Cooling down Noise in the silencer when the bike is switched off? - xBhp.com : The Global Indian Biking Community

rennycornelius · 11-06-2008, 08:08 AM

After a ride of about 10-15 kms or even less in my APACHE RTR FI, when i switch the bike off the silencer starts makin a "kat" "kat" noice.......

the same noice my HONDA DIO also used to make,i experienced this in the bikes sporting the black end cans only(CBZ,RTR,P180,DIO).....

one auto mag also clarifies this as the "cooling down noice" of the silencer...............

any ideas whats this noice is all about........????

Aryan · 11-06-2008, 11:13 AM

Thread approved and moved.

I don't have much idea what's happening inside the silencer/ exhaust system but even my P-200 makes this noise, but strangely the P-180 Classic did not emanate this noise..

11-06-2008, 11:22 AM

Some metals, when cool, make such sounds. This is completely normal, and nothing to worry about

Old Fox · 11-06-2008, 11:41 AM

All metals expand when heated and contract on cooling and metals in sheet form do this all the more and quicker too because of the larger surface involved. Since exhaust pipes are invariably made from sheet metal which heats up while the engine is running, it cools and contracts rather rapidly once the engine is off. This contraction makes the 'kit-kat' sound. All pretty normal.

PS: check out a similar sound from your electric iron once you switch it off

Technocrat · 11-06-2008, 03:04 PM

I got this noise in all my bikes i.e. P180 DTSi V1(chrome silencer), ZMA & RTR except for the classic 150(which i didn't ride fast

)

From what I remember its the sound from the Catcon in silencer which is due to contraction.

SO all the bikes with catcon will have this sound & the older ones without catcon wont

rider_richards · 11-06-2008, 03:06 PM

thats a just normal bro...

lets keep on riding..

winzeee · 11-06-2008, 03:34 PM

Zma make the loudest noise i guess BTW no worries its normal .

W

Puneet1 · 11-06-2008, 04:24 PM

2day il check if my bike also mkes this noise . i thought only cars make it cos my maruti also used to have tak-tak sound

SARAB_FI · 11-06-2008, 07:43 PM

this kat kat noise is coming frm the engine side in my bike (guess its the cooling of engine tappet).

regards
sarab

sameer_hyd · 11-06-2008, 08:08 PM

@Oldfox: Bang on.......Uneven expansion of solids....more so, the part of the silencer near the engine is hotter than at the end of the silencer.....So more the heat, more the expansion...

11-06-2008, 08:08 AM	#1 (permalink)
rennycornelius . Join Date: Sep 2008 Location: Indore Posts: 2,934	Cooling down Noise in the silencer when the bike is switched off? After a ride of about 10-15 kms or even less in my APACHE RTR FI, when i switch the bike off the silencer starts makin a "kat" "kat" noice....... the same noice my HONDA DIO also used to make,i experienced this in the bikes sporting the black end cans only(CBZ,RTR,P180,DIO)..... one auto mag also clarifies this as the "cooling down noice" of the silencer............... any ideas whats this noice is all about........???? Attached Thumbnails

11-06-2008, 11:13 AM	#2 (permalink)
Aryan Senior Member Join Date: Jan 2006 Location: New Delhi/ Shillong Posts: 18,274	Thread approved and moved. I don't have much idea what's happening inside the silencer/ exhaust system but even my P-200 makes this noise, but strangely the P-180 Classic did not emanate this noise.. __________________ ...in search of that perfect world - My Travel Blog :)

11-06-2008, 11:41 AM	#4 (permalink)
Old Fox Senior Member Join Date: Oct 2007 Location: Noida Posts: 669	All metals expand when heated and contract on cooling and metals in sheet form do this all the more and quicker too because of the larger surface involved. Since exhaust pipes are invariably made from sheet metal which heats up while the engine is running, it cools and contracts rather rapidly once the engine is off. This contraction makes the 'kit-kat' sound. All pretty normal. PS: check out a similar sound from your electric iron once you switch it off __________________ I don't let my motorcycles interfere with my motorcycling... Join xBhp On

11-06-2008, 03:04 PM	#5 (permalink)
Technocrat Senior Member Join Date: Sep 2003 Location: New York Posts: 884	I got this noise in all my bikes i.e. P180 DTSi V1(chrome silencer), ZMA & RTR except for the classic 150(which i didn't ride fast ) From what I remember its the sound from the Catcon in silencer which is due to contraction. SO all the bikes with catcon will have this sound & the older ones without catcon wont __________________ Racing Throttle Response Last edited by Technocrat; 11-06-2008 at 03:10 PM.

11-06-2008, 03:06 PM	#6 (permalink)
rider_richards sPeEd mAtTeRs !! Join Date: Sep 2008 Location: Bangalore Posts: 7	thats a just normal bro... lets keep on riding.. __________________ *" The best modifications cannot be seen from the outside* "**

11-06-2008, 11:22 AM	#3 (permalink)
yamracing Guest Posts: n/a	Some metals, when cool, make such sounds. This is completely normal, and nothing to worry about

11-06-2008, 03:34 PM	#7 (permalink)
winzeee Senior Member Join Date: May 2008 Location: Cybertron Posts: 684	Zma make the loudest noise i guess BTW no worries its normal . W __________________

11-06-2008, 04:24 PM	#8 (permalink)
Puneet1 Aut viam inveniam aut faciam Join Date: Apr 2008 Location: Gurgaon Posts: 1,710	2day il check if my bike also mkes this noise . i thought only cars make it cos my maruti also used to have tak-tak sound __________________ Bi-xenon Projector Hid up for sale ! click

11-06-2008, 07:43 PM	#9 (permalink)
SARAB_FI RtRing arnd!! Join Date: Oct 2008 Location: NEW DELHI Posts: 211	this kat kat noise is coming frm the engine side in my bike (guess its the cooling of engine tappet). regards sarab __________________ BIKING ??? " A RELIGION "

11-06-2008, 08:08 PM	#10 (permalink)
sameer_hyd Gud to be back Join Date: Sep 2008 Location: Hyderabad Posts: 59	@Oldfox: Bang on.......Uneven expansion of solids....more so, the part of the silencer near the engine is hotter than at the end of the silencer.....So more the heat, more the expansion... __________________ Ride rash fool......And make Darwin proud.....!! Last edited by sameer_hyd; 11-06-2008 at 08:12 PM.

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