Rotella T6 -> 5w40 vs 15w40?

[Yata-Garasu_imp]

I used Rotella T6 5W40 with no known side-effects or extra noise - in fact, the lump was quieter and gear shifting remarkably smoother compared to GN-4. Sub-zero winter riding also benefited being 5W and synthetic.

I would have never considered 15W40 for the CB1100, especially for cooler riding weather.

Same for me. I have used the T6 5W-40 for all my bikes for years. When new my 2013 CB1100 was reluctant to shift at times and excessively noisy, especially on hot days. First oil change I used the Honda synthetic 10W-30 and thought the problem would disappear as it broke in but problem continued. Next change was a switch to the T6 5W-40 and noise level was better and shifting stiffness disappeared. Best of all, T6 is a fraction of the cost of "motorcycle" oils. I do like the Honda oil filters as they are shown in tests to be better than most.

Same for me. I have used the T6 5W-40 for all my bikes for years. When new my 2013 CB1100 was reluctant to shift at times and excessively noisy, especially on hot days. First oil change I used the Honda synthetic 10W-30 and thought the problem would disappear as it broke in but problem continued. Next change was a switch to the T6 5W-40 and noise level was better and shifting stiffness disappeared. Best of all, T6 is a fraction of the cost of "motorcycle" oils. I do like the Honda oil filters as they are shown in tests to be better than most.
Has anyone here done a used oil analysis of the 5w40 after it's been in theIr CB1100 for a regular OCI? (4000 miles)

Over on the BITOG oil forum, several people complained that the 5w40 was shearing down very quickly in their shared sump bikes.

Since air cooled bikes are known to be hard on oil and I live in an area with hot summers, that's why I opted for the 15w40 instead of the 5w40.

I still think the Rotella 15w40 was at least as good as the Honda GN4 10w40. The GN4 literally looked like burnt coffee after 3500 miles. At least the 15w40 still looked like motor oil...

Again, so far I'm very happy with the T5 10w30. No shifting problems at all, and the dreaded "missing 2nd on occasion" hasnt happened once yet.

FWIW, I have been using the [url=https://www.amazon.com/Fram-PH6017A-Ph6017A-Outboard-Filter/dp/B000276B2C]Fram PH6017a.

Silicon drain back valve, improved flow compared to car filters, decent reviews, only $6 at Walmart, and it's BLACK like my bike!