Auto Oil
Auto Oil
mark said:
The reason given for not using auto oil is that since these bikes run a "wet" clutch, supposedly there is an increased chance of clutch slippage.
Whether or not that's true is open to debate. I've always used it and never had a problem But automotive oil won't ruin your engine or anything like that.
Make sure you can see oil in the glass before you start it, even if you have to change it right away just to make sure that there is SOME oil in there! 10-40 is the factory recommendation, but some use other viscosities.
I received the following information from Castrol:
"Castrol does not recommend using automotive oils in motorcycles. The
Reason? In 1996 the American Petroleum Institute (API) upgraded the
performance standards of automotive oil from SG to SJ (currently SM).
This upgrade impacted the friction modifiers and zinc and phosphorus
levels, to address the fuel economy, catalytic converter and pollution
issues of passenger car owners. For motorcycles, the additional
friction modifiers can affect wet clutch performance, and motorcycle
engines appreciate a higher level of the anti-wear ingredients of zinc
and phosphorus.
We have formulated our line of Castrol Motorcycle oils to be API SG.
This allows us to optimize the formula specifically for motorcycles
without being constrained by the specification demands for passenger car
engines, which our passenger car oil must meet. All Castrol Motorcycle
oils have low volatility to reduce the effects of oil evaporation, and
they can be up to 50% lower than many API SM/SL/SJ passenger car
engine oils. API SJ engine oils have a minimal shear stability
requirement; therefore, some types may lose their viscosity more quickly
when used in a motorcycle, due to the stresses of these bike engines.
The Castrol motorcycle line includes oil for 2 stroke, 4 stroke and
V-Twin oils with a wide variety of viscosity ranges and oil types,
including mineral, synthetic blend and fully synthetic formulations.
This variety offers superior performance for all motorcycle rider
demands and every type of riding condition.
For an air cooled motorcycle, we recommend a V-Twin formulation-
Castrol V-Twin, and Castrol ActEvo V-twin
For the liquid-cooled, either V-twin or 4 stroke would be appropriate,
and your choice should be based on the viscosity requirements of the
motorcycle - Castrol ActEvo, Castrol GPS, and Castrol R4 Superbike"