Benduro
Husqvarna
B Class
Just to play devil's advocate here...
The engineers who designed this motor recommend 50 weight.
What do we know happens when an oil is nearing its time to be changed in a bike like ours that shares oil with the gearbox?
Viscosity loss from "shearing".
I imagine when the interval is up, the oil that started as 50 weight is now around 40. Which, the engineers say...isn't heavy enough.
This whole 0w40 M1 camp is because they think that a lighter oil gets into tighter tolerances better, which, I'm sorry to say, is laughable.
When it gets into these mythical "tight spots" in our motor (that somehow the engineers didn't account for...lol) the oil isn't heavy enough for the anticipated load or stress!
We'll see accelerated wear, but if it's a race motor and you're going to tear it down anyway, maybe you don't care.
Me, I'm going to stick to spec.
M1 0w40 "european car formula" is fantastic oil. Very high quality. I run it in my MB sprinter and my tdi wagon.
I have it laying around in big, cheap jugs. I'm not gonna put it in my bike though. In my mind, ignoring spec and giving pseudo-engineering reasons for that is like if you were a concrete contractor and you were hired to do a driveway and the homeowner insisted on using gravel, not sand, under the slab because he has a big old pile out back that he got for cheap, and he read on the internet that it doesn't matter.
You, being a professional who very much knows what he's doing and have been doing this for a long time, try to tell him that there's a reason you use sand under a slab, it will keep it from cracking, and sand wasn't just arrived at all willy-nilly by people taking a random guess.
But ultimately, he's the homeowner!
The engineers can't do anything but unequivocally spec the oil the motor needs for it's anticipated loads. The consumer running another oil of a different weight might work out. Might not.
But I think the biggest factor in people running the M1 is the expense.
If a high quality, ester "true" synthetic, jaso ma2 yada yada 10w50 oil was the exact same cost in 5 liter jugs as the M1, do you really think anyone would run the M1?
The engineers who designed this motor recommend 50 weight.
What do we know happens when an oil is nearing its time to be changed in a bike like ours that shares oil with the gearbox?
Viscosity loss from "shearing".
I imagine when the interval is up, the oil that started as 50 weight is now around 40. Which, the engineers say...isn't heavy enough.
This whole 0w40 M1 camp is because they think that a lighter oil gets into tighter tolerances better, which, I'm sorry to say, is laughable.
When it gets into these mythical "tight spots" in our motor (that somehow the engineers didn't account for...lol) the oil isn't heavy enough for the anticipated load or stress!
We'll see accelerated wear, but if it's a race motor and you're going to tear it down anyway, maybe you don't care.
Me, I'm going to stick to spec.
M1 0w40 "european car formula" is fantastic oil. Very high quality. I run it in my MB sprinter and my tdi wagon.
I have it laying around in big, cheap jugs. I'm not gonna put it in my bike though. In my mind, ignoring spec and giving pseudo-engineering reasons for that is like if you were a concrete contractor and you were hired to do a driveway and the homeowner insisted on using gravel, not sand, under the slab because he has a big old pile out back that he got for cheap, and he read on the internet that it doesn't matter.
You, being a professional who very much knows what he's doing and have been doing this for a long time, try to tell him that there's a reason you use sand under a slab, it will keep it from cracking, and sand wasn't just arrived at all willy-nilly by people taking a random guess.
But ultimately, he's the homeowner!
The engineers can't do anything but unequivocally spec the oil the motor needs for it's anticipated loads. The consumer running another oil of a different weight might work out. Might not.
But I think the biggest factor in people running the M1 is the expense.
If a high quality, ester "true" synthetic, jaso ma2 yada yada 10w50 oil was the exact same cost in 5 liter jugs as the M1, do you really think anyone would run the M1?