Man, dirt bike specific oil is high! Can’t I use automotive oil and just change it every time? My answer is no but you do what you want.
For starters, lets talk about the oils journey in the engine. 4 strokes use a recirculation oil system. Oil is forced into the filter by an engine driven pump. The filter picks up large particles that should not be there. After it goes through the filter, the oil enters the oil pump and then fed throughout the engine.
Minimizing heat and friction build up is important. Low quality oils fail at doing this.
The next concern is premature wear. Automotive oil lacks cleanliness or detergent. This can increase deposit accumulation resulting in power loss.
Automotive oil can increase clutch slippage in bikes with wet clutches. Even bikes with split cases, using the cheap oil in the clutch side can cause faster wear to the clutch plates.
In a years’ time, more money will be spent using the “cheaper oil” due to more frequent oil changes, oil filter replacement, and premature engine wear. So, I recommend sucking it up and spending the extra money on dirt bike specific oils. In the end, it really is cheaper even if the price on the bottle does not look that way.
BETA RIDERS – Beta recommends Motul in their bikes, Transoil on the clutch side and 7100 10W-40 on engine side. Motul 7100 4T runs cooler than most oils and will work well in 2T clutches.
Sherco has a wet clutch (meaning the cases are not split and the clutch and engine oil are in one spot), so make sure you are using a wet clutch oil such as Bel-Ray Thumper.