Diesel truck oil in a motorcycle?

I bought a KTM 520MXC last weekend. The guy I bought it from is a KTM fanatic and he runs Rotella T 15W40 diesel truck oil in his four stroke bike. He has a 2003 KTM 525 with well over 1000 hours on it, and he uses the Rotella T in that as well. Is this something that a lot of people do? Does anybody have an opinion on this? I have always ran Spectro 10W40 in my four strokes.

15 Answers

  • 1 decade ago
    Favorite Answer

    A whole lot of people swear by the Rotella 15W40 oil. You can go to just about any motorcycle forum and do a search on oil and you'll see what I mean. Personally I use Valvoline motorcycle oil in my bike though.

    Here is an eye opening link about the different kinds of oils that are good for motorcycles. Read the whole thing if you have time, it's not that long. The author is a chemist from Houston.


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  • goodie
    Lv 4
    3 years ago

    Rotella Motorcycle Oil

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  • Susan
    Lv 4
    4 years ago

    Because of the soot in diesel motors the oil has a lot of detergent additives to keep this from clogging things up. In a used petrol car engine this will lift any deposits of the internals and hopefully drop them in the filter. A m/c engine generally only has a strainer so the rubbish will circulate until the oil change and that may not be good on a long term basis. On the other hand any oil is better than low oil, and the diesel variety may make a worn engine quieter as the thickness is greater. I ran a Norton ES2 with EP90 gear oil for a few miles once as I had no other available after a major leak had emptied it. No problems later.

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  • Anonymous
    5 years ago

    This Site Might Help You.


    Diesel truck oil in a motorcycle?

    I bought a KTM 520MXC last weekend. The guy I bought it from is a KTM fanatic and he runs Rotella T 15W40 diesel truck oil in his four stroke bike. He has a 2003 KTM 525 with well over 1000 hours on it, and he uses the Rotella T in that as well. Is this something that a lot of people do? Does...

    Source(s): diesel truck oil motorcycle: https://biturl.im/j04BB
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  • 1 decade ago

    15-40 Diesel truck oil is very good choice for many motorcycles- much better than the 10-30 new car oils with low zinc content that lacks cushioning and sliding friction capabilities. I have run the diesel oil in Harley's and BMW's- shops have noted it as acceptable for the air cooled engines under normal use. 20-50 Valvoline motorcycle oil for hottest days or racing preferred for some use- straight 50 in desert racing . The diesel sped CD oils are high detergent, high stress capable, high heat capable- best choice at most gas station on road now. straight 40 weight diesel oil was used a lot in old Panheads and sportsters in 1970s when I started riding- dealer recommended as available on road trips. .

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  • Anonymous
    1 decade ago

    It has nothing to do with the viscosity of the oil, it has to do with the pressure ratings etc. Newer 4 stroke engines run with higher compression, have stronger clutches and have severe torque on their gears. I first read about this on adventure rider and then investigated it further online. If you only trust what the dealer tells you (and your doctor too) then do what they say. My first experience was with a brand new '85 quadsport. First oil change after break in using Genuine Suzy oil, the clutch sounded horrible and I had to adjust the idle up. One short ride made me think the engine was falling apart. Drained the oil to look for metal, found none. Changed oil to Castro GTX.... noise went away and I had to adjust the idle back down. I have other experiences that have taught me to trust oils made by people who specialize in oil, not making bikes. I'm not claiming to be an expert, just sharing what I've learned. With a few searches, you can find the chemical experts who can explain why diesel formulated oils are better in these situations. BTW Rotella T 15-40 in my '00 DRZ for last 3 years (approx 4,000 mi) and in my '00 Pegaso for the last 12,000 mi. My kids still put Castol in the quadsport and the engine has never been apart.

    Source(s): ADVrider.com
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  • 1 decade ago

    Good going curmedgeon, someone finally hit the nail on the head. Newer gasoline oils as well as the latest diesel oils are low zinc, something that's important for reducing cam lobe wear. If your engine of any type has roller tappets, it doesn't matter but most bikes don't. As mentioned, go for the CD oils and not the latest CF or whatever they are. In short, look for oils made for older diesel engines whether farm tractors, trucks or whatever.

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  • 1 decade ago

    The reasons for using (some types of) diesel oil in a bike are the similar demands placed on oils by bike engines and diesels.

    The shear-strength,ie the oil-film, is less likely to fail in a high pressure environment such as m'bike gearboxes where the oil is shared with the engine (unlike cars,),

    Higher film strength so less drain down when stood idle for extended periods

    Lack of friction modifiers, so no danger of (wet) clutch -slip,

    Additive packages with phosphorus and zinc, again beneficial to gearboxes, not in car applications because of catalytic exhausts, not on so many bikes.

    The synthetic Rotella seems to be the best choice, but with diesel oil specifications changing to meet the upcoming requirements regarding particulate filters on diesel applications, this may change.

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  • 6 years ago

    I've owned various scooters (150cc chinese POS, 400c Burgman) and various bikes (750 shadow, 250 ninja, cbr250).

    I think what matters more is using the weight designated in the owner's manual, and changing it according to interval.

    Here's why I say this...

    The burgman ran 15w40. I put Rotella 1540 into it. The scooter & bikes recommended 10w40, or a slight variation of weight based on temp or riding conditions. None of them got very anal about diesel vs. car vs. motorcycle. Most said any vehicle (read as "automobile / motorcycle") oil would work.

    Why? Because these vehicles are designed to be low maintenance. Nobody wants to pop tons of money on an oil change on a motorcycle. So, engineer/manufacturer designed them to just use off-the-shelf motor oils you can find at any auto store around the corner. It's cheap, convenient, etc.

    Folks split hairs over type of oil (synth vs. dino/mineral), auto vs. motorcycle vs. diesel, and other BS. If they love to do that, that's great. That's their thing. But, bottomline, if you're just using your motorcycle and want to run it, just get a motor oil within the designated weight of your owner's manual. The manufacturer will almost always recommend their specific brand (eg: Honda always recommends their specific, more-expensive Honda brand of oil), but they state in the manual any oil falling in the weight range they give is acceptable.

    If you're looking to magically eek out performance based on the type of oil you use, then you're splitting such a fine hair on a head full of hair it's not even funny.

    As for oil changes, newer bikes (post-2000) can get away with greater intervals between changes. Cars and bikes in the past needed a change every 3-4k. But, if you look at car owner manuals most cars can go a good 10k+ between changes. Bikes are the same. Used to need a change every 2-3k, but now you can go 6k+. My shadow 750 could go 8k between changes. Same with the cbr250.

    If you want to change the oil sooner, so be it. But, the biggest thing is to at least run the oil 1k+ or so. This lets the oil break in and run effectively. You could change your oil every 500 miles if you want, but you'd be wasting your money and not running the oil in it's optimial time frame (1k+ miles).

    The biggest thign you can do for your motorcycle is just

    1) use the oil within the weight the manual recommends

    2) change it per your manual's interval (or maybe before then... some folks change it at 1/2 the interval their manual recommends).

    The biggest consideration in oil changing is how much stress is on the bike. When I ran my little 150cc scooter I changed it every 2000 miles even though it said 4000 miles. Why? Because I'm a fat guy, and it hauling me around was putting a lot of strain on the motor. For the 750 Shadow, which is designed for hauling a fat-*** and/or two-upping, it could haul me around without breaking a sweat. I changed it every 8000 miles.

    Bottomline, changing the oil is better than not changing the oil, and using motor oil is better than tossing cooking oil into it. Just ride it, have fun, and don't sweat the small stuff. If you really want more performance, then sweat over upgrading to a bigger bike, not over the type of oil you put in your current one.

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  • 1 decade ago

    I don't understand why people think they can outsmart the engineers that developed the formulation for motorcycle engines. How can an oil designed for a huge, lazy, sooty engine that red-lines under 4,000 RPM be a good choice for a small, high revving, high tolerance motorcycle engine, some of which spin up to 15,000 RPM?

    I just don't get it.

    I buy conventional motorcycle oil in the grade that my manual tells me to buy, and I have never had a problem.

    Edit: Great link "Mr. Natural" Thanks!

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