From what I understand. You can use any oil that's JASO approved (motorcycle oil). Diesel oil like chevron, rotella, DEC, mobil, and a couple others was JASO approved. It just that the companys just didn't want to pay for the approval to get it tested and left it as is. Diesel oil. Motorcycle oil is diesel oil but been tested to get approved as JASO. Now this is what I read and just relating it back to you guys on this forum so fellas don't bash on me to much..
Sadly I read way too many oil forums(newer thought nearly this much about any car I owned...) and at the end there still isn't a clear answer in my mind. FWIW, here is what I gleaned from the articles:
- Run the recommended Yamalube within scheduled changes and you should be fine. Will Yamaha cover repairs down the road because you used Yamalube? Who knows. Unless you have the extended warranty I have my doubts.
- MC oil has different viscosity modifiers (what allows it to go from 10 to 40, 20 to 50 etc.) than car oil. These modifiers can handle the mechanical thrashing they get going through the transmission gears. Car oils won't and the top end, 40 or 50 weight, could be halved in a short period which would be bad. You end up possibly getting a 20-25 weight in the heat of summer ???
- Diesel oils(like Shell Rotella) that are JASO certified should be fine as long as everything else matches up.
- Dino verses synthetic seems to be a personal choice assuming you are following the normal change windows. Truckers tend to run their diesel oil a lot longer but they do get it tested to make sure everything is still fine. Not many car/MC owners are going this step. The truckers do it because those huge honking diesels they have take a lot of oil!!
- Synthetic does seem to run a touch cooler so if you are in a high heat area it might be worth the investment.
Bottom line to me is this: Make a choice and go with it. If things seem the same or better(like gear changes) stay with it. If not, change the oil ASAP with another brand/type, recommended or previously used, and consider this a life lessen.
I believe not all MC engines can be classified the same, just like cars cannot, and, therefore, what works for another MC might not be the same great fit for our Stryker's.
Note: I take all manufacturers claims/advertisements worth a grain of salt unless backed up by an outside scientific test.
Also Note: I, personally, don't think you can do any harm to your motor short term trying a different oil than Yamalube. All oils today are so stinking advanced you'd be hard pressed to find a bad one that would do damage unless you are in the "extreme" category and if you are you already know you need to run the expensive stuff and change it more often!!
And, finally, just like in the car, if something starts making noises after you do changes/mods pull over as soon as it is safe. We probably all have had a Homer Simpson moment after some of our mods. In fact that would be a great thread to start...