Service manual favors 10W-30 oil

[Red Mist_imp]

This is page 3-14 of the Honda Service Manual for the 2013 Honda CB1100. This picture was taken from my copy, but it was pointed out to me by the Service Manager, (in his copy), at my local dealer. Read the sidebar, it clearly states that you may use "other viscosities" as listed on the chart, (40wt.), if the average temperature in your riding area is within the specified range. There are three places in the service manual that I have seen, that list specification for engine oil, this was the only place that mentions 40wt. oil. It is there, however, and that's enough.

The chart could be better, I interpret it as 60 degrees F or higher. The Service Manager added that they used 40wt. at set up for all of the CB1100s they sold, (salesman once told me they sold 12 of them). They have had no reported issues with it. I thought I was switching to 40wt when I did my first oil change, turns out, it had 40wt. from the start.

It's in the service manual, if you live in a warm climate, and you are using 40wt., you are ok.


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Believe what you wish, but it's right there in the service manual.

Absolutely, positively, my last comment ever on the subject of engine oil.

That chart seems to indicate that either weight can be used for the specified temperature range. The chart is not particularly clear on that, but charts which show temperature ranges per oil grade have a separate band for each grade. This one seems to show that either 10-30 or 10-40 is acceptable across the range shown.

My owner's manual is different. It only shows 10W30, nowhere in the manual does it recommend 10W40. Pages 46 & 122.

The manual for my Yamaha is quite different. It recommends a variety of oils for various temperature conditions; 10W30 is from -10 F to 70 F, while 10W40 is from -10 F to 110 F. It also allows 15W40, 15W50, and 20W50 depending on the temperature range to be expected.

Since the expected temperatures in my area will be in the 10W40 range, that's what I use.