oils and lubes

[Skip Faulkner]

 

Skip, Thanks for your reply.  As a former m/c mechanic & one who has worked on bikes for 30+ years, I understand better than most the importance of proper m/c maintenance.  I tend to keep my bikes a long time and I want to maximize reliability and engine life.  I found that Castrol synthetic blend (auto: 20W-50) noticeably improved my KLR's shifting, it no longer is in the same category as my R90/6 beemer, but there is still room for improvement.  A while back I posted a suggestion about "pre-loading" the shifter before dis-engaging the clutch to help eliminate the balky shifting & false neutrals. Cost is always a consideration in every aspect of what we do.  I don't mind paying $2-4 (US$) per quart of oil, but hesitate to pay $8-11 & still do frequent oil changes.  I don't want to be penny-wise & pound-foolish, but until I've seen proof that the SJ rated oils WILL shorten my engine life, I can't justify the higher cost.  If the SJ oils would DEFINITELY cause the wet clutch to slip, then I would have no choice but to pay the piper for the high-priced spread. I have researched the SJ vs SG matter a bit, & my lay conclusion is that the clutch slippage problem is related to "hard" riding, especially with hyper-bikes.  The fact that our water-cooled KLRs are not subjected to the same operating temperature extremes as an air-cooled engine, leads me to believe that engine life will not be compromised by using a good quality SJ rated oil.  Clutch slippage however ...

I am going to try SJ rated Mobil 1,  15W-50 automotive oil, hopefully to further improve my "character-enabled" BMW-like tranny.  Any further info on this subject would be greatly appreciated.

Professor       A9        Federal Way, Wa. [USA]

ps: how come your messages have such tiny type?  By next year I'll need a microscope     attachment for my reading glasses!

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Jim,

  The reason the automotive SJ oils are giving the bike manufacturers` such fits AND the reason the SJ oils are causing some clutch slippage ( doesn`t matter if water or air cooled) is because of the friction modifiers added to the oil to replace the reduced amounts of zinc and phosphorus. The friction modifiers are what cause the clutch slippage. The p. engineer I talked to today (Shell) said that the situation is less of a concern in dry sump clutches, therefore using automotive SJ in the engines with dry sump clutches is not as much a factor.

    Besides Shell, I also talked to a Citgo engineer today also and will post tomorrow, what they told me along with some recommendations they gave me, as well as what they are doing to address this SJ situation, as far as bikes are concerned. I need to get home.

 

Skip