Vibration/pulsing at 50 - 55 MPH in 6th

[Beemerphile]

I agree with Little Ed. The point is, and it was missed by a few of you, that some of us NC owners are experiencing the odd pulsation and some are not (I am.) If it was normal, all would be experiencing it. There appears to be a common problem and it needs further investigation. I am monitoring this thread with great interest and hope a solution can be found.

This may be so. The issue is so subtle on mine that I hardly notice it and it certainly does not bother me. That leaves open the options that:

1) My bike doesn't have the "problem"
2) I have lower expectations of "smoothness"

So we are dealing either with a problem that only some bikes have (as you say), or an issue that is common to all the bikes but only some of us view as abnormal. It is not clear to me whether I have the "problem" or not. But after riding old clackity airhead BMW's for so long that shudder and shake like an old horse, it may be that my expectations are too low.

 

[happy]

As I mentioned before, I would not lose sleep over this, unless it is becoming more prominent.

 

[Thomasec]

On my NC it certainly was (is) not subtle as I noticed it (the pulsation) the very first time I shifted into 6th at 60mph. I immediately shifted back down into 5th and it went away. Then I accelerated to about 66mph and up shifted and it was not there . . . Until I let the speed come back to 60. It happens in a narrow speed and rpm range and only in 6th. I thought at the time (and until recently when this thread started) that it was just a new engine break in issue, but after 1000 miles or so, it is still there. The pulsation feeling on mine is definitely pronounced and unmistakable, so I doubt if any of you would not notice it and even have some mild concern like I do. Therefore, those that don't notice it I am fairly certain do not have the problem.

 

[gkgeiger]

On my bike (DCT) it only does it from 49-54 mph. So I just try to avoid that speed.

 

[tromba]

My bike seems ok in that MPH range in 6th. The only problem is I, too, have to downshift for any power.

 

[Thomasec]

tromba's comment just adds to my theory that it is a real problem, and not all of us are experiencing it. My guess though is 50% are, so I will be especially interested to hear what the official Honda statement will be. Note to everyone, we (who have the problem) are not talking about lugging the engine down, lack of power in 6th or suspension issues, this is a specific "harmonic" pulsation that happens on a manual transmission NC700 traveling approx. 60mph (100kph) in 6th gear on level ground (somewhat lower with the DCT version.) Unmistakable and you either have it or you don't. My current thinking (pure speculation) is that it might be related to mfg tolerances of a component in the drive train. Identifying the offending component will be Honda's job. I hope they come through as my riding buddies whom I've let test drive my (very loved) new bike have commented on it and wonder "what is up with that?"

Interesting side note . . . No official reviews have mentioned it to my knowledge.

 

[barnsls]

Thomasec is correct - if you have a bike that has the problem it is unmistakable. I suspect that many of the people who replied to this thread with comments about lugging or normal vibration or engineered in 'character' have bikes that don't have the problem (thanks to everyone for participating in the discussion - all your suggestions have been valuable). This may mean that Thomasec's estimate of 50% might be high. My bike is a manual and has the problem between 50 and 55 MPH so it's possible that the problem manifests itself at different road speeds regardless of transmission type. I also agree with Thomasec's speculation about manufacturing tolerances; because the DCT and manual versions can have the problem it would appear to eliminate the gear clusters, shafts and bearings and the clutch because they are different between the models. I guess that leaves the engine components and the wheel hubs/bearings as probable candidates. I hope to hear from my local dealer tomorrow and I will share his opinion with this thread - but it will be the local dealer's opinion, not an official Honda statement or appraisal. If the dealer agrees that the pulsing is unusual I'm hoping that he will provide Honda with the information so that their engineers will be aware that some of the bikes have a characteristic that detracts from the pleasure of riding them in normal traffic conditions.

 

[Xcellor8]

dduelin posted this in the general discussion section...

Cross posted:

"Honda announced a Stop Sell Notice on the NC700 today.

The issue is the drive chain on the bikes. All the bikes have to be inspected and if it has an D I D chain it is good to go.

If it has an RK chain it has to have RK and Japan stamped on it. Seems some have RK chains and they have failed.

My local dealer has two on the floor, one with an D I D chain and one with the RK chain.

If you have already purchased an NC700 check your chain and see what chain you have and call your dealer for info."

670cc commented that maybe there could be a connection? I do not have the RK chain in question, and I have experienced none of the symptoms. Your thoughts?

 

[Thomasec]

A very interesting development. I have RK and have the problem.

Everyone should chime in on this one.

 

[Cyclerosis]

Little Ed, I was curious whether or not the vibration was more prominent at the top of the travel of suspension. For instance, if you're cresting a hill at speed fast enough to give you that brief sensation of weightlessness. I've noticed a vibration under that circumstance no matter what speed I'm travelling. It's kind of like something's out of balance.

 

[Thomasec]

No, it happens on level ground.

 

[Little Ed]

Cyclerosis- I do not travel fast enough to get into a somewhat airborne state. The hills I am riding are very gradual transitions and are about 2 to 6 degree incline). The pulsation is prevalent when the engine is being taxed under load . ie climbing a 3 degree or more hill at 55 MPH (at 3K RPM) in 6th gear. As I crest the hill and the road levels out, the pulsation substantially reduces. It will remain very slight and virtually disaapear as I continue down the other side of the hill. As I hit my next gradual hill, the process repeats itself.

If I am on level ground and doing the same speed (55 @3K in 6th gear) and merely increase the throttle to accelerate, the increased load on the system reacts exactly the same. The harder I accelerate, the more pronounced the vibration, until the RPM (and/or speed) increase. Actually I believe it is the RPM of the engine that is smoothing out. It is not going away, but rather gives the impression of smoothing out as the imbalancing forces gradually cancel out.

Another example: Today we experienced 20MPH winds from the north. On the same sections of level road that I travel daily with moderate head winds I could easily do 57-59MPH and the bike would run fairly smoothly. Today, these strong headwinds substantially impacted the bike and I had to downshift to smooth out the pulsation. (I know, I could of taken it up to 70 but the risk/reward equation was not in my favor.

BTW- I have the DID- Japan Chain (see another thread covering chain issues and potential recall )

 

[bigjay]

I have it around 100 kph and 3000 rpm in 6th gear. Soon as i move to, say, 115 kph and 3400 its gone. My guess is the engine is labouring. Take a 4 cylinder manual car, put it into top gear at low rpm and low road speed, accelerate moderately, and it will vibrate and carry on a little too. If its something significant, I'm sure we'll find out soon enough.

 

[Beemerphile]

Little Ed, I was curious whether or not the vibration was more prominent at the top of the travel of suspension. For instance, if you're cresting a hill at speed fast enough to give you that brief sensation of weightlessness. I've noticed a vibration under that circumstance no matter what speed I'm travelling. It's kind of like something's out of balance.

Is your chain slack properly adjusted?

 

[Beemerphile]

I also agree with Thomasec's speculation about manufacturing tolerances

Given Honda's excellent manufacturing processes, QA, and controls, I will be surprised if this turns out to be the cause.

 

[Little Ed]

Chain tension is good. Have about 1800 miles on the bike and cleaned/lubed it 4 times already. This past weekend I noticed it a bit looser when lubing, so I tightened it slightly (rear tensioning bolts 1/3 of a turn- 2 flats on the nut). Went through "chain learning pains" with my first bike, so I am sensitive to maintaining chain tension. Can't wait to get my center stand to do this chore easier..expected delivery is late Nov.

 

[barnsls]

Given Honda's excellent manufacturing processes, QA, and controls, I will be surprised if this turns out to be the cause.

Never heard of V4 motors with cam problems or 1200 wings with fried alternators? Even the best production engineers have occasional problems.

 

[Beemerphile]

Never heard of V4 motors with cam problems or 1200 wings with fried alternators? Even the best production engineers have occasional problems.

Yes, I know they are not gods. I didn't say it was not the problem, I said I would be surprised. They are very good at manufacturing process control. I have been in three of their plants.

 

[barnsls]

Just got off the 'phone with my dealer. The problem with the chain (my bike has the type of chain being recalled) is that the plates were not properly hardened leading to rapid and uneven stretching of the chain. I pointed out in my original post that the problem felt like an unevenly stretched chain so I'm hoping that a new chain will fix the problem - won't know for sure until Saturday when the new chain arrives. I'll let you know what happens then.

 

[Cyclerosis]

Is your chain slack properly adjusted?

Yes, it's just under 1 3/8. Checked at 700 + miles when I lubed the chain. Thanks for the reminder though. It's due for another lube job and I'll re-check the tension.