Harley Lubrication

Lubrication and Your Harley Article courtesy of Donny Smith of Heavy Duty Cycles

There are two main types of lubrication: oil and grease. Which system is used depends on three factors:
1. Speed of rotation or oscillation. 2. Operating temperatures 3. Whether heat has to be removed from the area of lubrication.
If a function of the lubrication is to control or cool friction-generated heat, then preference will be given to oil, which can flow away, dissipating heat while recirculated oil is introduced to induce relative coolness. Grease is used when the bearing operates under normal speed and temperature conditions. An advantage is that it is cheaper–although cost should not be a concern on a motorcycle like Harley Davidson, where a need for quality should dominate price. More important advantages over oil is that grease offers better adhesion and provides protection against dampness and external impurities. A word of caution, though…since the best quality grease is designed to fight water (as in condensation) or normal rain, not the nozzle of a high-pressure jet hose that riders love to direct at vulnerable weeping wheel seals. Oil is used when the speed of rotation and temperatures are extreme, like inside an air-cooled engine like Harley Davidson.

More is Mandatory

A second trait of Harley riders is that bigger is better or more is mandatory. This gluttonous attitude is reflected in too-big cams that produce less power, bigger carburetors that deliver too much gas and louder exhausts (as in drag pipes) that decrease horsepower. It’s the same for lubing. With lubrication, riders love to overdo their perception of quality.

Two examples are:

1) The almost religious use of 70-weight oils by pre-Evo riders. There is no known use for 70-wt. oil and it’s only produced for marketing reasons to satisfy customer demand, not a Harley engine’s needs. I explain this ad infinitum to customers in my store, but it remains a best seller. Its use just makes the owner feel better and feeling good is what it is all about. 2) Instead of using a recommended grease or reading the can to see if it is appropriate with say, wheel bearings, the rider will purchase too thick a product that’s too stiff for this use.

So what happens?

On initial takeoff the bearing rollers must accelerate too rapidly under load and, instead of rolling or turning, they slide. As they slide, they cut through the all-important lubricating film that separates roller and mating race; now we have metal against metal, causing hidden damage. I hesitate to mention here that there are “synthetic” greases knowing the lust for synthetic oils or miracle lubes advertised on late night t.v. infomercials. Synthetic grease is better and use it if you like, although the reader should realize that its primary advantage is low frictional resistance at low temperatures down to -70 0 C. If you ride in that kind of weather you are a better person than I. Before using miracle lubes that allow your engine to run without oil for 13 years remember the example of skidding as opposed to rolling rollers. Is the miracle lube designed for an air-cooled engine that uses the types of bearings in your bike and the types of metals that rub against each other? Oh! We don’t know this information. Well, well. Maybe we should curb our innate desires for “bigger is better”. In fairness, some of these coatings do work. For example, Harley has started using black Teflon coating from the rings down on Sportster pistons to assist in break in and will expand this use to Big Twins in 1999. Also new are bottom end roller cages having a slippery copper like substance on them for the same purpose. More on synthetics later, but before merrily using them, be aware there are five kinds: diesters; silicones; fluorinated; polyglycols and syn-hydrocarbons. Sorry for laying the big words on you. I did this just to point out that there is a lot to learn before experimenting. I sometimes think that scientests invent these brain twisters just to keep their domain exclusive to them and to confuse us.

Which synthetic is best for your Harley?

Suffice it to say, until you know, don’t go boldly where many disaster prone Harley riders have gone before. As a generalization, choose a 20W50 name brand detergent synthetic that is designed for an air-cooled engine. Use synthetics only after the engine has been broken in. Break ins require fossil oils. First, let’s understand what oil is supposed to do in your Harley. It has four basic functions: 1. Cooling – by dissipating and carrying away heat caused by friction of parts moving together and from the heat of combustion 2. Cleaning – by carrying contaminants produced by friction and combustion to the oil filter (yes, it’s hard to do this without a filter) 3. Lubricating – by putting a film of oil between moving parts to reduce friction 4. Sealing – by preventing leakage past seals and rings. A rubber seal cannot keep oil in or out without having a film of oil to assist it. The lubrication of a motor being broken in must be done with a fossil product free of slippery additives. Rings, for example, have to break through the oil film occasionally to scuff the cylinder wall to form mating surfaces that wear in together. If you use either synthetic lubricants or additives, don’t believe everything you hear. Research the product you are considering after you decide what problem you are trying to solve. A detergent additive is required in whatever oil you use in your Harley since combustion forms acids and varnish that are counterproductive to your engine. Detergents dissolve these harmful products, neutralizing them and carrying them away. Other additives are necessary to:
A. Maintain a high film strength — the ability of oil to remain between two parts such as a bearing surface under great pressure. This alone is a good reason to buy a top-quality lubricant. B. Control the thickness or viscosity of the oil at different temperatures. Heat will thin out oil and, conversely, cold will thicken it. C. Control foam. As oil is splashed around inside the engine it combines with air bubbles and turns into foam. Foam cannot replace oil as a film between parts and the last time I checked air was not a lubricant. Foam will also cause temperatures to rise and that is the real enemy since it increases the rate of oxidation. D. Prevent oxidation. That’s when oil combines with oxygen, picking up water (condensation), rust (oxidation of metal), acids and other byproducts of combustion. It’s a dirty world in there. E. Dispersants . Used to help prevent sludge formation by dispersing contaminants and keeping them in suspension. F. Alkalinity. This helps neutralize acids formed in the oil by combustion and chemical reactions. G. Anti-wear agents. These additives reduce friction between mating surfaces. H. Pour Point Depressants. Got me how they came up with this name. This keeps the oil fluid at low temperatures by preventing wax crystals from forming.
At this point, I should mention that detergents are doing their job when the oil gets dirty quickly. I often get complaints that the oil I sell dirties fast. That’s right, it is only doing its job more effectively. When observing the accompanying oxidation rate chart, it will become readily apparent to the reader that heat is the enemy and must be controlled. With heat comes oxidation of the oil and the only cure for this is to change the oil. When extreme overheating situations caused by improper tuning or a brutally hot summer day exist, oxidation is rampant, so change your oil more frequently.An oil temperature gauge in your oil tank or a cylinder temperature indicator running off the head is a good idea particularly if you live in or travel through hot areas. The cylinder head gauge is more accurate than the oil tank one since it hasn’t had as much time to cool. Add 10 percent onto the oil tank reading to get a better indication of engine temperature.For a fossil oil which comes out of the ground, 2500 Fahrenheit is the figure to remember and for synthetics which are man made, allow for around 300 0 before you get worried about oxidation. As long as sustained operating temperatures don’t go above the 250 0 F. level, everything is “cool” so to speak. However please note that there is something else seriously wrong if a reading of 300 0 F. is ever indicated even though oxidation will be curtailed with a synthetic. The reader can now see a major reason that synthetic oils are superior for severe operating conditions. An oil cooler becomes prudent at or near these levels and may be required for a variety of reasons or causes.Normal operating temperatures for a Harley that is not being lugged; (low speed in a high gear), is properly tuned and is not being abused; (riding in a slow parade with a new motor, i.e. Sturgis), doesn’t have air restrictions; (like leg shields and fairing on a fully loaded FLHT), has the proper viscosity oil in the engine or isn’t stroked, will be somewhere between 170 0 and 230 degrees Fahrenheit. So you see, there are a lot of things that can cause oil temperature to rise and heat is the big problem. As the accompanying chart indicates, the oil oxidation rate increases explosively above 250 degrees for fossil oil like that recommended by Harley. At 270 degrees, a mere 20 degrees above the 250-degree limit, the oxidation rate doubles, thereby reducing the life of the oil by half. Sustained riding at over 300 degrees reduces oil life by 80 percent. Now don’t flip out if the temperature rises above these figures for a short period of time, but change the oil if you’re in doubt. You can observe manufacturers’ recommended oil change mileage if normal temperatures are consistent, but change more often when operating in severe conditions. Remember that unrestricted airflow is the other coolant that allows oil to disperse engine heat through the cooling fins. When extreme overheating situations exist, oxidation is rampant. The only cure for oxidation is changing the oil. Extreme heat indicates the need to change your oil more frequently. Any API rated (read it on the container) oil that is API SG or SH will have the proper additives for your motorcycle and the same rating of 20W-50 (again on the can) will give you the right viscosity.

Reading the Oil Can

Yeah. Here I go again. Like tires where all the information is molded into the sidewalks, oil containers, (except Harley which likes to keep it’s oil a big mystery for marketing reasons), have all the info you need to make an educated decision on whether it is appropriate for your motorcycle’s needs. API…oil classification Originally, oil was a simple product so a classification system was not required. As engines became more sophisticated and engineers constantly improved the qualities of oil a two-letter system evolved with the API, (American Petroleum Institute, which designates the service conditions under which the engine operates. There are two basic categories: S oils for spark ignition gasoline engines like Harley and C oils for compression ignition diesel engines like the 18 wheelers that blow you around on the highways. An oil meeting API standards has a round white donut shaped logo split in two halves on the container. The upper half says API Service followed by two letters. S followed by another for a gas engine like Harley. SA means it is straight petroleum, which is not suitable for our purposes. SB oils were used from 1933 to around 1964. SC introduced in 1964 was used to 1967 while SD was from ’68 to ’71, SE from ’72 to ’79, SF from ’80 to ’88, SG from ’89 to ’93, SH in 1994 and ’95 and finally SJ from 1996 to present. If a dual set of letters appear such as SG/CD, the oil may be used for both gasoline and diesel engines. Now which oils are ok for your Hog? SH or SG are the best followed by SF or SE in a pinch. The lower grades of SD and down are better than nothing but not desirable for a four-stroke motorcycle engine. ILSAC…oil quality If there is a starburst by the API logo, it means that ILSAC, (International Lubricant Standardization Approval Committee), standards have been met. This indicates that the oil has passed more stringent tests involving fuel efficiency and lower oil volatility, (evaporation), which helps decrease oil consumption and benefits emissions systems. Flow properties, water tolerance and the reduction of phosphorus in the oil have also met higher standards. Increasing phosphorus levels increases oil lubricity, which is good. It also hurts catalytic converters, which I’m supposed to say is bad but as a Harley rider it doesn’t really revolve my world. This reduction of phosphorous is a major factor in the latest SJ oils, which Harley doesn’t recommend. More on this later. SAE…oil thickness Inside the API donut on the label is the SAE, (Society of Automotive Engineers), rating which indicates the oil’s viscosity or ability to flow. The SAE rating may also appear elsewhere on the can or bottle. This numbering system identifies the thickness of the oil—the larger the number, the thicker the oil. For instance 70-wt. oil is thicker and will pour slower than a 60 or 50-wt. oil. Straight grade engine oil also thickens when sitting in cold weather causing resistance to the engine turning over while starting which also helps drain the battery. After the engine heats up to full operating temperature, the oil thins, losing some of its film strength. Another reason to use synthetics becomes evident here since they flow more readily at lower temperatures allowing parts to get lubricated sooner. To also help this flow problem, multi-viscosity or multi-grade oil was developed. It operates with the characteristics of light oil when cold to allow easier starting and more immediate flow. Then, when the engine reaches operating temperatures, it serves as thicker oil to provide adequate film strength and protection. Therefore multi-grade oil has the advantages of both high and low viscosity oils. SAE 20W50 is used in all Evo Harleys giving the benefits of both a cold situation 20-wt. oil and an operating temperature 50 wt. Pre-Evos use SAE40 for cold weather, SAE50 for warm weather and SAE60 for hotter conditions. In early manuals when Harley was even more intent in confusing everyone, the Factory’s designations were grade 58, (SAE40); 75, (SAE50) and 105, (SAE60). Later manuals exacerbated this situation by designating their packaged product supplied by major refineries as special light, (SAE40), heavy, (SAE50) and extra heavy which of course is the 60 wt. Except for Harley, almost every vehicle manufacturer in the world follows the API, ILSAC and SAE ratings, as do the oil refiners and includes the designations on their containers. Harley is special in our hearts but in our minds we must realize they haven’t reinvented the air-cooled engine and therefore require specially formulated for Harley only fluids. Harley doesn’t make its own oil. It puts out tenders with the specifications it wants and the major oil refineries bid for the job. The winner packages it in Harley containers. This is not to say the best quality fluids on the market shouldn’t be used because a top-graded oil like API SH is very much superior to discount oils found in Bargain Benny’s basement. I used to preach about buying the most advanced oil for our Hogs but it is time to take a step back. This is not necessarily true anymore. Recommending the most advanced classified oil used to be the best advice I could give. The newest one is “SJ” while the previous designation is “SH”. It is no longer prudent to use “SJ” since it is designed for a water-cooled engine while your Harley is obviously air-cooled. The “SH” rated oil is more appropriate.


Water cooled engines are more efficient because operating temperatures are controlled by the constant cooling fluids that dissipate their heat through a radiator while air might be cool or it might be hot plus you may be idling in rush hour traffic or riding at highway speed. Water-cooled engines typically operate at less than 200 degrees F. while your Harley is over 200 degrees. Harley recommends that if their own oil or a SH oil, (which Harley oil basically is comprised of), is not available that an oil certified for diesel engines be temporarily used. The preferred API rated C diesel oils are in descending order of preference is; 20W50, 15W40 and 10w40. Use these only in a pinch…but they will work. One thing is for sure though and that is the development of oils are undergoing radical development

The War

There is a war going on out there that you the consumer don’t hear about. It’s between major vehicle producers and the oil companies. The reason for this ongoing dispute is complying with ever-stringent emissions controls. I know that I go on about this a lot but if you think about it, the way your Harley or any other vehicle is going to look or be built is totally dependent on the amount of allowable noise and exhaust pollution in the future. So, what’s the fight about? Well, the manufacturers want the oil companies to develop costly formulation changes in the oil to reduce emissions so that the manufacturers don’t have to make expensive design changes to improve fuel economy and emissions controls. For example one big fight is the amount of sulfur in gas. The manufacturers want the oil companies to reduce the content so the acid rain causing pollutants are reduced helping the vehicle people meet their government guidelines. No way, say the gas producers. That costs us too much money. The truth is that both sides will have to join forces sooner rather than later to meet zero standards in the next decade. They better do a good job because battery and fuel cell technology is being developed rapidly. I, for one do not want my pushrod operated Harley engine being replaced by a battery or a rectangular fuel cell that produces drinking water instead of exhaust gases. In any case, the reason I am going on about this is that oil used to stay basically the same for years but these days the black gold is going through ongoing dramatic changes.

What Oils Should You Use?

Theoretically, I know it is safe to use a 20W50 multi-grade in pre-Evos like Shovels and Ironhead XL’s. Practically, I can’t bring myself to do it on my own bikes but I also realize this is a prejudice that has been ingrained in me since day one. I stick with straight grades on my older bikes and run 20W50 in my Evos. If your Evo smokes on a real hot day, Harley says it is ok to run a straight 50 wt. but to me that is an indication that an oil cooler is required. An alternative to an oil cooler is switching to synthetics in extremely hot climates which is also a good idea with winter riding in Northern climates. I personally use fossil oils as opposed to synthetics knowing full well that the synthetics are superior after break-in has been achieved. There is nothing wrong with the fossil oils for your Harley. In fact The Factory recommends them.
Read more about the Great Harley Oil Debate featured in a previous article of American Iron Magazine
If I ever thought I was going to keep a Harley for life instead of changing every year, then, I would switch to synthetics and view them as a long-term investment. There are many excellent oils on the market and just because I don’t mention a particular oil here it doesn’t mean that it is no good. I am only mentioning examples of name brand oils that I would use in my own bikes. If I’m stuck somewhere and need to fill up, I read the can’s information and make an informed decision, just as you will be able to after absorbing this two-part article. First, though, a word of caution. Do not mix synthetics with fossil oils if the tank requires topping up. If switching from a fossil to a synthetic or vice versa do a complete oil change. The residue left by one when switching will have a negligible effect and won’t harm anything. The best fossil oil in the world comes from Pennsylvania crude. It is as close to pure as can be found especially compared with Canada’s tar sands or Texas tars crude. Middle East oil is in the same boat and has to be refined extensively before gaining any semblance of oil that you and I are familiar with. Not that this is a big deal since technology in refining is advanced. What oil do I use? Kendall GT1 from Pennsylvania is a favorite as is any top of the line API SH oil from this State. CCI’s Rev Tech, Nempco’s Twin Power, Silkolene and of course Harley are all excellent oils for your Beast. For synthetics, Belray and Amsoil are two of many good examples. Semi-synthetics are specially formulated combination fossil and synthetic oils that also may be used. Leave the mixing to the oil companies and as I mentioned above don’t attempt this procedure yourself. Harley uses this type in their trannie fluids.

How Often Should You Change Your Oil?

Check your manual for the recommended oil change interval. Use this mileage figure as the maximum you will ever go without replenishing your engine’s lifeblood. A major reason to change oil is that the additives that extend engine life are gradually depleted with normal riding and depleted rapidly with adverse conditions. For example the detergent additives that are very necessary for your Harley suspend dirt and crud particles in the oil to be removed by the filter. As the detergent is depleted, the particles are deposited inside the engine and form sludge. When sludge is found while rebuilding an engine, this is an indicator that the owner hasn’t been changing fluids often enough over a long period of time. Most mechanics would agree that the oil couldn’t be changed too frequently to ensure the longest engine life possible. No need to get anal, though. Every couple of hundred miles would be a waste of money but cutting the Factory’s recommendations in half is a time-honored tradition followed by many. During break-in, I change my oil after 50 miles and every 250 miles up to 1500 miles when the engine will be broken in. Leaded gas despite its good points is destructive in other ways. It causes dirt and corrosion at a rapid pace wearing out mufflers and spark plugs. More to the point it also dirties the oil, breaks it down and corrodes internal parts when given the chance. Unleaded gas is much better from this point of view. It is obvious that Harleys using leaded gas should change their oil more frequently than those using unleaded. Let’s apply a little common sense after analyzing particular riding habits. This type of thinking will allow each individual to determine whether more frequent changes are truly necessary. The combustion process creates a dirty world hidden by a veneer of sparkling chrome. Fresh oil is immediately attacked from all sides by pollutants, heat and condensation to name a few of the enemies. Extreme heat from either internal or external sources is the BIG destroyer. External means operation at temperatures in excess of 30 degrees Celsius in areas like the U.S. South during summer months. Internal denotes excessive temperatures due to improper ignition timing or restricting the normal cooling airflow around the engine fins. As stated numerous times, heat causes oxidation of the oil, which destroys it’s lubricating properties. First rule is to change the oil whenever excessive heat is present or suspected. Better safe than sorry. Other conditions to be aware of which would indicate more frequent oil changes are;
  • dusty roads,
  • trailer towing,
  • long hours of high speed touring,
  • riding on and around sand,
  • exposure to salt air,
  • extensive idling,
  • lots of short trips,
  • riding in rush hour traffic on hot summer days.
Oh yeah, I almost forgot, keep the oil filled up. Even being down a half-quart will raise the oil temperature and you know what that means. Contrast these type of riding conditions with moderate speeds on an open highway on a cool Fall day and you can see the need for oil change intervals tailored to specific conditions. The average interval suggested by the manual may not be appropriate for your riding style or when mitigating circumstances occur beyond control. When a customer tells me that they don’t ride much and when they do, it only involves short trips to the local watering hole, I have to explain why this type of riding can be injurious to the engine if the oil is not changed more frequently. The customer is quite right to argue logically that fewer miles indicate the oil is still functioning at 100%. However, logic is not always right. Consider this! With this type of riding, neither the engine nor the oil reaches normal operating temperatures. The higher temperatures are required to boil off the condensation and unburned byproducts from the combustion process. Therefore, think through your riding habits as they relate to the maintenance of your Harley. Lubricating oil and grease is the lifeblood of your Harley and are only to be ignored or treated casually at the expense of your wallet and the detriment of your ride.

Article courtesy of Donny Smith of Heavy Duty Cycles
The above article expresses the opinions and views solely of Donny Petersen. They are not intended in place of or to diagnose or resolve any issue not assessed by a qualified technician. Donny Petersen and Heavy Duty Cycles Limited does not assume and expressly disclaims any liability with respect to the use of, or for damages resulting from the use of any information, advice or recommendations within. Reference to any product, process, publication, service, or offering of any third party by trade name, manufacturer or otherwise does not constitute or imply the endorsement or recommendation of such by Donny Petersen, Harley-Davidson, Heavy Duty Cycles Limited. E. & O. E. or Harley-Performance.com As submitted to American Iron Magazine.