I have read online where quite a few people swear by this oil. It's actually a heavy duty truck oil that doesn't have the friction modifiers put in regular automotive oil. Those modifiers are what you don't want running in your transmission. From what I read online Rotella has only recently been approved and meets JASO-MA standards. After reading this, I looked at the auto store and the certification was on the bottle. 1gal $11.50 Maybe this is old news.
Comments? BTW only the 15W-40 is JASO-MA
Dan

 

Old news, but good tip for those that want to follow the manufactures suggestion but don't want to pay for overpriced bike shop brand oils.

The 5w40 in the api-CJ spec would probably meet the spec too. The older CI spec diesel oils that have worked fine in bikes for years wouldn't have met the jaso spec due to higher ash content. The new CJ oils have lowered the ash.

 

This is really interesting, except I'm concerned that 15w part would be very hard starting on a cold day.

 

No worries about cold starts. Since no one sells 20w-50 in South Dakota, I run Rotella in everything, Chevy K10, Ford Bronco, and of course my beloved KLX250s. This far north its about the thickest oil you can find. I used to live in Texas and ran it there too. From 110degF to-10degF I never had any problems with it.

 

Now you've done it, dan...an oil thread.

Seriously though, I've always run a 15W-50 Mobil 1 oil in my KLR650's even though 10W-40 is recommended. After owning a KLX250/300 now for awhile, however, I notice it runs noticeably cooler than the 4 KLR's I've owned. The in-hose temp sensor on my KLX seems very accurate. The highest I've seen on my 300 cylinder equipped KLX250S is about 204 degrees for a very short period during wide-open-throttle on a long trail of deep sand. In those same conditions, my KLR650 had the fan on almost all the time with even a little coolant puking out of the reservoir tank. 204 degrees for a short period under these extreme sand conditions on a warm day isn't very tough on this motor. Because of this, I'm staying with 10W-40, as I think this motor doesn't need the higher viscosity that I believe my KLR did.

That said, I doubt there will be engine damage or problems with the higher viscosity, but maybe it just won't be the ideal match. In winter I wouldn't go to 15W-40, even in Texas on the KLX.

 

I'm pretty sure viscosity is covered in the owners manual.

 

Yeah, but there are some pretty big overlaps in the temp range. Maybe the viscosity issue is just more of what's ideal as opposed to what will work. And in that light, it leaves a lot of variables. But alas...dan's original post wasn't really focused on viscosity, so I'll shut up. Sorry dan.

 

Or maybe you could take the hint. It's not that complicated.

 

Lighten up Francis.

Some good reference info there ozz and TNC, I may give the Rotella a try, at least in the summer. I just posted it up because I knew at one point it wasn't certified, and now it is.
Dan

 

I had a 2005 KLR650 for some years. I tried some Delo 400 14W-40 diesel motor oil in it. It worked all right in the warmer months, but in the colder winter months, it caused the engine to knock like hell on cold start ups. As soon as I went back to the10W-40 I had been using-no more cold start knocking. I ran that bike for like 15,000+ miles until I traded it for another bike. I was surprised that such a seemingly small change in viscosity would cause this, but cause it it did. Never had a problem with the thinner oil. Your results may be different than mine.

On the other hand, on a 2001 KLR250 I had a problem with it popping out of second gear after the 1st/2nd shift unless I did a slow and very deliberate shift. I tried some Mobile One 10W-40 synthetic and the shifting problem literally never happened again.

jon