best grade of engine oil for the 660
 

Hello. Which grade of oil should i be using in the xtx??

Thanks

10/40
Motul 5100 or Yamalube "same thing"

Thank you

I used to buy Motul 5100 10w40 but last change i used BEL RAY THUMPER 15W50 as its was said on the site....
Does anyone have any opinion on that oil???

Oils
 

You need to ensure that whatever MAKE of oil u use (Castrol or whatever) you use the correct spec and grade of oil, as specified by the makers of the engine. In the XT660 the makers suggest a synthetic oil and a 10/40 grade, and it should be approved by JAPO (Japanese group of manufacturers). This ensures that the oil is approved my the group of Japanese motorcycle makers so for instance the viscosity etc is ok and the oil does not interfere with the clutch. OK???? Ciao xxx ps I use either Castrol or similar.