Jim writes:
> 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.
Enough with the rhetoric. The SJ vs SG/SH oil debate could go on
forever if allowed to remain in the realm of theory. As a
practical matter there are two considerations you should be
concerned about relative to the changes to the additive packs in
SJ oil: does your machine have a catalytic converter that must be
kept functioning to meet regulations? and is your engine a
plain-bearing, high-rpm/high-load design? If you can answer "no"
to those to questions, it probably doesn't matter whether you use
SJ oil or not, provided that your choice of viscosity range is
proper and oil changes occur every 3,000 ~ 5,000 miles. With all
due respect, folx, KLR 650's don't fall in either category.
SJ oils have reduced levels of the additive ZDDP. ZDDP (Zinc
DialkylDithioPhosphate) contains elements that "poison" catalytic
converters when deposited via oil burning; since automotive
catalysts *must* remain functional past 100K miles and must pass
annual inspections, this additive was a problem for emission
system designers concerned with regulatory compliance and changes
to the oil additive package were the result. FWIW, at the same
time, CAFE (Corporate Average Fuel Economy) requirements have
driven engineers to seek power "overhead" reductions where they
can find them - oil system pumping losses, for example. Hence, SJ
oils typically are coming in lower viz ranges - 10W30 or 5W20,
for example, and 0W-20 is on the horizon. The reason ZDDP (and by
extension, certain levels of zinc) is important to motorcyclists
is in extreme load conditions such as those on rod bearings or
cam/tappet surfaces at extreme high rpms (such as your CBR F3/F4,
Yamaha R6, etc.), or in big, heavy, air/oil-cooled engines such
as BMW's R1100GS. Zinc is the last thing standing between metal
to metal contact when oil films break down, and for that reason
is important if you regularly stress your motor to its mechanical
and lubrication limits.
Now to the point: KLR 650's are neither high-revving nor
air-cooled, nor do they have a catalyst. This motor makes about
40 horsepower (don't get yer noses outta joint, now!) on a good
day and typically never sees its own rather modest red-line. It's
water-cooled and made of good materials by engineers who also
design ZX-11's and the like and know what they're doing. If SJ
oil were commonly available in 20W50, I wouldn't hesitate to run
it in mine, but I think the viscosity range so important that I
pay more and buy SG grade to get not only the better additive
package but what I consider the proper viz range.
I think of the oil question this way:
- some oil is better than no oil
- clean oil is better than dirty oil
- the correct viscosity is better than one heavier or lighter
than needed
- SG/SH is better than SJ *for motorcycle applications*
- Teflon, graphite, and snake oil have no place in motor oils;
zinc does
Now back to your regular programming........
Tom Bowman
Atlanta
A14