I'd be surprised if refitting the standard can with a set of aftermarket headers does much to restore the fuelling to somewhere near correct. The biggest influence is fitting headers and thereby removing the cat'.
Like i said. I've run it with this combo for 8500miles so far and she's running very sweet indeed. maybe a little lean still, but no more so than when she was totaly standard.
I think the combination of free flowing end can and headers overwhelms the EMS which can cope with just headers replaced but not both.
I run mine with headers fitted and oem end can and it runs just fine. One day soon I will get it dyno'd with this set up.
Sickpack
Guest
Well chaps, here's the next load of info, after much time spent on phone and net!!
Akrapovic say their full exhaust system is designed and developed to run on this bike, and will cause no problems.
However they specifically say not to run a different air filter or it will run too lean!!
Armed with this info, i returned to the dealer, who admitted he wasn't aware that was what Akro state, and we agreed to re-fit the standard air filter and replace the baffle.
The bike is still under dealer warranty because they supplied and fitted the exhaust, and Akrapovic guarantee their parts for this bike. So i'm covered as far as warranty goes.
Two other dealers have different opinions, one saying they wouldn't change the down pipes, and both saying they wouldn't change the filter!
So spoke to a Dyno centre, and he says the pipe doesn't make much difference to the fuelling, but the filter does, and he agreed with my dealer that it should be fine with full Akro, and standard filter, but suggested a run on dyno to make sure. £40 well spent me thinks.
I'll report back after that and let you all know.
Thanks for all your help and interest so far.
I'm off for another guinness.
By the way, the bike FEELS great with this set up. Great in the mid range!!
Akrapovic say their full exhaust system is designed and developed to run on this bike, and will cause no problems.
However they specifically say not to run a different air filter or it will run too lean!!
Armed with this info, i returned to the dealer, who admitted he wasn't aware that was what Akro state, and we agreed to re-fit the standard air filter and replace the baffle.
The bike is still under dealer warranty because they supplied and fitted the exhaust, and Akrapovic guarantee their parts for this bike. So i'm covered as far as warranty goes.
Two other dealers have different opinions, one saying they wouldn't change the down pipes, and both saying they wouldn't change the filter!
So spoke to a Dyno centre, and he says the pipe doesn't make much difference to the fuelling, but the filter does, and he agreed with my dealer that it should be fine with full Akro, and standard filter, but suggested a run on dyno to make sure. £40 well spent me thinks.
I'll report back after that and let you all know.
Thanks for all your help and interest so far.
I'm off for another guinness.
By the way, the bike FEELS great with this set up. Great in the mid range!!
I have to admit this is all very confusing to me. How can you tell if your bike is running too lean? Does it sound any different? Is there any difference in performance? Is this just a guess?
And how can a Dyno operator make the decision on whether a specific engine is running too lean? Does he know how every manufacturer sets up their fueling and how its optimised? Or is it just a guess?
My thoughts would be to dyno a standard header/can/air filter set up and relate everything back to that as a baseline. Then whatever changes are made to the system, the relative difference to the baseline can be shown. Its then possible to make the statement that the new set up runs leaner to standard. But how do you come up with whats "too" lean just looking at a readout?
Or maybe I'm simplyfying a black art too much!
And how can a Dyno operator make the decision on whether a specific engine is running too lean? Does he know how every manufacturer sets up their fueling and how its optimised? Or is it just a guess?
My thoughts would be to dyno a standard header/can/air filter set up and relate everything back to that as a baseline. Then whatever changes are made to the system, the relative difference to the baseline can be shown. Its then possible to make the statement that the new set up runs leaner to standard. But how do you come up with whats "too" lean just looking at a readout?
Or maybe I'm simplyfying a black art too much!
http://moodle.student.cnwl.ac.uk/mo...uelSys/gasoline/fund/stoichiometricratio.html
Modern engines are usually set up to run leaner than stoichiometric but there comes a point at which things start to run much too hot to the detriment of exhaust valves and seats in particular. Equally, exhaust gas temperature is a fair indication of the air/fuel ratio.
Do we have any dyno operators in the house?
Modern engines are usually set up to run leaner than stoichiometric but there comes a point at which things start to run much too hot to the detriment of exhaust valves and seats in particular. Equally, exhaust gas temperature is a fair indication of the air/fuel ratio.
Do we have any dyno operators in the house?
By sticking it on a dyno, hence the suggestion.
A bike produces the best power when running slightly lean (but like Schtum says, it can run dangerously lean) so the bike will feel great, but may be doing damage to itself.
You can look at the spark plugs to get an idea if it is running lean, rich or about right....
A sensor is placed in the exhaust to analyse the gases present to work out if it is running at the optimum safe level.
Look down your exhaust pipe:
Dark greyish colour = Good fuelling
Very Dark/Black sooty colour = Running Rich/very rich
Light gray/white colour = Running lean/very lean
Simples....
Dark greyish colour = Good fuelling
Very Dark/Black sooty colour = Running Rich/very rich
Light gray/white colour = Running lean/very lean
Simples....
Sickpack
Guest
Look down your exhaust pipe:
Dark greyish colour = Good fuelling
Very Dark/Black sooty colour = Running Rich/very rich
Light gray/white colour = Running lean/very lean
Simples....
Yeah, thats also what the dealer said. Stick your finger down the pipe and see how much soot comes out!! Technical eh!, but apparently its a good indicator.
(make sure its cooled down hee hee
)
Yeah, thats also what the dealer said. Stick your finger down the pipe and see how much soot comes out!! Technical eh!, but apparently its a good indicator.
(make sure its cooled down hee hee
It is and it isn't.
Like the spark plugs it will give you a good indication, but....
If a bike is running fine through most of the rev range but dangerously lean in one spot then it won't show that. The soot from the good/rich part of the rev range will not burn off in the short time it spends in the lean part of the rev range.....
There's no substitute for a dyno with a wide-band lambda sensor and a dyno operator who knows what s/he's doing.
Well there is but it also involves a wide band lambda sensor a data logger and doing it on-the-fly.
Will be watching this thread with interest, just fitted my new Keihan headers to my 09 GSA which already has an Akro on it. Its first service is due in a couple of weeks so I'll ask the dealer to check it. If its too lean I'll go down the PC route. What other options are there available? And are they difficult to fit?
Tony
Tony
nharrisn
Registered user
Thanks
Harry
You are right, many people including me have done thousands of miles on GS with altered exhausts.
However were any of your bikes 08 or 09 models with the extra hp or other GS models.??
These have been built to run much leaner than previous GS models in order to get the extra hp out of the engine. It is only these models that seem to run so lean and therefore are the subject of this thread.
Wad, my current bike is an 08 GSA, 16k miles, 106hp?
It is just freeing off really well and is running with the OE air filter, I have nothing to clean the Uni filter with otherwise it would be in.
It burns hardly any oil these days even when horsed for longer periods.
Also, I would say it is running so well that there could'nt be much amiss with the fueling
I would say it is running so well that there could'nt be much amiss with the fueling
Not saying that is the case with yours (esp if you are running standard air filter) but it pulling like a train tells you nothing about the fuelling except it's not running stupidly rich.
D6
Registered user
as per adamA, a weak running bike can give the impression of running better than nornal mixture sometimes,
(usually before holing a piston
)
(usually before holing a piston
)
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