Popping on the overrun

[Old Gregg]

I've been falling in love with my new GS since I bought her 5 weeks ago. She definitely has a split personality; a pussycat in 'comfort' mode on the ESA on the motorway and an absolute lunatic in 'sport' mode on the twisties, (as some sportsbike riders on the A65 could attest after Sunday afternoon's ride home from Glasgow!).
Something I've noticed when riding 'spiritedly', (ahem), is that she pops and burbles a fair bit on the overrun. I'm quite surprsed at this because she has standard pipes including the CAT so I didn't think it would do that. Don't get me wrong, it sounds brilliant just not what I was expecting.

I'm new to the world of twin cylinder bikes as all of my others have been IL4's so I'm not sure whether it's normal or not. On my last bike, (2006 R1), there wasn't too much popping and burbling until I ditched the cat and standard cans. I assumed it was a bit of unburnt fuel getting into the exhaust and detonating but this would mess up the CAT wouldn't it?

Anyone experiencing the same sort of thing?
Can anyone explain it to a simple mechanical engineer?

 

['Nuffsaid]

Anyone experiencing the same sort of thing? YES
Can anyone explain it to a simple mechanical engineer? NO

Hope that helps

BTW - They ALL do that , on my 4th and each has done this with a standard can on.

 

[Old Gregg]

It does sound impressive when arriving at traffic lights alongside cars.

 

[Rong]

Replace the CAT with a Y piece then you'll have a massive grin each time you ride it!

 

[Dainese Brave]

All in order

....personally I think it should be mentioned in the brochures as a selling point!

 

[PhilBolton]

It pops and bangs with an aftermarket can on too -- just sounds a little fruitier - an' I like it!

Phil

 

[spencetj]

I must admit when I first heard these noises I thought it was my heavy duty chain lock banging about in the top box

I kind of worked out it must be something else when I heard the same noises and the top box was empty! I don't know what it sounds like to other road users because I nearly always wear earplugs, but glad to hear its normal at least.

I know, I know, I should take the bike back to the dealer and tell them I'm too stupid to own such a machine...

 

[WindyChuffer]

Picking up new GSA on Sunday, but this time with Remus headers and Akrapovic Carbon Can.

Carbon Can being carried over from previous GSA which was very impressive and sweet popping on overrun.

Can't wait to try the more powerful '09 bike de-catted with a free flowing 'zorst and decent can !!

 

[luckylucian]

Isn't the popping and banging caused by air being drawn into the joint before the rear can and then causing detonations.

Read somewhere about using clear silicone to seal the joint around the outside and stop the air being drawn in