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Wrong Oil

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Yes, that is exactly what I am trying to do. Trying to figure out a way to stop doing that.
 
I have researched and can't find out exactly what is happening when we lug the engine. It's not in my old IC Engines textbook, nor in others I can find online. What you can find is people saying "it's the engine working too hard," which is a very unsatisfying answer for an engineer. It is not pre-ignition, because you can hear pre-ignition (knock), but you can't feel it. I have 3 hypotheses:

1. I suspect it is the collapse of the oil film in the conrod & main bearings, leading to the shaking. The way journal bearings work is (we'll use a stationary journal) the rotating portion "climbs the wall" and the closest point to the journal isn't straight down, but is towards one side of the journal, towards the direction of the motion. If we look at a main bearing end-on, if the crankshaft rotates clockwise then the closest point to contact will move from 6 o'clock towards 3 o'clock. The film thickness is proportional to engine speed and inversely proportional to load (high speed and low load = thicker film). Maybe that film gets too thin and we feel the crankshaft moving around in the bearing.

2. Another hypothesis is that with the thinner film thickness (journal bearings are running on a thin film of oil) the conrod bearings get slop in them. The motion is always confused on these since the load reverses. So maybe that's what causes the shaking.

3. My last is the simplest in that when the engine slows down we feel the piston throw more. The load is higher so the piston is pushing harder and we fel the back-and-forth motion more. This one seems the least likely to me.

I bet that real engine design engineers know the why of this but if they've published stuff on it, it isn't easy to find amongst the noise of unsatisfying information on the internet.
 
I have researched and can't find out exactly what is happening when we lug the engine. It's not in my old IC Engines textbook, nor in others I can find online. What you can find is people saying "it's the engine working too hard," which is a very unsatisfying answer for an engineer. It is not pre-ignition, because you can hear pre-ignition (knock), but you can't feel it. I have 3 hypotheses:

1. I suspect it is the collapse of the oil film in the conrod & main bearings, leading to the shaking. The way journal bearings work is (we'll use a stationary journal) the rotating portion "climbs the wall" and the closest point to the journal isn't straight down, but is towards one side of the journal, towards the direction of the motion. If we look at a main bearing end-on, if the crankshaft rotates clockwise then the closest point to contact will move from 6 o'clock towards 3 o'clock. The film thickness is proportional to engine speed and inversely proportional to load (high speed and low load = thicker film). Maybe that film gets too thin and we feel the crankshaft moving around in the bearing.

2. Another hypothesis is that with the thinner film thickness (journal bearings are running on a thin film of oil) the conrod bearings get slop in them. The motion is always confused on these since the load reverses. So maybe that's what causes the shaking.

3. My last is the simplest in that when the engine slows down we feel the piston throw more. The load is higher so the piston is pushing harder and we fel the back-and-forth motion more. This one seems the least likely to me.

I bet that real engine design engineers know the why of this but if they've published stuff on it, it isn't easy to find amongst the noise of unsatisfying information on the internet.
Thank you for taking the time to give that explanation and the research. I am very impressed. I am not mechanically inclined so thank you for explaining it in a way that is easy to understand. What, if anything, should be done? As I said earlier, I did experiment with manual down shifting, yesterday, and eventually settled on S2 mode, which made it better.

My worry is, will this chatter cause problems in the long run? People put 200k on this engine without issues. Am I going to be one of the unlucky ones? I know...you do not have fortune telling abilities. I am waiting for the delivery of the 10w30 oil next week.
 
Worry less, ride more.

Have you ever seen a Harley V-twin shake at idle?

Honda has even suggested in their marketing talks that the uneven feel of the NC engine was put there on purpose to give the engine "character".
 
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I know I am a little late to the party here, but people get too wrapped around the axle over oil viscosities, especially when it comes to the whole 10w-30 vs 10w-40 debate. I found a chart for recommended SAE oils given the outside temps. The range for 10w-30 is from -25C to +30C. 10w-40 is -25C to +40C. In other words, either one will work just fine. If you tend to live in a warmer climate, 10w-40 would be better. But again, the difference is so minuscule you won't notice a difference as far as engine life is concerned.

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Here is a link to the article that I found the graphic in if you want to read up on it also.
 
Worry less, ride more.

Agree 1,000,000%

I am on an NC/CTX facebook page, always same thing. "My motorcycle makes this noise" I've never seen another group of folks worry more about the noises their motorcycle makes than those who ride these bikes. The irony is I would put them up as some of the most reliable bikes ever made.

What is described here in this thread is no doubt the engine lugging in low rpms from being in a higher gear than what is needed for that particular environment.

If engine lugs, gear down and go on. Stay out of D mode if on a DCT and the lugging bothers you. D mode sucks. Sport Mode and override with the + button if you want to shift a little sooner than standard Sport mode shifts. Or...if you are on a newer DCT bike with the 3 different Sport modes, I've found Sport mode 1 is about perfect for where I want it to shift under normal driving. D mode is completely useless to me.

My dad worked as a Honda mechanic when he was young, he told me a story about asking his boss about a noise a bike he was working on was making. His boss listened to it, said it was normal, then said "Son, engines make noises. It's the performance we are after." Will never forget that saying.

If you pay attention to every tiny noise, overanalyze, worry, stress, be paranoid about every little thing, you can't enjoy the bike the way it's meant to be enjoyed. Trust me, if something really bad is going on with your bike, it won't be questionable as to whether it is normal or not, it will be apparent.

Worry less, ride more. Right to the point. I like it.
 
Agree 1,000,000%

I am on an NC/CTX facebook page, always same thing. "My motorcycle makes this noise" I've never seen another group of folks worry more about the noises their motorcycle makes than those who ride these bikes. The irony is I would put them up as some of the most reliable bikes ever made.

What is described here in this thread is no doubt the engine lugging in low rpms from being in a higher gear than what is needed for that particular environment.

If engine lugs, gear down and go on. Stay out of D mode if on a DCT and the lugging bothers you. D mode sucks. Sport Mode and override with the + button if you want to shift a little sooner than standard Sport mode shifts. Or...if you are on a newer DCT bike with the 3 different Sport modes, I've found Sport mode 1 is about perfect for where I want it to shift under normal driving. D mode is completely useless to me.

My dad worked as a Honda mechanic when he was young, he told me a story about asking his boss about a noise a bike he was working on was making. His boss listened to it, said it was normal, then said "Son, engines make noises. It's the performance we are after." Will never forget that saying.

If you pay attention to every tiny noise, overanalyze, worry, stress, be paranoid about every little thing, you can't enjoy the bike the way it's meant to be enjoyed. Trust me, if something really bad is going on with your bike, it won't be questionable as to whether it is normal or not, it will be apparent.

Worry less, ride more. Right to the point. I like it.
Yep, reason I wear bluetooth ear buds and listen to music....If I didnt wear ear buds, I couldnt stand the noise any of my bikes make (2007 c50 boulevard with 101,000+ miles, my 2013 nc700x with 57,000 miles, and my 2009 Kawasaki klx 250sf with less than 6,000 miles-kept in storage in florida when I go on vacation down there)....all 3 engines make a different noise and all are stock exhaust so the exhaust isnt louder than the engines.
 
I'm over in the UK...
10w30 is the norm, DCT is meant to be a little fussy - but a lot will depend on temperature... to give the viscosity - We are Hot at the mo, but what is HOT for us aint what is HOT for you?
D can feel a bit 'lumpy' but thats more to do with the firing... I tend to use S... feels smoother at lower revs, and stops the bike changing its mind so much, especially around town, and less laboured...
All said and done... Honda designed it so all is fine...
 
Ok, I've put nearly 10,000 miles on my NC750X manual transmission in 9 months and it does have a peculiar engine! I very much think what you are describing as "chatter" is low rpm lugging of the engine. Has anyone noticed the suggested shift points for the manual transmission? I don't have the manual in front of me, but it's ridiculously low, something like 29mph then into 6th! I can chug along in 6th very slowly, but must downshift to accelerate. I think the DCT in D mode is set to shift at very low rpm and hold onto that gear as long as possible. It's my understanding that the firing order stager actually gives better grip in soft conditions by allowing that (ever so slight) pause in power to the wheel. Do you notice the engine almost rhythmically pulsing you along when at moderate rpm? You'll never experience this on your DCT, but I've noticed my engine can be killed very easily if the rps are a little low and you release a little too much clutch between that power stroke and that pause! BTW, I've run 10-40W full synthetic motorcycle oil since the first change at 600 miles.
 
I had a look at a 2020 service manual.
Pictures below are for the naysayers LOL

As you can see, there is absolutely no mention of GN4 10W-40 being acceptable, or any 10W-40 for that matter.
So, I will definitely use only Honda GN4 10W-30, because most other manufacturers of oil have only synthetic 10W-30.
And that's not what Honda recommends.DSC00056.JPG


DSC00057.JPG


I hope this puts to rest the notion that Honda says 10W-40 is recommended.
 
I had a look at a 2020 service manual.
Pictures below are for the naysayers LOL

As you can see, there is absolutely no mention of GN4 10W-40 being acceptable, or any 10W-40 for that matter.
So, I will definitely use only Honda GN4 10W-30, because most other manufacturers of oil have only synthetic 10W-30.
And that's not what Honda recommends.View attachment 43762


View attachment 43763


I hope this puts to rest the notion that Honda says 10W-40 is recommended.
bigbird, please take a look at and post a photo of the page in the maintence section of your 2016-2020 service manual, where the manual actually tells you the oil level inspection and engine oil change procedures. If it is like my 2012 service manual, it will have an ambient temperature/oil viscosity chart, like mine shows below. I’m very curious if Honda changed their recommendation for acceptable oil viscosity for later models, and the viscosity chart has been changed.

4E7A03B4-5061-4769-9104-0257BDABFCAA.jpeg
 
My service manual has the same pic which 670cc posted; if 10w40 wasnt acceptable, they wouldn't have it in the chart....It is a recommendation.....not a must use, not a 'have to use'.....not going to mention the oil I use (on my 2013 NC700 with 54,000+ miles, my 2007 C50 Boulevard with 101,000+ miles, and my 2009 Klx 250sf with 6000 miles)....you guys would cringe....
 
I’m just wondering if Honda is transitioning from 10W-40 to 10W-30 across the product line as the years have gone by. In my current fleet of Hondas, I have a 2002 and a 2003 that specify 10W-40 only. I have a 2007 and a 2009, as well as my 2012 NC700X that call for 10W-30 or 10W-40, while my 2017 CRF calls for 10W-30 only.

I am anxious to see a picture of the ambient temperature/oil viscosity chart from the 2016-2020 Honda NC service manual. Can anyone post it, please?
 
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Here's the pages you wanted.
There is no temp/viscosity chart in the '16-'20 service manual, only Honda's recommendation for oil weight and type.
So obviously Honda has changed their recommended oil viscosity, al the way back to model year 2016.

You guys can and will do whatever you want in terms of oil weight and type.
I'll go with Honda's recommendation.
I am not smarter than any of their engineers.

This same predicament happened on the biggest Goldwing forum back in 2018 when the new model with DCT was released.
I had a 2013, and its service manual also had the exact same viscosity/temp chart as the older NC service manual.
The debate raged, and still does.

I have a feeling that Honda doesn't want anyone using synthetic oil in their engines for wet clutch reasons, unless the design of the engine warrants a synthetic.
I know that their high performance motocrossers and sport bikes recommend HP4S oil, rather than GN4.
In the Goldwing world, the guy who owns a specialty Goldwing shop and fixes hundreds of Goldwing transmissions every year does not recommend running synthetic oil.
He has seen clutch glazing only on Goldwing clutches that have run synthetic oil or have been abused by doing lots of crawling speed clutch feathering.
 
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View attachment 43765

View attachment 43766


Here's the pages you wanted.
There is no temp/viscosity chart in the '16-'20 service manual, only Honda's recommendation for oil weight and type.
So obviously Honda has changed their recommended oil viscosity, al the way back to model year 2016.

You guys can and will do whatever you want in terms of oil weight and type.
I'll go with Honda's recommendation.
I am not smarter than any of their engineers.

This same predicament happened on the biggest Goldwing forum back in 2018 when the new model with DCT was released.
I had a 2013, and its service manual also had the exact same viscosity/temp chart as the older NC service manual.
The debate raged, and still does.

I have a feeling that Honda doesn't want anyone using synthetic oil in their engines for wet clutch reasons, unless the design of the engine warrants a synthetic.
I know that their high performance motocrossers and sport bikes recommend HP4S oil, rather than GN4.
In the Goldwing world, the guy who owns a specialty Goldwing shop and fixes hundreds of Goldwing transmissions every year does not recommend running synthetic oil.
He has seen clutch glazing only on Goldwing clutches that have run synthetic oil or have been abused by doing lots of crawling speed clutch feathering.
Thanks, bigbird.

This has been an informative thread. Now, I’m just a guy sitting at a keyboard and chatting on the internet, but here is what I see and the conclusion I have reached:

Over the past 15 years or so, Honda has gradually shifted from recommending 10W-40 oil to 10W-30 oil, across the motorcycle product line. That change has apparently happened even through the progression of model years for a given motorcycle model, even though the engine mechanicals have not significantly changed. The ambient temperature/oil viscosity chart has also disappeared in the latest NC service manual, and is not present either in my 2017-2018 CRF250 service manual. So, I have to say that Honda has steered the NC oil recommendation solidly toward 10W-30. These observations have cleared up the confusion for me, and going forward I will be primarily using 10W-30 in all of my Honda scooters and motorcycles, except for the 2002 and 2003 models, which will get 10W-40.

That being said, my NC700X seems totally oblivious to whether it has 10W-30 or 10W-40 in it. The smoothness of operation and fuel economy are unaffected by the oil viscosity. I still think people in general put too much thought into motor oil. If I had excess 10W-40 in my stock and a shortage of 10W-30, I wouldn’t hesitate to put the 10W-40 in my 2012 NC. If Honda said it was OK to use in 2012, it’s OK to use in 2021.
 
I would agree, Greg.

However, I would stay away from synthetic and stick to straight mineral oil.
It is unnecessary IMHO, and may not be the best diet for the clutch (clutches in the DCT).
I would really like to hear what the engineers in Japan have to say about that.

One thing I forgot.
In the Goldwing discussions, it was mentioned that 10W-40 (mineral GN4) would likely run hotter than 10W-30 GN4.
The explanation was that the additives that made the molecule's chains longer at higher temp to boost the oil from a 30 to 40 weight would also cause increased internal friction.
I don't know if that is even a measurable variable, but it was mentioned.
On the other hand, all oils shear down with use in an engine that shares its oil with the transmission.
But I assume factory testing with OEM 10W-30 GN4 oil has made this a moot point, as shearing doesn't seem to be an issue according to the owner's and factory service manuals.
 
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