Synthetic oil?

I have a 2001 YZ426 and was told not to run synthetic oil. However, in the thread titled Yamalube below I see that some people are running synthetic oil. I was told not to because it makes the clutch slip too much or not catch at all? Is this correct? Am I safe to run synthetic oil in the bike?

You CAN run synthetic...most of us do. You MUST make sure it does NOT say 'Energy Conserving" on the info label/seal. Oils marked "Energy Conserving" (most automotive oils) have friction modifiers in them that can cause clutch slipping/damage.

On the back of the bottle, there should be a circle at the bottom of the label showing the API service grade of the oil. The potentially problematic oils will be labeled API "EC II". These oils MAY cause clutch problems. An oil labeled JASO MA is certified as compatible with motorcycle wet clutches, whether it's synthetic or not.

I have always run Amsoil synthetic in my 250f and I will testify in front of a jury of my peers that it has definantly contributed to the mutant-like longevity of the engine in that machine. :thumbsup:

Mobil 1 mx4t 10/40 has never let me down change ever 6 to 8 hours

i run full and it works great!

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