My CBR 600F is backfiring (I think?)

[Notj7]

Hi guys, yesterday I noticed a few things whilst riding. These have only started happening recently.

A quick throttle-off say, in first from revs > 5k, gives a bit of a pop/bang.

And when accelerating in any gear, go over 4k then keep the speed constant and there's a kind of bubbling noise from the exhaust. I don't know how else to describe it. It's not the smooth sporty noise, it's more cruiser-y.

It doesn't sound healthy really. I've had it less than a year from a local Honda dealer, only done 10k on it. It's currently at 33k miles, service less than 6 months ago. Anyone have any ideas / suggestions?
____________________
Left the forum.

[Minty]

I have a CBR 900 and rolling off the throttle whilst the engine is under load and at quite high revs (say going down a hill) will make my exhaust pop away like a good 'un.

Does it still feel okay?
____________________
My fingers smell of your mum.

[CarlosCBR]

Sounds to me like hole in exhaust or a split in the inlet manifold. Check your PAIR system is still connected properly too. you are on about the CBR125 yeah?
____________________
https://www.youtube.com/watch?v=1OPv5mDPQ14

https://www.facebook.com/carl.simmonds.7

[Minty]

His current bike is listed as a CBR600.
____________________
My fingers smell of your mum.

[Notj7]

It's an 05 CBR 600F - I'm not too good with the mechanics of it, still learning!

Is this sort of stuff covered by a warranty when you buy from Honda then?

It's mainly the gargling noise when at any revs higher than 4k I guess.
____________________
Left the forum.

[_mjs_]

Sounds like a loose exhaust to me.
____________________
Previous Bikes: 2006 Honda XR125L > 2003 Yamaha DT125R > 1996 Honda CB500
Current bikes: 1997 Kawasaki ZZR 600 E5 > 2006 Honda Varadero XL125V

[Legsy.]

A you running a standard exhaust?

My 2004 CBR 600F has been doing this ever since I changed the can a while back.

I might go for a remap one day, but doubt I'll ever be arsed for the sake of a couple of extra N.m.

[Notj7]

[DrDonnyBrago]

Lambda sensor* plugged in still?


* a thing screwed into your exhaust, just before the can.

[Fbyte]

Have the same bangs on my 2001 when closing the throttle.
Some small holes on the downpipes which I fixed using some exhaust repair paste.

Two track session later, this happens....

https://cdn.bikechatforums.com/files/camerazoom-20130306122842086.jpg

No more track for the day 8(


Check for any holes. Just after starting the bike move your hand around the pipe, you should be able to feel if there are any leaks

[Acemastr]

My '97 600F used to do this, spit flames too, but that was because of a slight gap between the exhaust join that let air in, which then hit a hot exhaust and combusted.

Looked epic
____________________
2017 KTM 350 XC-F - 2014 Yamaha R6 - 2005 Yamaha YZ125
2016 Toyota Tacoma Limited

[keggyhander]

Embrace it.

Backfiring is ace.

[Snorty]

Definitely an exhaust issue if it has just started happening. Run the bike and put your hand (carefully) in various places on the downpipes, see if you can feel any air pressure.

Preferably when cold before the headers have a chance to heat up, though they do heat up bloody quick.

I'd suspect a hole personally.
____________________
Current: Yamaha FZ1 '07 | GSXR 750 SRAD

Past: CB125TDC | TZR125 | GPZ500 | CBR600F3 | ZX9-R | GSXR1000 K4

[Notj7]

Yep, you guys were right. There's a bloody hole somewhere underneath. It's 'blowing'. I can feel it with my hand.

Took it to Honda for an opinion and the sales guy told me ballpark worst case scenario, £500 for the whole system vs best as £100 to patch it that'll "last a few years", but it'll "need a new system eventually anyway".

Also been told that this sort of thing isn't covered by any warranty. Just a little pissed that I bought it from a dealer under the premise of paying more for a safer buy, and it's got a bastard hole in it!
____________________
Left the forum.

[Snorty]

[Acemastr]

Downpipes are only £250 or so aren't they? generally anyway
____________________
2017 KTM 350 XC-F - 2014 Yamaha R6 - 2005 Yamaha YZ125
2016 Toyota Tacoma Limited

[CaNsA]

[Fbyte]

The cheapest downpipes I managed to find was around 280 (Motad stainless steel)

If the hole is not huge (like mine ), try first using some repair paste (I used Nural 300) but any one exhaust repair paste from Haldfords will do it.
It is only a temporal fix, but it was fine on mine.
No more bangs for a couple of weeks until I did a track day and the whole section where I applied the paste blow off due the condition of the pipes. (badly corroded)

[DrDonnyBrago]

[Notj7]

Looking on eBay for downpipes, I see £280... however they're for the F1, F2, F3.. so < '05 versions... anyone have any links or would one of these be okay?

Also saw about the slowness after having new downpipes fitted, seems the fix is to have the ECU completely reset because it might've been running rich from when the downpipes had the hole...

Edit: also, for cheap, they're only scraped and would be an alright temp right? https://www.ebay.co.uk/itm/HEAD-PIPE-HEADER-EXHAUST-MINOR-DENTS-SCRAPE-CBR600F4I-CBR600-F4I-CBR-600F4I-05-C-/230943891744?pt=Motorcycles_Parts_Accessories&hash=item35c5542120
____________________
Left the forum.

[Acemastr]

An ECU won't 'get used' to a particular scenario, it adjusts as and when, don't worry about that unless the new downpipes don't have a hole for a lambda
____________________
2017 KTM 350 XC-F - 2014 Yamaha R6 - 2005 Yamaha YZ125
2016 Toyota Tacoma Limited

[Notj7]

Okay, Motad have offered me part: D6HFSC, set of downpipes for my 600F, for £159.99 These hard to fit? BCF fancy walking me through it this weekend?
____________________
Left the forum.

[Bofh5]

Just soak the header nuts in plusgas.
Other than that its straightforward enough.
Fairings off obviously and new gaskets are worth fitting.
____________________
(L)users...Disk space is to good for them.

Bikes: Honda 50 / CB125-TDC / 93 CBR600 F2 (Stolen & Trashed) / 2001 SP-1 (Sold) / 95 CBR600 F3

[DrDonnyBrago]

[motad_uk]

2 years ago with loads of buyers having grief with the chinese copies- we introduced our Venom range of collectors which are the ones offered at lower prices

3 year warranty instead of 10 years for Motad but still stainless 304 but perhaps with less time spent on the cosmetics

Dont want to sell on the forum of course- and also dont want to undermine our hard working dealers

Would prefer to discuss these "offline" - pm me or email ianmcdonald@motad.co.uk