The racing guys all recommend a lighter weight oil for KTM motors - Zip Ty Racing recommends Mobile 1 0-40 oil. You can get this stuff at Wally World for about $24 for 5 liters. I just kind of get crazy when someone tells me I need to use $20+ a liter oil.....I also don't buy off on a 6,000 mile oil change interval as well....Buy good oil, use a stainless steel mesh oil filter(s) and change the oil often.