Based on this information, I am sticking with Castrol Syntec or Mobil1 (whichever is available when I need it) in 20-50 in the enigine and I am switching to 75/80-90 gear oil in my tranny. No more engine oil in my sporties tranny again. This article makes quite a case that engine oil has additives to deal with combustion byproducts that your tranny simply does not need while at the same time testing has shown that wet clutches have better lock up when running in gear oil.

Check it out: http://www.sportster.org/tech/OilandtheHarleyDavidsonMotorcycle.pdf

Yes, this is an excellent paper by Lee.
Many of us on the XL-List sponsored the paper by
paying for the oil analysis.

Even before the paper I used Mobil1 15w-50 in the
engine and Sport-trans in the primary. Although I
have used Syn-3 in the primary once, I went back
to the Sport-trans since it costs less and performs
better in my bike.

Good read, thanks! My work is in fluid analysis, I run a lab at a university that does exactly this sort of thing, though mostly for hydraulic fluids. Some good info in there, though the real story would fill thousands of pages!! I like the author's attitude regarding the subject.

Moderator, can we make this thread a sticky or would that violate the authors rights in some way? Perhaps because we are simply linking to its origin its OK?

BTW, I have just purchased a quart of Mobil1 synthetic 75-90 gear oil and it smells just like Sportrans(very strong odor). I think its safe to say Sportrans is gear oil.

Yes, this is an excellent paper by Lee.
Many of us on the XL-List sponsored the paper by
paying for the oil analysis.

Even before the paper I used Mobil1 15w-50 in the
engine and Sport-trans in the primary. Although I
have used Syn-3 in the primary once, I went back
to the Sport-trans since it costs less and performs
better in my bike.

I did the exact same thing as you. I returned to sport-trans and I feel my tranny is performing better than with syn3. Also changed to Mobile1 15w-50 as well. Very happy.

Excellent Artical... Thanks for posting the link !!

So ... HD oil is good stuff after all (according to the article). That's what's in mine (Syn3). It's pricey, but only has to be changed every 5,000 miles.

Interesting stuff, once my head stopped spinning! Thanks for the link.

Wonderful paper. I second the notion that we make the original post with the link a sticky.

I disagree with the assumption that HD Syn3 is worth the extra money. They don't refine, process or in any way have a hand in the product (in spite of what you may hear). They merely have it packaged in their container, purchase it a jobber rates and mark the hell out of it... just lik everything else they sell.

The following is my own personal opinion and not to be construed as fact:
In the early days of oil refining we only had Pennslvnnia crude. At the time, it was considered to be the best available. Problem was it was paraffin based. That's the sludgy stuff we used to scrape off then heads from time to time. The going advice was to change oil every 2500 miles. Today's oil from the Mid East isn't paraffin based and have a much sweeter (low sulpher) quality. The oil companies were slow in revising their frequency and why not? They sell the stuff. We now see normal Dino oil advertised at 7500 mile frequency intervals. Can synthetic be hardier and les prone to breakdown?

I'm of the opinon that the only real culprits we havve to deal with today are induced water vapor and gas contamination. Without the two offenders, we might be able to literally never change oil, Indeed, when Mobil 1 was first introduced it was touted as just that. "Never change oil again", a statement the oil folks have since recapitulated on. At tis point I'm yet to be convinced that recapitulation isn't anything more than another marketing ploy. My point is this... I still doubt any recommendation given by the oil barons. That's like asking the beef council how often should I include beef in my diet.

Without imperical eveidence, I believe that oil change frequedncy may well depend on factors inclusive of the aforementioned culprits and possibly others. I will appreciate any input on the subject.

There is an exellent article on syn oils in november issue of american iron.

I disagree with the assumption that HD Syn3 is worth the extra money. They don't refine, process or in any way have a hand in the product (in spite of what you may hear). They merely have it packaged in their container, purchase it a jobber rates and mark the hell out of it... just lik everything else they sell.

The following is my own personal opinion and not to be construed as fact:
In the early days of oil refining we only had Pennslvnnia crude. At the time, it was considered to be the best available. Problem was it was paraffin based. That's the sludgy stuff we used to scrape off then heads from time to time. The going advice was to change oil every 2500 miles. Today's oil from the Mid East isn't paraffin based and have a much sweeter (low sulpher) quality. The oil companies were slow in revising their frequency and why not? They sell the stuff. We now see normal Dino oil advertised at 7500 mile frequency intervals. Can synthetic be hardier and les prone to breakdown?

I'm of the opinon that the only real culprits we havve to deal with today are induced water vapor and gas contamination. Without the two offenders, we might be able to literally never change oil, Indeed, when Mobil 1 was first introduced it was touted as just that. "Never change oil again", a statement the oil folks have since recapitulated on. At tis point I'm yet to be convinced that recapitulation isn't anything more than another marketing ploy. My point is this... I still doubt any recommendation given by the oil barons. That's like asking the beef council how often should I include beef in my diet.

Without imperical eveidence, I believe that oil change frequedncy may well depend on factors inclusive of the aforementioned culprits and possibly others. I will appreciate any input on the subject.

In the hydraulics industry, better technology in fluid analysis is making possible condition-based predictive maintanance scheduling. Hydraulic and engine oils are monitored on a schedule and changed when we notice either certain changes in the chemistry or the prescence of particle contamination.

Bottom line Will, you're right - there is NO truth in assigning a number to how long an oil will hold up. I've seen 2 identical machines running identical loads each using resevoirs full of the same hyrdraulic oils - one runs fo 50,000 hours and the other is taken off line after 5K to prevent catastrophic failure.

The 3,000 mile interval is certainly safe. But does that mean that at 3,500 your engine was going to be damaged? or at 5,000? what about 20,000? You have no idea, do you?

I'm surprised AMSOIL isn't in on there test.

I ran Mobil-1 75w-90 last oil change. It has a ver stong order that was noticable even when riding the bike. It also seem to weep is way out, though the drive shaft, I think, as after rding I would have very small droplets on my belt. I switched back to Bel Ray 85w gear saver.

Let me know how your experience goes witht he Mobil-1 75w-90.

Thanks for the great info!!! Since I live nowhere near an HD dealer...or anything else for that matter....it is comforting to know that my '97 is safe with Mobil 1 Syn. in her. Rick

I ran Mobil-1 75w-90 last oil change. It has a very stong odor that was noticable even when riding the bike. It also seemed to weep is way out, though the drive shaft, I think, as after rding I would have very small droplets on my belt. I switched back to Bel Ray 85w gear saver.

Let me know how your experience goes witht he Mobil-1 75w-90.I had exactly the same experience with Mobil 1 75w-90. And it seemed to shift very poorly, too. (When I drained it, it ran out like water . . . perhaps it's too thin for smooth shifting?)

At this point, I've had Syn3, Mobil 1 15w-50, Sportrans, Formula +, and Mobil 1 75w-90 in my '05's transmission. While my research has not been conducted in a controlled lab setting, my subjective experience is that HD Formula + is far and away the best fluid to put in a rubber-mount's transmission. Especially if you install it, run it a while, then change it again to get as close to 100% Formula + as possible.

For me, the matter's settled, the case is closed. I'll experiment no further--I'll run Formula + in my '05's tranny and Mobil 1 15w-50 in its engine. (I noticed an immediate reduction in oil temperature when I switched from Syn3 to Mobil 1.)

I've read this article before. My favorite part is still the section on how oil actually provides more protection later in its life than when it is brand new. Makes me wonder how many people on this forum believe they're babying their bikes by doing oil changes every 2000 mi (or some ridiculous number like that) when in reality they're wasting money and hurting the engine.

I was always under the impression that is was the filter that wore out/clogged long before the oil had exceeded its useful life. Hence BMW's have a special (and expensive) filter that allows them to go 15,000 mi between recommended oil changes.

Cheers,
Luke

I thought I would point out a few things about our bikes. First, with a 3.6 quart fill, we have a significantly higher oil-to-displacement ratio than most cars (my 5.4 expedition holds 6 quarts I believe, so that’s 1.11 ratio compared to our 3 ratio, even better if you have an 883). Also, our filters are bigger than many automotive filters (including the filter on the f-body ls1 motors) that serve engine 2-5 times larger than ours. So going by typical automotive change intervals is not really valid here. As someone pointed out, it’s not that the oil goes bad (although our engines are a bit of a torture test for oils, being air cooled), but that the filter gets clogged with contaminants. When a filter gets clogged it goes into bypass mode and you oil turns into liquid sandpaper (the cheep and easy way to hone your cylinders right :eek: ), but we all know this. So, if your truly worried about oil change intervals, save yourself 40 bucks in oil every 5k and just change the filter every 2.5k. But I argue, with the amount of oil we have and the size of our filters (especially if you get the longer HD filter, which I use and I believe them to be good high quality filters), that a 5k change interval is more than adequate. If you whish to have further protection for you bike, get a oil cooler with a thermostat, it will make you bike run cooler and your oil last longer.
Dan

Mobile I 20W-50 V-Twin Synthetic in the engine (Sporty and BigDog).
Mobile I 20W-50 V-Twin Synthetic primary (BD).
Redline Heavy Shockproof (BD tranny/Sporty primary)

Works good lasts long time!

That oil paper is pretty good. There's another one called the AMSOIL Motorcycle Oils Whitepaper. You can find it by following the 20W-50 link in my signature. You go to the 20W-50 product page and the whitepaper link is there along with another link for recommended oils for Harley applications PDF. The report results are notarized, and the tests included the following:

SAE Viscosity Grade (Initial Viscosity - SAE J300)
Viscosity Index (ASTM D-2270)
Viscosity Shear Stability (ASTM D-6278)
High Temperature / High Shear Viscosity (HT/HS ASTM D-5481)
Zinc Concentration (ppm, ICP)
Wear Protection (4-Ball, ASTM D-4172)
Gear Performance (FZG ASTM D-5182)
Oxidation Stability (TFOUT ASTM D-4742)
Volatility (Evaporation) (ASTM D-5800)
Acid Neutralization and Engine Cleanliness (TBN ASTM D-2896)
Foaming Tendency (ASTM D-892)
Rust Protection (Humidity Cabinet ASTM D-1748)
Wet-Clutch Compatibility (JASO T 904-98, limited review)

AMSOIL isn't always the best test performer, but it is always very good.

I agree with 1337-Sporty about the HD Formula +. I have used several tranny lubes and none works as well as te Formula +. Regarding Synthetic engine oil, I have used Amzoil, Syn3, Mobil 1, and Redline High Performance. I am staying with Redline. The Engine temp. is 10-20 degrees cooler, and my mileage went from 56 average to 61 on a bone stock 05 XL-883. I know Redline has a high moly content, but that's fine in a Harley where engine oil does not also lubricate the clutch.

I also agree with the Formula+ in the tranny/primary. Not scientific, but seems to shift smooter and quieter.

Also went back to the Formula+ in my BT primary, but Mobil 1 75W-90 Synthetic in the transmission.

ok, this article had my complete attention until i got to this statement.

engine wear actually decreases as the oil ages. what this means is that changing the oil frequently actually causes more wear than using more of the lifespan of the oil.


now that statement caused my ears to lay flat to my skull and start me looking a little pig eyed at the at the article. being a mechanic and an amsoil dealer i think that most oil is drained before its time. but the only to be sure is with an oil Analysis. given the quantity's we are dealing with it is cheaper just to dump it and start fresh. wait, wait, according to this dude maybe we should be paying a premium for and using used oil and our engines would last a lot longer. just think we could probably make money selling our used oil to some one whose oil wasn't as used as ours, therefor saving there engine for them. changing the filter is probably disastrous. the only wear caused by changing the oil to soon is to your wallet.

i read this post when it was new and debated until now whether to comment on it. but i think that statement is ludicrous.

Thanks for the article!

peeking out the curtain...dark outside...but...only see leaves on the ground...fall for sure...but no snow yet...not winter yet...too early for oil threads...we've just come out of the which-jets-for-me-season and should still be in the what-seat-is-best season...but definately not oil thread season yet...

;)
:tour

Do you know why the owners manual says to be sure to use oil that is approved for diesel engines?

Detergent agents are in diesel oils, help keep engine clean.

Do you know why the owners manual says to be sure to use oil that is approved for diesel engines?

Are you saying that non diesel oils do not contain detergents?

Some do & some don't, you need to look on the label for the detergent/diesel code CF, CF4, CG4, etc. The label will say something like SAE 20w50 API CG-4/SL. The CG-4 is stating that it is suitable for diesels. The SL is the quality/protection factor of the oil. Example; SA would be the lowest protection and SZ would be the best protection. P.S look for a rating of SL or SM

Are you saying that non diesel oils do not contain detergents?

So I must be the only person running Rev-tech Pure oil? It's not syn, but a hydro-cracked oil refined to be so pure, it ends up clear, and then they throw in a couple of additives. It's made for V-twin engines, and runs great in my 75 XLH......

Great info!
Just a side note on synthetic oil, I work on fighter jet engines for a living, these engines use a MIL-7808 synthetic oil and are subjected to extreme temperatures. The oil is never changed! Since there are no exhaust gasses leaking into the oil like there are on a piston engine the oil stays clean and there is no build-up of sludge and contaminants. The reason oil is changed so often on piston engines isn't because the lubrication properties break down, it is because the cleaning properties of the oil breakdown. Synthetic oil is amazing stuff!

Some do & some don't, you need to look on the label for the detergent/diesel code CF, CF4, CG4, etc. The label will say something like SAE 20w50 API CG-4/SL. The CG-4 is stating that it is suitable for diesels. The SL is the quality/protection factor of the oil. Example; SA would be the lowest protection and SZ would be the best protection. P.S look for a rating of SL or SM

Isn't it best to make sure that the oil used in a motorcycle also has an SG, SH or SJ rating as those oils have high zinc and phosphorus levels which protect the engine better than oils that do not have that rating? Isn't it also true that the plain SL and SM oils with none of the above ratings were reformulated to remove some of the zinc and phosphorus in order to keep them from damaging the catalytic converter in cars? If the oils have SG, SH or SJ ratings plus the SL or SM, they would be OK as well wouldn't they? The SL and SM ratings have nothing to do with increased motor protection as far as I know or am I all washed up in my belief that those ratings aren't necessary or even necessarily beneficial for the oil used in our machines? If my understanding is correct, there is no way that I would use a plain SL or SM automotive oil in my bike if it didn't have any of the earlier SG, SH or SJ ratings. Any comments from an expert would be welcome.

Anytime An Engine Oil Spec (api) Changes To A Higher Letter It Supercedes A Previous Letter
Ie: Sm Is Better Than Sj And Cj Is Better Than Ci And Is Backwards Compatible

The SL and SM ratings have nothing to do with increased motor protection as far as I know or am I all washed up in my belief that those ratings aren't necessary or even necessarily beneficial for the oil used in our machines?

Actually, SL/SM API specification require less wear tolerance, less tolerable foaming, etc. than SG/SJ oil.

Just better, all the way around than the SG/SJ API certifications.

If you have some time take a click over to bobistheoilguy.com. Users post real world oil analysis results for just about anything in the way of internal combustion engines. Greases, transmission fluids, etc. Lots of good reading. They even have virgin oil analysis so you can see the additive package in your particular brand of oil.

Yes, motorcycle-specific and diesel oils have slightly higher zinc/phosporus than automotive oils, but remember, the zinc/phosporus levels are less than ten percent of what they were 30 years ago. Oil chemistry has improved dramatically.... and you don't really need as much of this additive as in years past.

A favorite oil with the metric crowd is Rotella 15w40. It shows excellent oil analysis reports, especially considering that most metric bikes have a shared sump for the engine/transmission/primary. Two bad they don't offer it in a 20w50.

Automotive oil in a Harley crankcase is fine, as long as you're in the correct viscosity range.

Actually, SL/SM API specification require less wear tolerance, less tolerable foaming, etc. than SG/SJ oil.

Just better, all the way around than the SG/SJ API certifications.

If you have some time take a click over to bobistheoilguy.com. Users post real world oil analysis results for just about anything in the way of internal combustion engines. Greases, transmission fluids, etc. Lots of good reading. They even have virgin oil analysis so you can see the additive package in your particular brand of oil.

Yes, motorcycle-specific and diesel oils have slightly higher zinc/phosporus than automotive oils, but remember, the zinc/phosporus levels are less than ten percent of what they were 30 years ago. Oil chemistry has improved dramatically.... and you don't really need as much of this additive as in years past.

A favorite oil with the metric crowd is Rotella 15w40. It shows excellent oil analysis reports, especially considering that most metric bikes have a shared sump for the engine/transmission/primary. Two bad they don't offer it in a 20w50.

Automotive oil in a Harley crankcase is fine, as long as you're in the correct viscosity range.


I'd qualify your last statement by also following the specific Harley-Davidson Diesel Spec recommendations that are spelled out in the owner's manual. Not just any 15W-40 or 20W-50 automotive oil will meet those requirements. Most 15W-40 likely will as it is generally made for diesels and at least some 20W-50 will but the correct viscosity alone isn't enough.

I agree. I've read bobistheoilguy.com many times over the past few years and he makes some good points that seem generally right on.

I'm curious as to where you got your information from that states that oils meeting SL/SM oil specs require less foaming and less wear tolerance than SG/SJ oil. I'm not saying you're wrong as I'm no expert, rather I'm just curious about the information as I've read that the SL/SM oil was formulated without the zinc just to protect the catalytic converter and the newer designations had nothing to do with increased engine protection. If it did, one would think that motorcycle specific oils would have the newer designations as well. Last time I checked the motorcycle oils that I checked didn't. One manufacturer even explains that the higher zinc content of the older designation offers greater protection.

Don, I got my information on bobistheoilguy.com. I also went out to the web and read the API spec for SG/SJ oil and also for SM and SL.

SL/SM oils still have some amount of zinc/phosporus. Don't quote me, but I believe that the requirement is < 1200 ppm. Just as an example, the virgin oil analysis for, say, Mobil 1 5w30 - there's still 9xx ppm.

Also, the new formulations for SG/SJ are showing less zinc/phosporus. I'm thinking the target is no more that .6 -.8 %

You're right that most motorcycle-specific oils do not show SL/SM but I'm sitting here looking at the label on a bottle of Amsoil 20w50. Is says API service SL.

Ahhh - but less cam bearing wear for SM oil does not tell the whole story. High spring rates on push-rod engines show increased cam face wear with SM rated oil. This is where the increased levels of ZDDP are beneficial.

Don, I got my information on bobistheoilguy.com. I also went out to the web and read the API spec for SG/SJ oil and also for SM and SL.

SL/SM oils still have some amount of zinc/phosporus. Don't quote me, but I believe that the requirement is < 1200 ppm. Just as an example, the virgin oil analysis for, say, Mobil 1 5w30 - there's still 9xx ppm.

Also, the new formulations for SG/SJ are showing less zinc/phosporus. I'm thinking the target is no more that .6 -.8 %

You're right that most motorcycle-specific oils do not show SL/SM but I'm sitting here looking at the label on a bottle of Amsoil 20w50. Is says API service SL.

Ahhh - but less cam bearing wear for SM oil does not tell the whole story. High spring rates on push-rod engines show increased cam face wear with SM rated oil. This is where the increased levels of ZDDP are beneficial.


Thanks! I'll read further. That cam wear has been a concern of mine regarding the latest spec oils.

Anytime An Engine Oil Spec (api) Changes To A Higher Letter It Supercedes A Previous Letter
Ie: Sm Is Better Than Sj And Cj Is Better Than Ci And Is Backwards Compatible

If my information is correct, later specifications aren't always necessarily better, just newer. For instance, if my memory is correct the SJ oil has no different specification than the older SH oil spec. other than the manufacturer had to agree to off the retail shelf testing rather than providing a perfect sample to be tested. It just assured that the production oil would pass muster. I think it was similar with the SL oil. If my memory is correct (may not be right on which spec, SJ SH SL?) SL spec. oil wasn't supposed to be better for anything other than the catalytic converter due to it's lower zinc content. :)

When I had to decide what oil to use in my Ford Powerstroke Diesel I searched all over the internet for information and had oil analyses performed by the local Caterpillar dealership's lab.

When all was said and done, and based on the reccomendation of the oil analysis lab, I ended up sticking with the synthetic blend oil that Ford markets and recommends for that engine and changing it at the recommended 5000 mile frequency along with the filter they recommend. I could very likely stretch the oil change mileage on that truck to 7500+ miles by getting the oil analyzed often (some folks have stretched oil changes out to 20K miles and farther.)

For my Sportster, I'll probably switch to the H-D synthetic oil at the 1000 mile service in a couple weeks. (I changed the oil and filter at 500 miles like I always do on a new engine.) To avoid any crazy arguments should the worst happen, I'll use the H-D recommened oil filter.

Maybe that seems a bit sheep-like but, you know, if I have a problem I expect both Ford and H-D will stand behind me if I do what they are recommending.

The only time I ever seriously trashed an engine was when I decided that I new more about oil than the manufacturer did and used something I shouldn't have. I've tried to learn from that, rather expensive, experience.