12425 - Established June, 2013 - all GRiSO, all the time...
 
HomeFAQRegisterLog in
Share | 
 

 GRiSO 1100 exhaust(?) rattles at 3500 rpm

Go down 
AuthorMessage
guzzifuzzi
Squinternotto
Squinternotto
avatar

Posts : 8
Join date : 2017-07-22
Age : 50

PostSubject: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Wed Oct 18, 2017 2:57 am

Hi,

my GRiSO 1100 with original exhaust system has an annoying rattle sound at 3200 - 3600 rpm (maximum at 3500 rpm). It changes a little if the engine is hot or cold. I dismantled the exhaust manifolds, looked at the cover where the monifolds come together but couldn't find the cause. A mechanic at Agostini in Mandello listened to the noise but wasn't either able to locate it. It doesn't seem to be a common problem.
I am sure it is not coming from the last part of the exhaust system (the school cone Very Happy ) but no evidence.
Has anybody had a similar problem?
I read in the technical description that the exhaust manifolds are double walled design but when I look into them it looks more like single wall - does anybody know if it is single or double wall?
If the manifolds are double wall maybe the inner tube is able to move and at the resonance frequence the vibration turns into the rattle sound.

Any other ideas?
Back to top Go down
davem
Grignapoco
Grignapoco
avatar

Posts : 150
Join date : 2013-12-17

PostSubject: Re: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Wed Oct 18, 2017 3:20 am

Get yourself a length of metallic tube, copper pipe would do and use it as a stethoscope to locate the source of the noise.
You can buy a engine stethoscope cheaply from ebay if you want. [You must be registered and logged in to see this link.]
Back to top Go down
Pete Roper
GRiSO
GRiSO
avatar

Posts : 5200
Join date : 2013-05-29
Age : 61

PostSubject: Re: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Wed Oct 18, 2017 3:51 am

Commonest cause for weird exhaust rattles is if the catalyser has come loose. Take it off and give it a shake.

Pete
Back to top Go down
guzzifuzzi
Squinternotto
Squinternotto
avatar

Posts : 8
Join date : 2017-07-22
Age : 50

PostSubject: Re: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Wed Oct 18, 2017 4:14 am

Hi Pete

This might be a good option to take a look at. It is my first motorcycle with cat - is it located in the central exhaust pipe behind the lambda sensor or in the entrance of the silencer?

I can follow davems hint and put my ear at the cat area. Guess what - I already own the stethoscope shown in link but I hadn't the idea using it for this purpose. I am just afraid that it will be very noisy putting the stethoscope against the silencer at 3500 rpm but it is worth to give it a try.

Thanks a lot
Back to top Go down
Pete Roper
GRiSO
GRiSO
avatar

Posts : 5200
Join date : 2013-05-29
Age : 61

PostSubject: Re: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Wed Oct 18, 2017 4:15 am

The cat lives in the front of the trombone.
Back to top Go down
beetle
GRiSO
GRiSO
avatar

Posts : 5266
Join date : 2013-09-30

PostSubject: Re: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Wed Oct 18, 2017 4:19 am

Pete Roper wrote:
The cat lives in the front of the trombone.


Taken out of context, that’s a very odd statement.

Very Happy
Back to top Go down
https://www.griso.org
Pete Roper
GRiSO
GRiSO
avatar

Posts : 5200
Join date : 2013-05-29
Age : 61

PostSubject: Re: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Wed Oct 18, 2017 4:23 am

And this from a man with a GRiSO with a pink frame!
Back to top Go down
guzzifuzzi
Squinternotto
Squinternotto
avatar

Posts : 8
Join date : 2017-07-22
Age : 50

PostSubject: Re: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Wed Oct 18, 2017 5:11 am

Hi Pete,

sorry for asking again - trombone means silencer? I am playing tuba and our trombone players don't use catalysators!?
Sometimes I struggle with the slang used here - my english isn't well enough to understand all and everything, especially the hidden jokes Question  
There is still something to learn
Back to top Go down
Pete Roper
GRiSO
GRiSO
avatar

Posts : 5200
Join date : 2013-05-29
Age : 61

PostSubject: Re: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Wed Oct 18, 2017 8:40 am

Yes, the huge muffler.
Back to top Go down
guzzifuzzi
Squinternotto
Squinternotto
avatar

Posts : 8
Join date : 2017-07-22
Age : 50

PostSubject: I found the reason for the noise   Sun Oct 22, 2017 4:23 am

Hi, yesterday I took away the muffler to see if the catalysator is jumping around inside - it wasn't, it was well fixed. But what I saw when I inspected the muffler hanging in my workshop: the stainless steel cover was bended to an oval touching the inner black part. I tried to bend it back into the round shape but without success. I didn't want to remove it completly - it is fixed in a way that it will be complicated to mount it position once it has be taken away.
So I just prepared 2 little sticks of wood and clamped them between the cover and the inner part.
The test ride was a success. After 5 km I have lost one piece of wood and the rattle came back. I repositioned the remaining stick and the rattle was off. Much better now cheers cheers cheers
I will put same oven sealing fabric between muffler and cover we use at work for oven doors. That will not burn away or start fouling. Did anyone ever removed the cover and fixed it again?

Thanks for your help

[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]
[You must be registered and logged in to see this image.]
Back to top Go down
guzziownr
Tiradritto
Tiradritto
avatar

Posts : 315
Join date : 2013-12-23

PostSubject: Re: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Sun Oct 22, 2017 6:53 am

Wooden sticks? Oven sealing fabric? This post needs pictures! Log onto the site with your smartphone and you can upload pictures using the "host an image" button. We wait... Got Pics?
Back to top Go down
guzzifuzzi
Squinternotto
Squinternotto
avatar

Posts : 8
Join date : 2017-07-22
Age : 50

PostSubject: Re: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Sun Oct 22, 2017 12:18 pm

I tried to add some pics but the links were eaten by the system. I have to try again with firefox, maybe opera is not well supported. I have observed some difficulties using opera the last days.
I travel to China for 2 weeks, then I will organize the anti-rattling material. When the work is done I will write a report.
Back to top Go down
guzzifuzzi
Squinternotto
Squinternotto
avatar

Posts : 8
Join date : 2017-07-22
Age : 50

PostSubject: Re: GRiSO 1100 exhaust(?) rattles at 3500 rpm   Sun Oct 22, 2017 12:59 pm

[You must be registered and logged in to see this image.]

The catalysator is in the first part of the muffler

[You must be registered and logged in to see this image.]

The cover touches the inner part

[You must be registered and logged in to see this image.]

A little piece of wood stops the rattle...

It looks like it works this time to add the pics.
Back to top Go down
 
GRiSO 1100 exhaust(?) rattles at 3500 rpm
Back to top 
Page 1 of 1

Permissions in this forum:You cannot reply to topics in this forum
GRiSO ghetto :: The Ghetto :: GRiSOLOGY-
Jump to: