Rotax 4 stroke oils

[Ralph Baker]

Hello Ian,
The oil issue is more complex than any of us want it to be. Here is my 2
cents based on many years of motorcycling and oil seminars at rallies.
This is US info, I'm not sure what other countries require. The oil cans
have a circular symbol with (presently) "SJ" in it. This is the latest
formulation and has less calcium and phosphorus in the additive package to
protect catalytic converters. In earlier packages they were to provide
last ditch lubrication. BMW specifically prohibits the "SJ" formulation
for their motorcycles. In addition the oils are formulated to improve fuel
mileage due to CAFE requirements. The BMW motorcycle synthetic 15w-50 oil
that we use is labeled API SH and so in my opinion is a "better" oil than
the later SJ.
Sure they wan to sell their oils and yes, it is expensive. You may be able
to find another brand that still carries the SH or earlier rating. This is
all complicated by the API standards not applying to 20W-50 multigrades.
BMW has a separate gear case but the engines routinely turn 8500 RPM and
their oils do have an anti foaming additive.

I do agree with Bob that breakin should be with a conventional oil, not
synthetic. Only when oil consumption has stabilized should synthetics be
used. They offer more stable viscosity over temperature and generally a
quicker pump up time on starts. As a final note, while it is not a good
practice synthetic and conventional oils of any mnufacturer can be mixed to
get you home without particular concern

Of course none of the the above applies to what Bob P lovingly calls Genus
Lycosaurus.
Ralph Baker
Elite serial 611E



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[allsure]

G'day Bruce and Ralph

Thanks for your responses regarding the oil.

As I said in my reply to Bob, I am still just a little confused about it
all.

Some fellow flyers here have used a standard oil to break in, and then
switched to
synthetic oils later in the engine life. I think that's what I will do
initially.

The costs of full synthetic oils here are quite significant, so I guess that
also
cost has to be factored in somewhere in the decision.

What I will do is talk with a local dealer and discuss the issues raised by
Ralph.
That should make for some interesting discussion!

Regards

Ian Donaldson





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