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 Post subject: backfire 08 Uly
PostPosted: 28 Oct 2009 20:33 
My uly backfires big time on over-run. The can has air leaks through at least two rivet holes and a couple of tiny splits - my question is - are these leaks enough to cause a lot of backfiring :?:

and inlet seals - I know often get replaced for this kind of reason - can any one recommend a supplier of top quality seals.

cheers


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 Post subject: Re: backfire 08 Uly
PostPosted: 28 Oct 2009 20:35 
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proff. patpending
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Current ride: Victoria Sponge
Location: Bristol - Gateway to all things good
Need to reduce the fuelling at high revs / closed throttle

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 Post subject: Re: backfire 08 Uly
PostPosted: 28 Oct 2009 20:46 
pash wrote:
Need to reduce the fuelling at high revs / closed throttle


you are probably right but air leaking in does cause this kind of problem. I am trying to do the easy stuff first ;)


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 Post subject: Re: backfire 08 Uly
PostPosted: 28 Oct 2009 21:16 
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proff. patpending
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Current ride: Victoria Sponge
Location: Bristol - Gateway to all things good
Exhaust bandage and paste for you then my lad...

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 Post subject: Re: backfire 08 Uly
PostPosted: 29 Oct 2009 10:18 
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shudnobeta wrote:
My uly backfires big time on over-run. The can has air leaks through at least two rivet holes and a couple of tiny splits - my question is - are these leaks enough to cause a lot of backfiring :?:

and inlet seals - I know often get replaced for this kind of reason - can any one recommend a supplier of top quality seals.

cheers


I can only answer for the first bit: I had, initially, a couple of pinholes in a Honda exhasaust system. I say initially because after a couple of good backfires as I was riding down Portsdown hill there was a bloody great hole! From memory the backfiring reduced when there was a big hole! So, yes a small air leak can cause a backfire.

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 Post subject: Re: backfire 08 Uly
PostPosted: 29 Oct 2009 18:15 
iwoo9 wrote:
shudnobeta wrote:
My uly backfires big time on over-run. The can has air leaks through at least two rivet holes and a couple of tiny splits - my question is - are these leaks enough to cause a lot of backfiring :?:

and inlet seals - I know often get replaced for this kind of reason - can any one recommend a supplier of top quality seals.

cheers


I can only answer for the first bit: I had, initially, a couple of pinholes in a Honda exhasaust system. I say initially because after a couple of good backfires as I was riding down Portsdown hill there was a bloody great hole! From memory the backfiring reduced when there was a big hole! So, yes a small air leak can cause a backfire.


.... at last a concise and informative repost ...... where the king of such like :maz: :?: ........ when u need him :twisted:


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 Post subject: Re: backfire 08 Uly
PostPosted: 29 Oct 2009 18:22 
A small air leak will cause the exhaust to pop and backfire as already said by others and if you have small holes/cracks then im sure thats the problem but over fueling on overrun is also a cause but less likely from what you have said


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 Post subject: Re: backfire 08 Uly
PostPosted: 29 Oct 2009 23:05 
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proff. patpending
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Current ride: Victoria Sponge
Location: Bristol - Gateway to all things good
SNB wrote:
.... at last a concise and informative repost ...... where the king of such like :maz: :?: ........ when u need him :twisted:


All non-standard exhausts I have seen on XBs have resulted in popping.

The Remuses I have seen have had no leaks (you can't get into them), and they pop cos there is less back pressure, they certainly do it more without the baffles.

The fuel injection system on a Buell has no clue how much airflow is going into the engine, it meters fuel based on throttle position and engine speed, not flow as a carb does. When you are in the over-run, you are in open loop, so it can't even correct the fuelling (bit of a lie cos it has Open Loop Learn enabled - but I don't think it works very well when the engine speed is changing rapidly) For this reason, a change in flow due to a change in exhaust is not catered for.

So, I challenge you to stop the popping by coating the exhaust with GunGum...

And if you need intake seals, get some HDB ones.

:twisted:

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