Originally Posted By: Bonz
Originally Posted By: DoubleWasp
Wow. I think Mobil must have changed the formula on 15-50 again. 5500 miles in a Harley engine and it held viscosity that well? Incredible. Never seen M1 15-50 hold up that well since the old red cap formula.
The Harley is not a shared sump engine. IMO, I would expect viscosity to hold up well. Especially on the new engines with their cooling capability.
For comparison, I ran the same oil in my Kawasaki ZRX 1200 for 5000 miles, viscosity dropped down into the high 40 weight category.
True, Harley is not a shared sump engine but the Mobile 1 held up exceedingly well. Im actually quite surprised and very impressed. I have never been impressed with the Mobile 1 15w50 oil for use in motorcycles but I am now, it looks so good I wondered to myself if the OP got the oil grade right.
I assume he is correct in stating this is the Mobile 1 15w50 Automobile oil sold in the 5 quart containers.
Actually it would be incorrect to say "especially on new engines with their oil cooling capability" as the demands on the oil in the new 107 M8 engines far exceed anything in previous models simply because it is the oil now being used to actaully cool down the valves in the engine. The engine now has cooling passages around the valves in which oil is pumped through to remove heat from the valves. This is a first for the touring bikes.
The oil in the non water cooled M8 engines actually circulates around the valves to cool the valves down, this super heated oil then gets transported to the oil cooler.
Bottom line, I can say the oil temperatures must be unchanged or higher from previous Harley 103 touring bikes and must really climb if stuck in traffic, Harley lists oil pressure at a normal 230 degrees, which can be as much as 30 to 40 degrees higher in 100 degree weather on a 103 engine and I am sure the same or higher on the 107.
On the flip side, the much more expensive "Ultra" touring bikes have water cooling, one can safely assume oil temps will still be the same as the "Ultra" series bike does have water cooling but no oil cooler.
Again, like any bike, the oil is no hotter or cooler in any model year and this Mobile 1 did a good job for cheap automotive oil. Im impressed. (as long as the OP posted the right oil grade, ha ha)
You stated that on your shared sump bike the oil dropped into the 40 weight range, Im not sure if that is a typo as on any shared sump bike oil will drop a grade, you just dont want to drop two grades. But yes, for sure, on a shared sump bike oil will shear more, but it will also shear to a lessor degree (most times but not all) in a non shared sump such as an air cooled Harley as the hot operating temperatures can also contribute to shearing.