Dec 1, 2006
I was talking to some guys at a cycle shop today and they specialize in KTM and any suspension, any way some guys that know a heck of a lot more than I do about bikes, I think. They said I am waisting my money on synthetic oil as long as I change it every other ride which I do along with my air filter. Ok I belive him and I will probably stop buying synthetic but he said he runs Rotella 15w40??? This oil is most popularly used in diesel engines, has anyone ever heard of this.


Apprentice Goon
Mar 16, 2001
Charlestown, IN
Rotella T is probably a better oil for your bike than the majority of boutique "moto" oils, including the synthetics.
In fact, I would choose the 15w-40 conventional oil over their own 5w-40 GrpIII synthetic offering. I think it is more shear stable than the synthetic.
Oils marketed to diesel engines have lots of detergent/dispersants in the formula's, which is also a good thing for a wet clutched engine.

Unless you are starting the bike in sub-zero temps, there will probably be no added benefit by using a thinner winter rating, such as a 5w-x

RT 15w-40 is about $8 a gallon at WallyWorld.
Hard to beat.
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