Wed May 21 18:11:23 1997 - Message No. 870
From: "Robert Rowe"

Subject: Re: Yet another question about motor oils


Sorry Pierre, I sent this one privately rather than posting to the list
!

Pierre DEBRAS wrote, presumably before I posted my last on oils :

> as far as I know,
>
> - nobody has been able to explain difference between car/bike oil.

There are a number of differences, including those I already mentioned
which effect the gearboxes on our Bikes when using API SH oils.

Car oils are far more of a compromise than Bike Oils, you don't get many

Turbo Charged bikes for example but Diesel Turbo Charged cars are common

today, therefore car oil has addatives which suit engines such as this.
Okay whilst there are specialist Diesel Turbo Oils about, the standards
published by the various car manufacturers for the types of oil that can

be poured into your car engine, still allows the Car Dealership to put
Castrol GTX in your engine and stay within the manufacturers guidelines.

So as there aren't many/any Turbo Diesel Bikes about, the Oil
manufacturers don't have to put the addatives into the oil to allow for
that type of engine. Addatives that suit one type of engine may turn up
as a deposit in another type of engine, the end result being lowered
reliability.

The same is true in a number of areas regarding addatives, e.g. Bike
oils have different anti frothing agents as the oil pumps on bikes have
to work over a greater speed range.

Other advantages of using a dedicated Bike Oil, over a Car Oil are :

1. Most Motorcycles run hotter than a car, especially sports bikes, and
therefore as the oil does most of the engines cooling, it is important
that the oil you use is the right grade to remove the heat.
2. Unit Construction Gearboxes are hard on engine oil so it is important

to have the right oil so that your gearbox doesn't destroy it.
3. Increasingly, it is what the manufacturuer recommends, particullarly
in the engines of highly stressed sports bikes.

Finally, as I've mentioned "unit" construction gearboxes ( i.e. combined

crankcase and gearbox casing ), I though I should mention that I
wouldn't want to add 10Kg, to my Bike's weight by having a seperate
gearbox, as one well known car manufacturer does on its two wheeled
cars.

Yours

Rob



|------------------------------------------------------|
| This mail was posted on the Africa Twin Mailing List |
|      More info at: http://home.pages.de/~atic/       |
|------------------------------------------------------|

dipper@normans.isd.uni-stuttgart.de