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Vibration/pulsing at 50 - 55 MPH in 6th

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mike5100 said:
You could always try some rubber washers under all the footpeg mounts?
Mike
Click to expand...

I may try that in the near future. I can now say that the thrum thrum at those discussed speeds is now very slight, it is still there but reduced greatly after the dealer respecced the mounting plate bolts for the footpegs. Also, lifting 1 (one) foot off the pegs (left or right) seems to make the thrum thrum go away, at least for me. so I guess it is a weird cylindrical harmonic between the two footpeg mounting plates and the rest of the bike, where the circuit completes with the riders body. (that sounds so crazy). I am 250ish. maybe it is a certain size rider? haha, grasping now I guess.

I like the rubber washer or maybe another material under the footpeg plate mounting bolts idea tho, now that I feel like it is a mechanically felt perceptive thing.
phipun
 
The saga continues. I put the bags on the bike for the first time (the brackets etc. have been there since the new chain was installed - before the pulsing problem was 'solved' - but I haven't actually put the bags on til now) and the pulsing came back - exactly like it was before I tightened the footpeg mounting plate bolts and 'solved' the pulsing problem. Removing the bags again made the pulsing go away. I guess that this confirms that the pulsing is a resonance issue with the footpeg mounting plates (the lower bag brackets mount to the end of the plates and the presence of the bags must alter the natural frequency of the plate/bracket assembly). I suspect that bracing the rear of the plates in some way will solve or reduce the problem with the bags mounted but I'm getting fed up with the whole thing - I should have gone with my heart and bought a Street Triple instead of going with my brain and buying an NC. Anyone have a nice Street Triple or Tiger 800 they want to trade for my NC?
 
I don't have this problem, so I haven't invested much time in trying to understand it, but if it is a resonance then it just needs to be broken up. Adding weight should lower its frequency. Finding another point to ground it out (bolt it down) might prevent it altogether. I would look for a place under the aluminum casting where I could place a lead weight that would press it between the casting and a frame rail. I would start with plumbers' putty or modeling clay in order to find out how thick and where the piece of lead needed to be. Then I would size it for a few thousands interference when bolted tight. My 40 ton shop press can make a piece of lead be any shape or thickness I need it to be.

There are lots of good bikes with an unfortunate problem or two. I am going to bet that the 800 and the ST have a hole or two in their swiss cheese. If you basically like the bike, I'd say stick it out and solve the problem. Eventually someone will and you can incorporate their solution. I have fixed a lot of shortcomings on airhead BMW's because I basically like the machines. When I was considering a KTM 990 SM-T I had already read up on the nagging items that needed to be addressed. With the NC, nobody knew what the issues were going to be. Now we are finding out and we just need to stay cool and solve them. Then we will have the great little bike that we thought it and bought it to be.
 
I don't have the problem either, so I am unable to troubleshoot but... has anyone suggested or checked the bolts where the engine mounts to the frame? My last bike, some owners reported that those bolts loosened during break-in and properly torquing them fixed some vibration issues. Worth a shot.

trey

*edited to add* The real shame of this is Honda and their dealers not stepping up to solve the problem for you all. This is obviously a bike specific issue, if this was the normal 'character' of the bike, we would all be experiencing the same pulsations/vibrations.
 
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Beemerphile said:
I don't have this problem, so I haven't invested much time in trying to understand it, but if it is a resonance then it just needs to be broken up. Adding weight should lower its frequency. Finding another point to ground it out (bolt it down) might prevent it altogether. I would look for a place under the aluminum casting where I could place a lead weight that would press it between the casting and a frame rail. I would start with plumbers' putty or modeling clay in order to find out how thick and where the piece of lead needed to be. Then I would size it for a few thousands interference when bolted tight. My 40 ton shop press can make a piece of lead be any shape or thickness I need it to be.

There are lots of good bikes with an unfortunate problem or two. I am going to bet that the 800 and the ST have a hole or two in their swiss cheese. If you basically like the bike, I'd say stick it out and solve the problem. Eventually someone will and you can incorporate their solution. I have fixed a lot of shortcomings on airhead BMW's because I basically like the machines. When I was considering a KTM 990 SM-T I had already read up on the nagging items that needed to be addressed. With the NC, nobody knew what the issues were going to be. Now we are finding out and we just need to stay cool and solve them. Then we will have the great little bike that we thought it and bought it to be.
Click to expand...


Totally this. :)

No matter how bad the weird pulsing thing gets (well, jeez, I surely hope it doesn't get any worse for me than it already is, gulp...lol) I will soldier on, and try to come up with some solutions.

My brand spanking new BMW F800ST was, for me, the Mother of all wretched problems, one after another after another. Many many other F800 owners are thrilled to bits with them, and I would still be too, if it weren't for my damned luck of the assembly line draw, sigh. :(


The NC pulsing is a blessing, to only have to deal with. (again, for me. I absolutely sympathise with and understand those who just can't stand it)
 
I was just going to say the same myself Trey. This thread is 220 posts long and there's a similar length thread on the European NC700 forum. I can't believe Honda's marketing department don't monitor forums, so hopefully they will be asking their engineers to sort it.
Mike
 
The CBR250R had some little engine rattling at about 4K-5K rpm. It's a very wide spread problem (or annoyance) for many owners. It started for me after about 5000 miles. It's not effecting the performance of the bike at all. Everybody complained but Honda and dealers all have been turning a deaf ear. Nothing has been done for 2 years now. Unless the problem is causing performance issues, failure, or injury, I don't think Honda (or anything company) would stay up at night, thinking about it.
 
You may be right Tony, but in this day and age of owners (and potential owners) being able to communicate amongst themselves, a manufacturer ignores what they are saying at their peril. I would imagine that the quality issues that BMW have had in recent times would not have become as widely known if they weren't exposed on forums. Where the problem highlighted is fundamental, then the manufacturer is probably going to try and tough it out, but where it's something trivial (like a harmonic vibration issue), you'd hope that they'd ask for a couple of bikes that are doing it and get a couple of their engineers to sort it in a couple of hours, then make a production line change. In fact that's probably what they are doing and we'll never know, unless the eagle eyed spot some changed part numbers.
Mike
 
Completely agree, Mike. With internet and forums like this, consumers are able to share their experience and band together. If the same problem is being seen enough times, it might be accepted as fact or truth. A lot of time, it's the "perceived" customer service that matters, even though nothing would have changed in the end. I hope Honda would go that extra mile to look into the problem and "attempt" to fix it. Especially if this is might be as simple as inserting a rubber spacer in there to dampen the harmonic vibration, much like the little rubber band you put on a tennis racquet to dampen the impact/vibration when striking a ball.

I wonder, somewhere down the line, if sending a petition from this forum to Honda would make a difference?
 
treybrad said:
I don't have the problem either, so I am unable to troubleshoot but... has anyone suggested or checked the bolts where the engine mounts to the frame? My last bike, some owners reported that those bolts loosened during break-in and properly torquing them fixed some vibration issues. Worth a shot.

trey
Click to expand...

I've actually though about this too, that maybe the engine mounting bolts should all be loosened up, then all retorqued.
I don't have the problem (I guess), so I can't test this on my own bike.

Greg
 
barnsls said:
The saga continues.......
Click to expand...

I also continue to see the vibration progressively worsen as time goes on. Strong levels of vibration are now solidly felt through the entire bike in 4 th gear (or higher) whenever taxing the engine below 3500RMP. Originally, when I bought the bike, my problem was only felt in 6th gear, when below 3000RPM and, there was absolutely no vibration at any other gear if the RPM was above 2500 RPM!. Over the past week or so I have some vibaration in 3rd gear when climbing hills, recognizing that I live in southeast Missouri with very small hills---not the Apalacians, nor the Sierra Mountains, etc.

Yesterday I had my brother-in law ride my bike several times for well over an hour and a half, and he also felt the vibration. Being an auto-mechanic for 35 years, he did not seem to think it was an engine misfire, and not being able to compare my bike to the same model that "ran smoothly", he was not able to clearly define it as a problem. With riding experience for well over 45 years and owning multiple bikes that had various forms of vibration, he recommended running at the higher RPM, which is where numerous folks have been coaching us. Given his perspective I am not ready to take it 165 miles to the dealer to have them set and stare at it for several weeks and then return it with the same issue.

Those monitoring this message section of the forum may recall that I checked compression and valve clearances at 2000 miles- both were well within spec. Yesterday I confirmed "hot" compression values and they are still strong at 250 PSI. I do not see any reason to pull the valve covers off again at this point in time. I will continue to ride (more frustrated than ever), because it seems that it will just continue to worsen over time/miles.

In the interim with almost 3200 miles on the bike, I plan to look at both the ignition spark and then the fuel injection system. Today I ordered a secondary probe (from Pico) for my O-scope to monitor the high voltage spark voltage signal. I they are very similar in amplitude (voltage level) and shape, it will be time to scope both injector gating signals from the computer. If they also are similar in pulse width and shape at varying RPMs, I guess I will se if I can test both injectors' flow as well. Anyone have any experience with injector testing, in the event I get to that point?
 
Well, maybe we can sort some things out now : if it's getting worse, then it cannot be due to some structural flaw, to an inherent design error. The same conclusion can be arrived at from a different angle, namely that some machines have the problem, others not. But, since the problem is definitely not restricted to some isolated cases, it might be possible that some component could, as was with the drive chain, have different manufacturers, and one of them has quality issues. Or, that at some more involved stage of the assembly, some item has been systematically overlooked. Again, if it's getting worse, caution is advised, sudden failure being a possibility.

One thing that could be tried, that missing bolt on the radiator, i know that's how it's meant to be, but tightening up there cannot hurt.
 
I think this problem is the chains...

Have anyone notice how long the chains are on our NC700x??? How many links are there... Anyone know?
 
Beemerphile said:
That is pretty normal.
Click to expand...

I notice this when I bought the bike almost 2 weeks ago, taking off from the dealer and eventually shift into 6... Feel like the chains is bad...

I even check and make sure bike has good chains before I bought it... Service manager that I talked to before I bought the bike knew all about the recall and everything, my bike came originally with RK chains that he swapped out with DID japan chains..
 
LA_NC700X said:
I notice this when I bought the bike almost 2 weeks ago, taking off from the dealer and eventually shift into 6... Feel like the chains is bad...
Click to expand...

My first reaction when I picked up my bike was that the chain was bad. Even after the chain was replaced due to the recall the bike still felt like the chain was bad. I improved the situation by making sure that the bolts holding the footpeg plates to the frame were properly tightened - mine were barely snugged down. After tightening them to the correct torque the bad-chain-feeling was reduced to an almost imperceptible level. I think that the footpeg mounting plates vibrate in sympathy with the motor and the chain at a particular rpm and road speed and the tightness of the mounting bolts affects the magnitude of the vibration. However, when I later installed the side bags the bad-chain-feeling came back - removing the bags made the feeling go away again. If you have the bags installed try taking them off and go for a ride to see whether that changes anything. If you don't have the bags installed try riding at the problem speed with your feet off the pegs - if you don't feel the bad-chain thing with your feet raised off the pegs try checking the mounting plate bolts for tightness.

Steve.
 
After a couple of weeks I finally got the time to get off city streets and on the back roads only to discover I now had the vibration and pulsing feeling in the pegs at 50-55. I have not had this before now. I felt it in both pegs but it was definitely more prominent in the left peg. I also found that I felt it more with the arch of my foot on the peg than with my toes on the peg. I could feel the same distinct vibration at the same RPM at lower speeds/gears but the pulsing was only at 50-55. The vibration was subtle at lower speed/gears. The pulsing had a steady pattern and intensity.
This was my first time at that speed since installing the center stand so I started there. Loosened and retightened the exhaust hanger bolts. I didn’t tighten them as much as I previously had. Loosen/tighten the center stand retainer bolt. Then based on advice I’ve read here I loosened and tightened the 2 bolts per side for the peg mounts. The peg bolts weren’t very tight. I’m using regular hand hex wrenches as I don’t have socket hex wrenches to use with a torque wrench and I don’t have a manual yet to get the specs so I snugged them “good-n-tight”. Results are no more pulsing and general vibration is back down to what I would consider as normal.
 
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