed any difference in performace, but what I do notice is that when it comes time to change it, the old comes out much cleaner with a lot less metal shavings.  I can only guess that this is due to a lot less friction between parts.

  • March 6, 2009 8:48 AM PST

    I know this is a Harley tech category, but I'm going to throw my two cents in.


    In the racing world just about everyone has gone to syn lube. I know dino has been around for a long time and has done a good job for all of us over the years, but the times are changin'. The difference is with dino oil, it can only be so slippery because of the properties it comes with out of the ground. With synthetic lubricant, they continually improve it to do nothing be be slippery.


    At the track we care a lot about how hot our engines get, and with syn, they run much cooler because of the reduced friction. The reduced friction also cuts down on the wear and tear of internal parts saving us lots of time and money if we can go longer between rebuilds.


    Bottom line is oil has seen its day, we can make it better, stronger, faster...we have the technology!

  • March 8, 2009 1:10 PM PDT

    Here's some info on lubricants. I've been selling oils & petroleum products for over 25 years. With todays engines, especially air cooled, their running much hotter due to the unleaded gas we burn in them. With out the lead, theres less lubricant in the gasoline which makes the engine run at higher temps. In the state of Penna. we have two different kinds of gasoline. Summer gas and winter gas. The difference between them is the summer gas is oxyginated so it will evaporate easier or quicker in more humid weather. We also seem to lose a little mpg's this time of year. This is all due to the clean air act which was signed in 1992.

    Anyways. with the engines running hotter. petroleum based oils start to burn at approx 340 degrees. Once this happens, all the additives and lubricating properties cease to exist and you need to change the oil asap. If your using a synthetic, ie, Syn 3. or Mobile 1, these will take temps. over 500 degrees. For what they cost, $10 per qt., it's well worth it in an air cooled engine.

    I have seen Harley engines stuck in traffic and in parades run upto 340 degrees when the outside temps. are over 80 degrees.  And oil cooler work if your moving in the wind at speeds of 40 mph or more, so if ya live in a big city with lots of lights, don't bother...By the way Syn. fluids will run 10 degrees cooler in your engine that petroleun based oils.

    • 5417 posts
    March 8, 2009 3:27 PM PDT
    Thanks Coley, That is the best explaination yet on this subject.
    • 46 posts
    March 12, 2009 9:28 AM PDT
    I do agree with Lucky, it seams I have a lot less metal shavings coming out with the old stuff since I changed to synthetic. I am still not comfortable with doubling the milage between oil changes as the synthetic mfg's recommed.
  • March 12, 2009 5:59 PM PDT
    My best friend is an automotive engineer and long time Harley rider,he swears by synthetic oil and use Amsoil exclusively. His 98 Classic has about 90,000 miles on it without ever having any major top or bottom end engine work done on it, however he and I both still change our oil at 3,000 miles, 7,500 just scares the hell out of me here in Florida where oil gets real thin real fast.
    • 39 posts
    March 14, 2009 6:19 PM PDT
    I haven't been able to definitely tell for sure in any 4 stroke engines but I did swap from conventional to synthetic in a direct injection 2 stroke engine and I used far less synthetic than the old stuff. I'm talking almost half as much synthetic with no adverse effects. I figure that if the syth. is making the engine run that much more efficient in a 2 stroke, it has to be better in a 4 stroke as well.
  • March 21, 2009 4:25 PM PDT
    Okay, I will put another nickel in the slot. As with everything else, there is always pro and con to every subject. Even though the new synthetics do allow less friction and are more slippery the down side to them is this slippery action prevents the wet sump clutches from operating at full efficiency. When you use the full synthetic with the wet sump clutch it acts as though the clutch is slipping, even though it's not. What I have had the best luck with is a blend oil that is 20W-50 weight. As far as brand, I think that is a personal choice. Some love Royal Purple, others live and die by Amsoil. Being from the petroleum industry all my life I feel any top name oil with the correct detergents and viscosity will do the trick if you do what you are supposed to do when you are supposed to do it.
  • March 23, 2009 1:04 AM PDT
    Remember! When using a synthetic fluid in a motorcycle that has a wet clutch, you need to use an approved fluid.
    Not all synthetics are the same. The difference between them are the base stocks that they start out with as well as the additive packages they are putting in the fluid. For Primary applications, the approved synthetics for a Harley-Davidson are, Syn-3 20w50 created by Mobil 1 or Mobil 1 motorcycle 20w50. For Honda they have a Honda synthetic which has been used for years with no wear or should I say slippge problems. My 84 Goldwing had over 100,000 with no problems as well as my 88 Goldwing. Now in my 03 Ultra I personally use the Formula Plus in the primary but, I do know some bikers that use Syn 3 in all three areas and have over 50,000 with no problems. Remember, Harley stands by it...
    • 1 posts
    March 25, 2009 6:38 AM PDT

    I'm a self trained motorcycle mechanic for the most part, so I don't know all the technical specs of the synthetic lubes or the old dino oil, but I do know I wouldn't run anything other then synthetic in my bikes. Like a couple people already said, you just don't see as much gunk and metal shavings when you change the oil, and in my book that's a good thing.

  • March 31, 2009 4:04 PM PDT
    Howzit all,
    Just signed up and I am still trying to get the feel for the forums... Hope I am not off base bringing up this topic here. Sort of started reading up the comments in the different areas and stumbled on this one dealing with the "Synthetic Lube VS Motor Oil" bennies and cons... I just bought a '09 Electra Glide Classic. Bike will be out of the assembly and being delivered at a dealership in San Diego, Ca in June. I live in Palau Micronesia and have been out of the motorcycle business for a few years. Anyways, I have been reading up on the break in suggestions (nowadays) and I had a lot of fingers pointing me to a site by a guy called the MOTOMAN... His name is Pat McGivern and his site is at /> What he preaches is that there is a huge difference in the oils and that his experience (works with racing motors) has been that the syn oil should only be used (if desired) after the break in period. Something to do with dino oil being better for the breaking in period (first 20 miles) of the piston rings and walls.
    My reason for bringing this up? Does anyone have any words of wisdom they would like to share with this fng?
    Anybody tried his method? I would appreciate all the help I can get... Mahalo.
  • April 1, 2009 1:51 PM PDT
    There's not an easy answer. Back in the 70's prior to using syn products, weather it be in a bike or car the industry wanted you to use regular dino oil to break an engine in. Approx 1500 mile so that all the ring and valves would wear in to seat correctly. However, now in the new millenium, engineers have come up with better metal composits for the parts, ie; chromium, magnesium, copper and the such. There for when their building engines today, the tolerances are much closer than in the past and the machine work has been much approved. Thats why on all new corvettes, lamborghini's, porche, and the like as well as Harley-Davidson they put Syn fluids in the engine from day one with no problems. So, in closing, if you don't mind the extra expense, put an approved syn fluid (Syn 3 20w50, Mobil 1 Motorcycle V-Twin 20w50 , Amsoil 20w50 in the engine.These 3 fluids are approved by Harley Davidson while under warranty. Hope this helps.
  • April 1, 2009 5:13 PM PDT
    Thank you sir... I appreciate the tech advise. Did you by chance get an opportunity to read that guys theory on it? He has quite a following and the argument is well taken... Being a new guy to NEW scooters, I want to make sure I go the right way.
    Thanks again...
    • 1 posts
    April 3, 2009 2:39 AM PDT
    I would have to believe that Harley, or any manufacturer, would not send out a brand new bike with something in the engine they did not feel was the best product to break it in or run it on. (my 1ยข - times are tought and I'm keeping my other penny for an emergency).
  • April 3, 2009 8:56 PM PDT
    Alright BailOut... Glad you decided that the penny was worth spending.... I agree with you... HD has probably done their part insuring each one of their babies has gone out with the best chance possible of surviving all that yoyos like me are going to do with them... Just broadening my horizons a little and possibly, through people like yourself and Mr Coley, I can settle my beliefs that the world might be round after all... This guy, the motorman sort of touched a nerve and I cannot help but wonder if he is the new Chris Columbus of engine break in.... For what I paid for my bike, I had better make sure I am doing the right thing... Know what I mean...? Thanks for the point. Well taken.
  • April 4, 2009 8:56 AM PDT
    It comes down to how often you want to do your oil changes. Use regular oil and you'll be changing every 2500 miles. Step up to the Synthetic and you'll be doing your oil changes every 5000 miles on the engine and every 10,000 on the trans and primary. Synthetic really makes more sense...
  • April 7, 2009 1:17 AM PDT
    Hey Boomer... Thanks for the comment. I agree with everyone that synthetics is the way to go... My problem is that I am trying to figure out if the MOTORMAN (in the internet) has the answer on the break in thing. Man is convincing and has quite a following. I am a sort of an open minded kind of guy.... Always have been and hate to think that there isn't ways to improve everything we do... Check it out and let me know what you think... If you like do something like hd breaking in motorman...
    • 5417 posts
    April 20, 2009 5:27 AM PDT
    Something I found out this weekend about synthetic lube...If you spill it on your garage floor, rubbing alcohol will clean it up like it was never there.
    • 1 posts
    July 27, 2009 8:30 AM PDT
    Ok, we had the discussion, now I'm interested in how many actually use synthetic lube.

    Check out my poll Synthetic vs Motor Oil
    • 5417 posts
    July 30, 2009 5:23 AM PDT
    Please note that there was a comment on our site indicating a problem with the current Harley-Davidson brand synthetic lubricant. We have it from a reliable source at the motor company, as well as from several H-D dealers, that there is in fact NO problems with the current or any of the past H-D Synthetic lubricants. Harley Davidson dealers are continuing to sell the product as well as use it in their service departments.

    We apologize for any confusion the previous post may have caused.
    • 835 posts
    July 31, 2009 7:53 AM PDT
    Thanks for the clarification on that.
  • August 3, 2009 6:40 AM PDT
    Saw a couple of comments on the synthetic vs oil poll regarding Amsoil.

    Is Amsoil different then the other Synthetics?

    What makes it better?
  • August 5, 2009 4:34 AM PDT
    I have been running AMSOIL in both my harleys(ok one of them is the wifes) for the past four years. I average around 15k a year. I do a complete fliud change in the spring. I am running 20W-50 MVC in the Engine and the Primary and    75W- 140 SVO severe gear lube. I change my filter every 3-5K  add what is needed. My bikes run cool. The highest my 06 Road king 95 " has ever got with AMSOIL is 224. Below are some links that can answer some of you questions.   Thanks /> /> />
    • 1 posts
    August 11, 2009 8:38 AM PDT
    I have personally never ran Amsoil in any of my bikes, but I am hearing more and more good things about it. Guess I'll give it a try and let you know if I see any difference.