Sound engineering

[Guest Mac750]

Hi

Not sure if this is a service question or an additional accessory posting . 

I need some sound advice from sound engineers. My NC750x is driving me batty I hate riding it....

I love everything about it, the engine, the adventure styling the practicality. I cannot stand the airbox induction noise it's so loud. 

Louder than the exhaust note  when sat riding the bike., I have been told this is normal. 

So I need to add sound deadening without strangling the motors power. I  must admit I haven't taken the body work off to get into the air box and I know nothing about  acoustic sound deadening but I do need to muffle it somehow as it is spoiling my enjoyment of the bike. Any advise would be great as so far I have done less than two hundred miles on it in three months preferring to use my ages old MZ instead. Can anyone help please.

Edited November 5, 2016 by Mac750
Spelling grammar error

[trisaki 2,029]

Take the panels off to get to the airbox  - if the noise is from  the front  of the no- tank then it's got to be airbox  related 

[Guest Hati]

Use earplugs.

[Guest Mac750]

I do use ear plugs it's that high pitched it gives me ear ache if I don't use them. 

I have been reluctant to remove panels as it is still in warranty but needs must.  Looking for a solution which mutes the induction but does not restrict it. 

Dealer is reluctant to take the panels off. Dealer is reluctant to do anything. Hence plea to acoustic engineers on the forum. 

[Guest Hati]

You didn't say "high pitch" before. Induction noise is a roar, not high pitched. You may have something out of place on your ride that causes the whistle... Try round up someone with an other X and swap. See what the other bike is like. Just do it at the same time, same piece of road to exclude as many variables as you can.

[Guest Mac750]

Yup it has to be air box related, my dealer must have a thing for hiring staff who have bad hearing. 

The bike does roar ( even on tick over) think Darth Vader on a nebuliser . Then get the bike up to  40 to 45 and shut off the throttle or less throttle opening and  wheeeeeeeeeeeeeeee God its horrible like scratching a pan with fingernails.

[Tex 36,817]

Didn't Brian (slowboy) offer to come and help in one of your other threads on the subject? I would take him up on it, if I were you.

 

They don't all make this noise, so there must be something wrong with your bike. It's a faff taking bodywork off, but you're not going to get to the problem until someone does just that. If your dealer won't then you're going to have to.

 

You could try asking for your money back, but as the dealer is insisting there's nothing wrong with it, you could have a massive fight on your hands. Do you have the energy for that? I don't.

 

Alternatively you could cut your losses and just part exchange it for something (anything!) else. Something that you will enjoy riding. Life's too short, matey. 

 

Edit: Your description of the noise sounds like a badly fitted hose is allowing air to be sucked through a small gap, I've heard similar noises on cars where air filter trunking has become dislodged. 

Edited November 6, 2016 by Tex

[Guest Mac750]

Hi Tex,

my thoughts exactly on all of the above. I have had to give my dealer three attempts to repair or even lift the plastics and investigate before I do anything else and I have now done that .

I have been in private conversation with slow boy and will pop over to see him on a dry weekend. ( 79miles one way ) The fixings have been marked by Honda so once I climb all over it my warranty is shot.

I will never go near that dealership again if I have a choice.  I have to be careful what I write on a public site but as a warning to others I live in Cornwall and bought a Honda. Google list Honda dealerships in the U.K. 

[Tex 36,817]

Who says your warranty is affected by your doing a job that your dealer is either incapable or, more likely, uninterested in doing? I mean, if your battery fails are Honda going to claim you caused it by looking at the air-box? All those fixing marks mean is that they were done up at the factory. Who undoes them isn't a matter of interest.

[Rev Ken 6,331]

6 hours ago, Tex said:

Who says your warranty is affected by your doing a job that your dealer is either incapable or, more likely, uninterested in doing? I mean, if your battery fails are Honda going to claim you caused it by looking at the air-box? All those fixing marks mean is that they were done up at the factory. Who undoes them isn't a matter of interest.

Agreed! ALL Hondas have marks on their fixings when new for the reasons above, but are sometimes cleaned off during the PDI. Taking bodywork off does not invalidate warranties!

[SteveThackery 3,090]

On 05/11/2016 at 23:15, Mac750 said:

Yup it has to be air box related, my dealer must have a thing for hiring staff who have bad hearing. 

The bike does roar ( even on tick over) think Darth Vader on a nebuliser . Then get the bike up to  40 to 45 and shut off the throttle or less throttle opening and  wheeeeeeeeeeeeeeee God its horrible like scratching a pan with fingernails.

 

This is not normal induction noise.  There is a fault.  I suggest you don't even think of messing with sound deadening - that's just masking the symptoms and is quite the wrong way to address a fault.  You or your dealer need to identify the cause.  If it gets worse when you shut the throttle, then it strongly suggests an air leak somewhere.

 

Also, keep an open mind about the source being somewhere else.  But if it goes "wheeeeeeee" then there's something wrong.

[Guest sykospain]

Steve is spot on - there's a fault, so get onto Honda if you get no joy from your dealer.  And please name them for us.  You're quite safe whilst we still have ( pace Trump ) at least some free speech, free from fear or favour.

[Guest New]

4 hours ago, SteveThackery said:

 If it gets worse when you shut the throttle, then it strongly suggests an air leak somewhere.

 

Or never shut the throttle?

[michael 324]

are we certain it's air box related? I recall an air box issue on a vehicle, most noticeable at "full honk," but less so at partial or closed throttle (high vacuum).

 

I know the front wheel/tire makes a lot of noise when rolling - am i out of touch by suggesting it may be something there adding to the din?

[Tex 36,817]

Can't be the wheels, dude, it does it while stationary..

 

 I think small throttle/high vacuum is exactly where air being sucked through a small gap would make a noise. Kind of like a 'wind instrument' in reverse

[embee 7,288]

Check the clips and the rubber connector between the throttle body and cylinder head. This is the joint which sees low pressure when the throttle is closed. Item 6

From http://www.bike-parts-honda.com/pieces-honda-detail-78561-78561-NC750XAG-2016-E_02-NC+750+X+ABS.html

 

 

[Guest Mac750]

Will do embee, bought an official Honda workshop book and removed all the body work and air box. Inspected the air box, induction tube, air filter cartridge and found nothing remiss. So need to think outside the box.  Sorry couldn't resist that. 

[fred_jb 10,265]

5 hours ago, Mac750 said:

Will do embee, bought an official Honda workshop book and removed all the body work and air box. Inspected the air box, induction tube, air filter cartridge and found nothing remiss. So need to think outside the box.  Sorry couldn't resist that. 

While you were inside the box - did you take the air filter out and have a good look at it for tears or loose seals? I suppose there is a small possibility that a faulty air filter could cause some funny noises, so might be worth replacing it anyway in case it has a non-obvious fault.  I put a K&N in my NC which I was happy with and while it perhaps produced a little more induction noise, it didn't make any objectionable noises.

 

Edited November 12, 2016 by fred_jb

[Guest Mac750]

Hi Fred,

yes checked everything and found something that looked like assembly oil of some sort. A sticky silicone.  ( not blow past engine oil mist)

I cleaned out the air box and inspected it and found no faults. Also the air filter was inspected and found in good order, clean and dry.  Whilst it was all apart I thought of getting a K&N but for some reason my bike makes a lot of induction roar already and I didn't wish to add to it.  I have also cleaned, adjusted and re oiled the drive chain and this may or may not have something to do with the screech going away.  It could have been a contaminated air box or cleaning the chain that has effected a result, I don't actually know, also it could be just a temporary repreave. Ether way my local dealer should have investigated the cause and not dismissed my complaint out of hand.

It cost me £48 for the  Honda workshop manual but it was money well spent.  I am still awaiting the out come of the exhaust they fitted wrongly which damaged the exhaust and also the paint on the swing arm.  

Mileage is now 1,400 miles.