Accelerator off/on effect.

adjust throttle cable slightly

 

Look at O 2 Sensor removal they should explain it here

 

Look into removing the Air Injection system - do a Google or Youtube search. I'll cost you next to nothing and you'll have smoother throttle response.

 

the twist grip should have some free play this should be 2-3 mm look at the twist grip two cables plastic barrels and lock nut get the free play by adjusting the inner one

 

Forgive my ignorance biggy, but doesn't the AI just burn off excess gases for emissions red tape, so removing the sensors stops the popping on deceleration and bluing of pipes, whereas the O2 or lambda sensors control the mixture at low revs by putting it into an open loop. And it's this change from open to closed loop that gives uneven running at low revs.

 

Carburetors - it's the way forward!

 

Kind of.

At low levels of throttle both the AI system and the O² sensors play their part in the throttle snatchiness; as does the standard factory fuelling map which is ultra lean.

This is how I understand it works:

AI system : The Air Injection system is only there to help the manufacturer meet their pollution targets as defined in worldwide regs but for us (in Europe) currently it is EU3.

At small throttle openings (0 - 6%) the system is operational. There is a port cast into the head just downstream of the exhaust valve; to accompany this there are chrome 'injectors' one for each cylinder, next to the spark plug. To control the operating is a solenoid, managed by the ECU and a fresh air supply coming from the air filter box.

The default position of the solenoid is 'open' and needs the ECU to close it. At small throttle openings (0-6%) the solenoid is open and therefore allows fresh air to be sucked into the AI system on each exhaust stroke of the cylinder(s). This introduces fresh air into a stream very hot exhaust gases and self detonates any unburnt fuel.

This is where the popping on over-run comes from.

O² sensors : At the same time and just down-stream of all of this are the O² sensors. On the earlier EFi bikes this also occurred at 0-6% throttle openings but there are hints that from 2014 this changed to a wider use range.

Anyway, whilst the AI is doing it's thing, the O² sensors are measuring the content of the exhaust gases and informing the ECU and fuelling is adjusted accordingly.

So, at these small throttle openings there are lots of elements working together to make the bike run as lean as possible and it this combination of elements that results in STS or snatchy throttle syndrome.
.............................................................................................................................................
It is also useful to note that if the AI system is removed IN ISOLATION, this can cause the O² sensors to read the exhaust gases as being too rich and therefore telling the ECU lean-off the mixture. Causing an already lean running bike to run leaner still

There is only one way I know of, to guarantee the elimination of STS - removal of both AI and O² plus the installation of a new fuelling map WHICH DOES NOT NEED OR LOOK FOR O² information. I chose to use Triumph Twin Power or TTP.

Hope that wasn't to boring

 

There you go, remove both as biglad says, nice one biggy!

 

Yes but you need to have a corrected map as well, or the bike won't run right. Effectively you're taking a modern-ish fuel injection system which is laden with anti-pollution crap and replacing with electronic 'carburettors'.

If you go down this road, you end up with more torque, smoother power delivery, better mpg, better throttle response and a nicer-to-ride bike.

 

Great thread - I've already learnt something however....

I have a 2011 se and after talking to the dealer they wouldn't recommend removing the Air Injection because of the cats in the down pipes. Is my dealer just trying to put me off? I'm thinking of doing this modification because I really don't like how lumpy the engine feels and runs when its hot, especially at low speed.

What do you chaps think of these:-

http://www.squaredeals-ltd.co.uk/tr...lle-thruxton-speedmaster--america-20298-p.asp

 

Hi Eric, all these kits on the market are a bit pricey in my opinion. You don't need the the plastic connectors to 'fool' the ECU into thinking that the O² sensors are still in place.

This is what you will need :

2 x Nissan Micra sump plugs, to block the holes left by the now-removed O² sensors;

1 x free download of TuneECU;

1 x OBD cable like this : http://www.triumphtwinpower.com/ttp-obd-2-usb-cable.php - to connect the bike's ECU to your laptop;

1 x new fuelling map to take account of the specification of your bike - I use TTP maps.

Now,I would strongly advise that if you plan to do any other mods, such as AI removal/change of air filter/change of exhaust pipes etc -you do it all at the same time, so that you can buy a map that will take account of ALL the changes at one go !

It needs a bit of thinking about andyou might have to spend a few bob, but you will end up with YOUR Bonny !

 

Cheers for the advice Dave. I understand what you're saying and mapping out the Lambda does makes more sense than fitting a diode to fool the ECU. I would like to get all the emissions crap off without changing the exhaust but I don't know how the OEM exhaust would cope and the worry is that I'd make it worse.

At some point I do plan to change the exhaust so my thought were to do all the Air and CO mods at once. I've got the VAG ODB cable and ECU Tune and had a cursory look at how it all works. I'm just a bit worried about ending up with something that runs worse. I'll keep an eye on this thread.

 

A bit of reassurance - when you do any work with TuneECU, the very FIRST thing you do is to read and save the existing map with all it's configurations (AI and O²) onto your computer as a default backstop option, should you ever need it.

Now, running a std. configuration (map/airbox/pipes) without O² is not something I've tried and the factory map will be looking for information from these sensors, and not getting it ! What happens then?

Most modern electronic fuelling systems have default settings, just in case a sensor goes down. This is usually not optimum operation conditions, but honestly how far away from optimum - would you even notice?

If you chose to experiment, you could save your existing map, then access it from your computer, read it and de-select AI and O² then install it into the bike. Remove the AI and O² sensors, then see how she runs?

You won't do any harm if it runs badly, just swap it straight back to std.

I doubt whether the existing exhaust will cause any harm at all if you remove the AI and O² systems

 

Steve Just out of interest can you still use a center stand with the TEC system because this will be a consideration when I do replace the pipes on mine.

Dave again thanks for the reply. I've got a week off work soon so I may spend a little time learning my way round the ECU Tune software, that's if I can pull myself off the bike

 

Who needs a triumph dealer when there's THE BIG LAD!! You never fail to suprise me Dave. You alright to service my bonny on the way home tonight???

 

Yes mate, no probs at all - you're buying the beer right?

 

Thanks for that Steve. I was thinking of the Arrow but it's not compatible with the center Stand and the price is a bit daft.

I've been having a look at TTP and I'm leaning towards a TEC exhaust, removal of AI, Air intake and filter upgrade and then remapped accordingly with one of TTP maps but it won't be for a while, I will probably do the front and back springs first and possibly the seat.

 

Crispey I do remember your thread. I'm not sure if I'll be taking it to the dealers for servicing - my mate is a time served mechanic who's always had bikes so I'll more than likely do it myself with his guidance. I'm not trusting enough to leave my pride and joy with complete strangers and pluss if I do the work myself I'm learning about the machine.