Rotella 15w40 T4 & T6 in Motorcycles

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I'm starting this thread to compare the two flavors of Rotella 15w40 in motorcycles.

Apparently the synthetic T6 was only available in 5w40 for many years, so if you wanted a Rotella 15w40, you were looking at the T4 "Dino" oil.

I've been very happy using T4 15w40 in my Nighthawk 750 (air cooled inline 4) and my Shadow 750 (liquid cooled V-Twin).

Last Spring I acquired a new-to-me CB1100, very similar to the Nighthawk 750, an air cooled inline 4.

I was thinking about using the T4 in it, but the Honda dealership threw in an oil change with the bike, so I just went with the Honda oil.

Oddly enough, the manual calls for 10w30, but the dealership only had 10w40. She got the 10w40 and it's been fine.

Now I want to change the oil before the winter season. Here in Dallas winter is still ridable, but not nearly as often or as far. I rarely ride below 40F, and I never ride below freezing... At least not on purpose

My experience with the Nighthawk and Shadow is that the T4 15w40 is better oil than Honda's oil. Ie, shifting is smoother and it maintains a transparent amber color for longer.

I don't know if looking cleaner is actually a good thing, but it's psychologically reassuring to check my motor oil with 2k miles on it and it still looks new!

Over on the CB1100 Forum, if you ask any kind of oil question, it generates a bunch of snarky comments.

Apparently quite a few people there are using the T6 5w40, but of course there are also the Honda loyalists who insist on using Honda oil in any kind of Honda product.

Looking at the TBN and shear resistance of the T6 5w40, and it doesn't seem like the 5w40 is the best choice.

Anyhow, I got a couple of gallons of the T6 15w40, and I plan to try it in both the Shadow 750 (currently running T4) and the CB1100 (currently running Honda 10w40 dino oil)

I average between 3 and 4 thousand miles a year per bike, so I usually just change the oil annually.

I'll let you know what I find out!
 

Jay Freddy

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T5 is also a great choice.
I never considered the T5 because it doesn't meet JASO MA/MA2 specs.

The previous owner of my Shadow used Castrol 10w40 car oil, and the shifting was starting to get notchy when I bought it...

After 200 miles with the T4 15w40 and she was shifting smooth as silk.
 
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I might think about the T6 5w40 in the cold weather because motorcycle batteries are not known for their overwhelming capacity and I notice slow cranks running 15w40 in the late fall. Shearing should not be a problem if Honda is calling for a 30, the 40 will just shear down to a 30 after 1k or so. All this said I would not run a 5w40 or a 10w30 in an air cooled bike in Dallas in the summer. As long as your moving along they might be ok but if you get stuck in traffic I would want that 15w40.
 
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Just a thought but could you just change the oil for winter and then back to a heavier oil for summer but leave the filter for once a year. The filter is the messy part anyway, the oil is quick and cheap.
 
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I can’t help you with motorcycles however I have extensive experience running the T3/4 15w40 and T6 5w40 in a Kawasaki Bayou 250. The 15w40 worked great but was stiff to shift in colder temperatures. The T6 is my go-to now in 5w40, it starts great even below 0 and shifts like butter.
 

Jay Freddy

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I can’t help you with motorcycles however I have extensive experience running the T3/4 15w40 and T6 5w40 in a Kawasaki Bayou 250. The 15w40 worked great but was stiff to shift in colder temperatures. The T6 is my go-to now in 5w40, it starts great even below 0 and shifts like butter.
Many people on the CB1100 forum seem to be very happy with the 5w40 too, but from the test results I have seen, it shears pretty quickly. Also, the result of using overly thin oil is premature cam shaft wear, which you don't notice until it's too late.

It's 60F today in Dallas, a fine Winter Solstice... Hoping I can get in a ride before the sun goes down and it goes down to 30F again tonight!
 
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I never considered the T5 because it doesn't meet JASO MA/MA2 specs.

The previous owner of my Shadow used Castrol 10w40 car oil, and the shifting was starting to get notchy when I bought it...

After 200 miles with the T4 15w40 and she was shifting smooth as silk.
T5 10w30 works very good as transmission oil in my vintage 2 stroke road motorcycles. Works better than t6 5w40.
 
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T5 is also a great choice.
I did an OCI in my shared sump ZRX1200 when T5 15w40 first came out. The oil worked fine and stayed in grade for 3200 miles. The subtleties of these oils aren't rocket science. T4 had no JASO lettering on the bottle for millions and millions of miles in motorcycles with riders using experience to evaluate effectiveness. I have used T5 15w40 oil, it's worked fine. Others who have used it and it didn't work, speak up.

Yes, it's been shared many times on this forum that T5 5W40 is a shear monster. Don't use it if you value lasting shift quality.

As well, a good 10w40 will not shear down to a 30 grade in 1,000 miles. M1 10W40 4T stays in grade for 5,000+ mile OCI's in above said ZRX1200.

As another thought, dirty oil shows it's doing it's job, what is clean oil leaving behind?
 
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Jay Freddy

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As another thought, dirty oil shows it's doing it's job, what is clean oil leaving behind?

I have never heard anyone claim that an oil that turns black faster is doing a better job! If that were a valid metric to gauge oil quality, a bunch of manufacturers would be selling black oil right out of the bottle... And wouldn't that have at least some correlation with the filter?!

Also, if T5 were good in wet clutch applications, why would Shell go through the trouble of getting T4 and T6 spec'd for JASO MA, but not T5?

Interesting thoughts! Thank you for your reply!
 

Jay Freddy

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PS. I started using Rotella T in my bikes when it was only available as "Dino Oil" and wasn't JASO/MA spec'd. But now that some varieties are spec'd for JASO/MA, I'm not sure why Shell would limit the oils that get the spec unless there were qualitative differences in how they perform in wet clutch applications.
 
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The newest T5 is not even gasoline rated on the bottle. I called Shell and they told me there was no difference in formulation they just didn't put it on the jug. T5 was one of the best I've run as far as shift quality goes. My bike is air cooled and destroys oil quickly where I ride, SW desert. As far as T6 5W40 goes; it lasted about 900Mi before the shift quality went downhill, not impressed.
MHO
Smoky
 
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Lol, my comment about dirty oil that is (within a reasonable OCI) is more to make light of the fact that dirty or clean appearing oil is just that, appearance. About as immaterial to performance as a JASO rating on an HDEO oil of about any type. They work. Smoky 14 has a great experience with T5 15w40, as do I. Read that as experience, not conjecture about what is on the bottle. If read him correctly, Shell says it's fine as well with no difference in formulation. Rotella T5 15w40 "debate" is much ado about nothing.

As well, Shell does nothing to certify. They know oil and what makes it work in any type vehicle they want to put on the bottle. What Smoky14 shared sounds like they have more things on their mind than changing the T5 jug, but I bet they enjoy reading forums with "conspiracy" theories. In the spirit of the holiday season, Shell is probably reading right now and "Laughing all the way, ho, ho, ho".
 
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The newest T5 is not even gasoline rated on the bottle. I called Shell and they told me there was no difference in formulation they just didn't put it on the jug. T5 was one of the best I've run as far as shift quality goes. My bike is air cooled and destroys oil quickly where I ride, SW desert. As far as T6 5W40 goes; it lasted about 900Mi before the shift quality went downhill, not impressed.
MHO
Smoky
Try T4 - Your Suzuki will love it.
 

Jay Freddy

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The newest T5 is not even gasoline rated on the bottle. I called Shell and they told me there was no difference in formulation they just didn't put it on the jug. T5 was one of the best I've run as far as shift quality goes. My bike is air cooled and destroys oil quickly where I ride, SW desert. As far as T6 5W40 goes; it lasted about 900Mi before the shift quality went downhill, not impressed.
MHO
Smoky
No difference in formulation compared to the old T5? Or compared to T4?
 

Jay Freddy

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Lol, my comment about dirty oil that is (within a reasonable OCI) is more to make light of the fact that dirty or clean appearing oil is just that, appearance. About as immaterial to performance as a JASO rating on an HDEO oil of about any type. They work. Smoky 14 has a great experience with T5 15w40, as do I. Read that as experience, not conjecture about what is on the bottle. If read him correctly, Shell says it's fine as well with no difference in formulation. Rotella T5 15w40 "debate" is much ado about nothing.

As well, Shell does nothing to certify. They know oil and what makes it work in any type vehicle they want to put on the bottle. What Smoky14 shared sounds like they have more things on their mind than changing the T5 jug, but I bet they enjoy reading forums with "conspiracy" theories. In the spirit of the holiday season, Shell is probably reading right now and "Laughing all the way, ho, ho, ho".
I agree that Shell knows oil... My personal experience is that T4 15w40 is a superior performing motor oil in my Honda motorcycles even compared to Honda brand dino oil. I haven't tried Honda's synthetic oil yet, probably never will.

My main curiosity with this thread is whether the T6 15w40 will outperform the same grade T4 15w40 in terms of resistance to sheer, high temps, extended OCIs, and cold starts.

I haven't had a problem with the T4 15w40 for cold starts as low as 32F, but I imagine the fully synthetic might just be a little smoother for cold starts, and give me a little more cushion on the OCI too.

I will likely still change the oil once a year, I'm lazy, but I like having a little extra cushion if I can get it.
 
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