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synthetic lubricants in an XJ

Discussion in 'XJ Technical Chat' started by Darth_Menace, Dec 30, 2011.

  1. Darth_Menace

    Darth_Menace Member

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    hey guys, I was just wondering your opinion on using synthetics on my xj650. Oil, final drive gear lube and possibly brake fluid (I know the that regular and synthetic brake fluids don't work together) come to mind. Anyone? or does it not matter ont way or another
     
  2. MercuryMan

    MercuryMan Active Member

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    Well it matters to your wallet! Ha. All kidding aside-back when synthetic oil was first introduced there was a lot of chatter about seals swelling and shrinking, even well meaning discussions about how conventional and synthetics won't mix. Throw it all out! It was just that-chatter or at least today it's meaningless.

    Brake fluid is just a hydraulic medium and either would work, but no need to mix them. Under the most extreme conditions more expensive is the way to go. Otherwise it's a push. I use DOT4 and make sure the system is clean and air free.

    For the other two-motor and gear oil. I use synthetics because they have superior wear, same viscosity, and longer life. But fresh conventional will not do you wrong either-it just won't last as long. The fail threshold between the two is never more than 7% according to independent testing. But the fail threshold between the cheapest "crap" and the most expensive available is over 20%. So don't buy the "special" priced stuff.

    So if you can afford it and like to ride hard; spring for the good stuff, otherwise save your $ and don't go over your interval for a change. ALWAYS use motorcycle specific oil only whether synth or conv-Your clutch will thank you.

    Mobil, Castrol, Lucas, Amsoil all test out very well. Friction is your enemy!
     
  3. Darth_Menace

    Darth_Menace Member

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    Ya, my main concern was the information that synthetic oils make these old bikes leak, etc. The concern isnt the money. I use Amsoil in all my vehicles and I live a few minutes from the distribution centre(no shipping) and have a preferred membership so really the Amsoil becomes the same price as the off the shelf regular oil at the store. Amsoil does make a 20w50 motorcycle oil, but no synthetic gear lube for bikes. I am not sure if i will switch the brake fluid as the two can't mix and it would likely be a pain to get all the old stuff out.

    thanks for the help though.

     
  4. MercuryMan

    MercuryMan Active Member

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    It's an old repeated fallacy. Synthetics are not (now) prone to leaking and if for any reason your running hard and pushing the limits they can give you 30+ degrees of protection that a conventional just can't match. Amsoil is slippery stuff. You can find the gear synth from other suppliers. But try to steer clear of the Stealership-hate to say it but they overcharge.

    I use a commercial grade vacuum pump and a vacuum bottle (basically just a bottle with a line in that goes to the bottom and a line out at the top sealed by a two hole rubber stopper) to bleed all my brake systems. It works very nicely. When I first got the XJ550 it took almost a complete bottle of DOT4 to get the fluid to come out clean-and that was after a complete replacement of hoses and cleaning of all the bolts, orifices, etc. My front brake stops WAY too good now!
     
  5. Darth_Menace

    Darth_Menace Member

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    thanks for the help. is gear lube motorcycle specific or just motor oil?
     
  6. MercuryMan

    MercuryMan Active Member

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    Yes motorcycle specific, there's a bunch of varieties. Maxima Hypoid is really good stuff. But let's be honest this stuff is all good. I use Lucas in my cars.
     
  7. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    -Use DoT3 brake fluid as specified by Yamaha, DoT4 is not a good idea in these bikes.

    -Synthetic and semi-synthetic oils, as long as motorcyle specific seem to be fine (so far.) Synthetic AUTOMOBILE oil, or ANY car oil for that matter, is no longer a good idea due to the changes in oil specs. If you notice any starter-clutch misbehavior, switch back to conventional oil.

    -The gear lube (for the final drive) does NOT need to be motorcycle-specific; just the proper stuff again, as recommended by Yamaha.
     
  8. tskaz

    tskaz Active Member

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    I use Shell Rotella 80-90w oil in my final drive.

    Going to switch over to a synthetic in the spring though.
     
  9. mtnbikecrazy55

    mtnbikecrazy55 Active Member

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    i've heard that synthetic oils can produce some not so good results with leaking, not sure why though.
     
  10. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    I think that's more of an "urban legend" than anything else.
     
  11. xjazz

    xjazz Member

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    OK, so I've put Mobil 1 synth non-motorcycle specific oil in two of my bikes, and did not notice any clutch slip. Am I doing any harm to the bike by doing that?
     
  12. mtnbikecrazy55

    mtnbikecrazy55 Active Member

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    hmm. i'll go dig through my history, it was only like a week or so ago when i thought i read that. but take fitz's word over mine, if he says its all good, then its all good lol.

    i was curious though, why dot 3 in the brake lines?

    wouldn't dot 4 or 5 be better because it has a higher boiling point? even if it doesn't get that hot anyway? since when could you overkill on brake fluid?
     
  13. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Only time will tell. We've had a number of members report starter clutch slippage with synthetic/automotive oil.

    DoT4 brake fluid holds moisture that can cause corrosion; it's fine for racing applications but for long-term use in a street bike, there're reasons they recommend DoT3.
     
  14. maz43

    maz43 Member

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    I tried some Castrol power 4T synthetic and immediately had some starter clutch slippage.
    Switching back to regular 4T solved the issue.

    Maz
     
  15. MiCarl

    MiCarl Active Member

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    Hey Fitz, I need to disagree with you. Both DOT3 and DOT4 absorb moisture. Both turn dark as they do and should be changed (2 years max). They're fully compatible with each other. DOT4 has a slightly higher boiling point.

    Some of the stuff about synthetics:

    Back in the way old days seals and gaskets did not have long lives. Engine sludge often built up on the inside of the engine and acted as an additional barrier to leakage. They early synthetic oils tended to be very high detergent and would remove the sludge. So synthetics weren't ruining seals and gaskets, the detergents in them were removing the dirt that plugged the leaks.

    I have yet to see any sludge in a motorcycle engine, even a water cooled one. I think they run too hot for sludge to condense out. I also suspect that all oils are higher detergent than they were in the old days.

    Finally, all modern brake fluid is synthetic. It's made in a factory, not pumped from the ground. Whether the can says synthetic or not is a function of the marketing department. The only non synthetic brake fluid (mineral oil) was done away with before Fitz, Rick and I were eating solid food - a very long time.
     
  16. mikeames

    mikeames Member

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    I definitely agree with this part as it totally makes sense, however I read a report a few years ago on the net (so it has to be true, and I don't remember the source) that stated that one of the reasons synthetic oils tended to leak had to do with molecule size.
    His theory being that with synthetic all of the molecules would be of the same (or very close to the same) size (sort of medium)...where as with conventional motor oil the molecules vary greatly in size.
    The idea being that while the larger molecules in conventional oil would fill the supposedly inherent gaps in gaskets and seals (of older equipment) and as such keeping the smaller molecules from leaking out. Synthetic oils having only one size molecule allows those molecules smaller than those inherent gaps in gaskets and seals to leak out more than conventional oil.
    When posed with the issue that most newer cars are using synthetic only his response was, yes they do, and they also have much better gaskets and seals without all those inherent gaps...
    Interesting thought huh...
     

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