What wrong with SYN3 in all 3

Discussion in 'Oil' started by oct1949, Mar 21, 2008.

  1. oct1949

    oct1949 Member

    I've had 9 diff bikes in my life, only 2 Harleys. The 1st Harley was a 69 xlch back in the 70's, which was nothing but problems, now the 07 Heritage with 9.4K on it is no question the best I've owned...
    I have read and read about all the different oils and their claims that each one of their oils are the best....
    I have also found that every HD item I have bought so far has been top quality and completly happy with them.
    So my question is not which oil in what hole is better than the others.
    My question is with Harley knowing what should be the best oil in a harley (WHAT IS WRONG) with the Syn3 oil which Harley offers and the dealer recommends in all 3 holes??? :wall
  2. HarleyHarry

    HarleyHarry Banned

    I'm absolutely with you Hobbit. If it's good for one thing it cannot be for the other. The demands on oil are different behind the three plugs. But what I can not understand is how can HD recommend the oil in all three holes and offer an extended warranty if it wasn't sure that no damage can be done?
    They can't be stupid.....or can they?
  3. kemo

    kemo R.I.P

    I also have to ask what is wrong with running the same oil in trans, primary and engine.

    The Japs run the same oil in their bikes, in fact they don't even seperate the engine from trans or clutch, they build one case to house everything.
  4. Solitaree1

    Solitaree1 Banned

    My two cents...
    I don't think there is anything "wrong" with it, just that there are other options that are better for you, better for your bike.
  5. oct1949

    oct1949 Member

    Thanks to Hobbit and all others for the answers in this thread. The thread that Hobbit gave us to follow is probably the most honest oil test that will answer a lot of questions which will help us Harley riders choose which oil
    to use.
    So far it looks like Mobil 1 is the oil for motor, still not sure on primary? and even though the test said a 75-90w in the trans it didnt state what brand is being used in the test or I missed it....
    As stated eariler I have an 07 heritage, and the 1st K used oils put in new bike, 1K - 5K I installed syn3 as @ dealership;; and at the 5K I also had syn put in as per dealership..
    Now spring 08, 9.4K And ready to ride and also change oil in all three holes I will probably ask for different oils now that I have learned more....
    One question though is so far it looks like Mobil 1 in motor and primary, but what brand transmission oil was used in bike no 4 in test, I am left to think it was also Mobil 75-90w syn gear oil,,,....?????
    Just tring to make a GREAT bike last longer.
    Again thanks for the help,
    Hope you'alll (hillbilly talk) I married one, Ha!!! a Safe, happy and many great Hrs in the saddle....
  6. R. Lewis

    R. Lewis Senior Member Retired Moderators

    Joe --- read somewhere that Citgo is changing their name to Petro-Express.
  7. glider

    glider Veteran Member

    It's an easy way out for the MOCO. It's a motor oil and not a gear lube and isn't a true synthetic also. Use a gear lube in the trans and it will last longer and you will see a difference in shifting too. Why do you think they came out with the Performance + for use in the primary and trans???
    In many cases your warranty will be over by the time the problem shows up.
  8. Electraglidin'

    Electraglidin' Member

    Engine oil is more than capable of lubricating the manual transmission in a motorcycle. The majority of the millions of manual transmissions in cars and light trucks on the road today have dino 10W-30 motor oil (or ATF) in their gearboxes. Many 1-ton light trucks have GCWR's over 20,000 lbs. and easily go 100k+ miles with nothing but 3-4 qts of dino 10W-30 protecting their transmissions. So I find it hard to believe a quart of synthetic 20W-50 can't adequately lubricate the transmission in a sub-1000 lb. motorcycle.

    H-D isn't going to tell you to use something in your transmission (that they provide a warranty on) unless they know it works. Yes, there are cheaper solutions out there that work just as well or better, but to say engine oil can't provide adequate lubrication for the gearbox in a H-D motorcycle is wrong.
    Anyone who disagrees is welcome to post verifiable evidence from knowledgeable and reputable industry sources to the contrary.

    I've been a mechanic for over 30 years and am no Koolaid drinker, but when it comes to deciding the basic question of what is and isn't an adequate lubricant for my powertrain, I'll take the recommendation of the OEM engineers over someone's opinion in an internet forum every time. :s

    Just my .02...
  9. glider

    glider Veteran Member

    I feel that the the MOCO switched from Syn 3 to Performance+ in the trans for a good reason but they will never say why. I have seen blued shifter forks in the harley trans and bearings that went out also that were run on Syn 3 where others were not blued at all using gear lube and no problems with the transmissions at all when run on a gear lube.
    I have also been doing this work about the same length of time as you and can only speak from experience working on bikes.
    Everyone can feel free to run anything they wish in their trans but I'll stick to a gear lube despite what other brands of bikes or cars use, I just feel better about it seeing the results of the other oils first hand. Let's not forget here that most cars are water cooled and can tolerate a bit more abuse before the oils break down or even shear.
    I'm a believer in what I see works and not what I hear or read. If you look at some of the major oil company sites, they all claim to be the best, it stands to reason that this couldn't be true.

    Another thing to consider here is that by the time a trans decides to take a dump, most bikes will be out of the factory warranty and if you didn't buy the extended warranty, you have a big and expensive problem now. Most any trans will live the 2 years of the warranty with just about any slippery substance in there.

    Welcome aboard!
    Last edited: Mar 29, 2008
  10. FBOY

    FBOY New Member

    I've got a new 2008 Fatboy and am doing the research to see what transmission oil I'll change to at my first service. From what I've seen on this site, it sounds like there are a number that are well rated like Spectro and Mobile1. Also, I've seen it stated that both 75/90 or 75/140 are acceptable. Under what circumstances would one be better than the other? Thanks