Service manual favors 10W-30 oil

[furious_blue_imp]

I really, really didn't want to get in on this, however when I was down picking up oil and filters the other day for my bikes I asked the Parts Manager (27 years as parts manager) about this and he said and I quote " Up until 2006 Honda recommended 10w40 weight oil for their bikes. Starting in 2007 Honda started recommending you use 10 W 30 in their bikes" then he pointed to the following Honda chart which I took a picture of and am posting below

[url=http://smg.photobucket.com/user/theferret111/media/march31007_zpsa24bed3a.jpg.html]

So I said... so my ST is a 2006 and Honda wants me to use 10w40 but if it had been a 2007 ST it would call for 10W30? He said "Crazy huh?" I said yep!

So I bought a gal 10w40 for my 2006 ST (which is what I always used anyways) and a gal 10W30 for my 2014 CB 1100 as Honda recommends( which I used in my 13 anyways) plus 6 oil filters, an air cleaner for the ST, brakes all around for the ST etc

Americans are a stubborn bunch, as in "I've been using 20w50 synthetic dino oil in all my vehickles for 30 years and never had a problem" so keep on using any weight any type oil you have faith in, but Honda DOES "recommend" 10w30 for the CB 1100.(and all Honda motorcycles manufactured starting Jan 1, 2007)

Well. The obvious reason one weight is ok for one year and not the other is an engineering change, that being larger galleries or a higher oil pressure or both.

So, I suspect if the designer of my bike says 10w30 then by God they mean 10w30 and no generic shop manual overrides those specifications for a specific engine. At least one of you tends to waive some shop manual around like it somehow is the secret Gospel that only those in the know use to change owner specifications for a specific bike and my concern is some owner is going to belief you and damage their engine in the long run. I won't because I can clearly see Honda wants 10w30 with some additional motorcycle only specifications in the bike. This makes is simple for me to determine what weight and what grade oil must go into the CB1100 no matter if it rains or snows or is damn hot that day, 10w30 is it because Honda says it is. So it is. Nothing else. Wear your bike out with too heavy an oil on startup, where most wear occurs, but don't talk someone else into doing it.

Well. The obvious reason one weight is ok for one year and not the other is an engineering change, that being larger galleries or a higher oil pressure or both.

So, I suspect if the designer of my bike says 10w30 then by God they mean 10w30 and no generic shop manual overrides those specifications for a specific engine. At least one of you tends to waive some shop manual around like it somehow is the secret Gospel that only those in the know use to change owner specifications for a specific bike and my concern is some owner is going to belief you and damage their engine in the long run. I won't because I can clearly see Honda wants 10w30 with some additional motorcycle only specifications in the bike. This makes is simple for me to determine what weight and what grade oil must go into the CB1100 no matter if it rains or snows or is damn hot that day, 10w30 is it because Honda says it is. So it is. Nothing else. Wear your bike out with too heavy an oil on startup, where most wear occurs, but don't talk someone else into doing it.
I'm late to the oil party, but I completely agree with this. A motor from 10 years ago is probably NOT the same as a motor today, even if it does externally look like the one we knew 10 years ago..

'it's got 4 cylinders and is air-cooled, of COURSE I know what it is. I used X 10 years ago and it was fine, so I'll use X today, because that's what I did then and nothing bad happened !'

The situation kind of reminds me of when radial tires first started appearing.
The mechanics at the dealer were constantly under inflating my tires because they were probably just doing what they always did.

Multiple times I had to mention to the dealer that their mechanics did NOT read the specs and were underinflating the tires..