Knock Knock What's There?

Lorien · Sep 13, 2016

In my NT's old age I think it is trying to develop a engine knock about 4 thousand rpm but I am not sure. I hear something that seems to be related to the amount of throttle and rpm. Less throttle more knock. I seem to remember that the bike has done this since day 1 but it does seem more noticeable over the past months. Wondering if anyone else hears this as a matter of routine.
Added some premium fuel but did not notice any effect.

Phil Tarman · Sep 13, 2016

If your "knock" were detonation, it would be worse under more throttle. Given the NT's compression ratio, higher octane isn't needed or helpful for anti-detonation.

When was the last time your valve adjustment was checked?

burgundy13 · Sep 13, 2016

Mine knocks at exactly 4000rpm - as in a pronounced rapping/thrapping engine speed harsh drumming sound, not a 'pinking/pre-ignition knock' but it is louder with more throttle and almost non-existent under a very light throttle. My bike is low mileage and, I think it has done it from new (it certainly didn't cause me concern before but it is doing so now) but it seems to be getting louder (or am I becoming more conscious of it?). Absolutely no odd engine noises at any other rpm. I don't know how this relates to your knocking noise. I was going to ask the forum if this is a normal noise? Any others aware of this on their bikes? Should I be worried?

Warren · Sep 14, 2016

I would be concerned. Take it to the dealer to be checked.

DirtFlier · Sep 14, 2016

I would take a SWAG and say Cam Chain Tensioner.

burgundy13 · Sep 15, 2016

Firstly, I apologise to Lorien because I have unwittingly hijacked his thread with my own questions and now I am unsure whether the replies are directed to my question or to Lorien. I have booked my bike in to the dealer and will let you know what transpires.

May I re-direct the thread to Lorien's original post for any answers.

Jon

RedLdr1 · Sep 15, 2016

burgundy13 said:
May I re-direct the thread to Lorien's original post for any answers.

Both posts are about knocking at the same RPM so lets just keep it all here....

Lorien · Sep 15, 2016

burgundy13 said:
Mine knocks at exactly 4000rpm - as in a pronounced rapping/thrapping engine speed harsh drumming sound, not a 'pinking/pre-ignition knock' but it is louder with more throttle and almost non-existent under a very light throttle. My bike is low mileage and, I think it has done it from new (it certainly didn't cause me concern before but it is doing so now) but it seems to be getting louder (or am I becoming more conscious of it?). Absolutely no odd engine noises at any other rpm. I don't know how this relates to your knocking noise. I was going to ask the forum if this is a normal noise? Any others aware of this on their bikes? Should I be worried?

I believer we are talking about the same sound. Now my bike long ago gave me a 19 code which is a crank position sensor I am told. Oddly enough it has not recurred in quite some time. For what it is worth the sound does seem to wax and wane. Higher octane fuel seems to have little effect. I first really noticed mine after a valve service among other things. Of course ever since that service the temp gauge indicates the engine running somewhat hotter than before. However the knock really does not seem to change with indicated temperature. Is a puzzlement.

DirtFlier · Sep 16, 2016

Some Honda V-twins emit a knocking sound at certain RPM. I've owned 3 Honda V-twins (VT500F, PC800, and NT700V) and none of them ever had an engine problem because of this noise. Some had surmised that it was minor piston slap - a piston rocking when it has to change direction. A shop can take the engine apart, mic all the parts, find nothing wrong, reassemble and you'll probably still have the noise but your wallet will be a lot thinner.

If you look at the history of NT-Owner's.Org, I don't believe there is much - if anything - on an engine "knock" leading to a problem.

RED #1001 · Sep 18, 2016

After a dealer valve adjustment in the spring, I also have noticed a louder engine noise recently.
I haven't noticed running temp. change, but I have noticed a slight decrease in mpg's (~2 mpg less) and what feels like a slight decrease in acceleration.
Are we all experiencing the same thing?

Macka · Sep 19, 2016

Mine has had the same knock at 4000-4200 for the past 64,ooo km and it has not changed.
It is also there at 2700 rpm but not quite as loudly.
I believe that it is a characteristic of the Honda "V" engine.

Macka

Warren · Sep 19, 2016

RED #1001 said:
After a dealer valve adjustment in the spring, I also have noticed a louder engine noise recently.
I haven't noticed running temp. change, but I have noticed a slight decrease in mpg's (~2 mpg less) and what feels like a slight decrease in acceleration.
Are we all experiencing the same thing?

I have not but maybe I am just not sensitive enough to notice.

burgundy13 · Sep 19, 2016

Well, my bike is back from the dealer and I have to say I am not much wiser. The dealer agrees the noise is there but his mechanic says that although it sounds 'mechanical', it is not coming from the engine internals. He suggests that it might be a resonance from the induction tract. He is satisfied it is nothing to cause concern and does not want to investigate it further unless the noise radically changes. Time to ride and try to ignore it!
Jon

DirtFlier · Sep 19, 2016

[...Time to ride and try to ignore it!..Jon]

Perhaps earplugs would help! :smile:

burgundy13 · Sep 20, 2016

Funny you should say that: I have never ever worn earplugs riding a bike in nearly 50 years of motorcycling (and yes, I do now have some tinnitus!) but I actually tried some today. I rode 200 miles with earplugs in and I have to admit that they are the cheapest bike engine overhaul I've ever known. Without hearing all manner of weird noises from the engine and transmission yet still hearing a pleasing muted exhaust drone, my Deauville was absolutely transformed. I am a convert. Now I just need to find something else to worry about on my Deauville!

swingshiftssuck · Sep 23, 2016

I have a long list of crap I worry about...give me your address and I'll send it to you!...I leave 99% of the list behind when I'm riding. Maybe that's why I enjoy the NT so much.

Rand soper · Sep 23, 2016

I find that the things I worry about never happen. The more I worry about something, the better it turns out. I should start really, really worrying that I will never win the lottery....