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Air Injection be gone DIY

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#1 · (Edited)
Air Injection be gone DIY – 2009 EFI Bonny/Thrux

As the mystery of the new EFI bikes become unraveled and performance opportunities explored, few subjects of discussion are as debated if not misunderstood as air Injection as it relates to electronic fuel injection (EFI). The carb boys have a lot of experience with removing it on their bikes and know that it has no affect on A/F ratio. Some believe removing AI upsets the temperature of the O2 sensors on EFI. It doesn’t. EFI changes things but not as much as some believe. AI and EFI are almost independent entities made to work together but not dependent on each other. EFI doesn’t want or need AI to operate effectively.
AI in fact needlessly complicates things and hence for a hotrodder, many of us being card carrying members, AI simply must go and what this thread is about.

First…some theory:

There are two types of air injection widely used. On automobiles, a compressor is used which has different functionality than pulse air injection widely used on new closed loop EFI motorcycles. Pulse AI gets its name from the engine firing and exhaust pulses. When pistons go up in unison on a vertical twin for the exhaust stroke, this creates an air percussive pulse (wave) out of the combustion exhaust ports with velocity and momentum based upon no. of pulses per minute i.e. one half of engine RPM e.g. 4 cycle. In a closed volume, if an open orifice is upstream of this exhaust wave or pulse e.g. air injection tube….with a fresh air source available e.g. airbox, this draws...due to vacuum ...not injects (which would be positive pressure) air into the injection tubes which then is drawn into the headers to join the flow of pulsing exhaust air being emitted from the exhaust ports. So air is really drawn by vacuum into the air injection tubes, not injected under positive pressure per se…hence air injection is really a misnomer. This additional cooler air supplemented to expulsion of fuel from the exhaust ports into the headers when the throttle is closed in combination with hot headers due to combustion creates a more complete burning of fuel for reduced emissions.

The ECM only energies the solenoid to allow air into the exhaust ports at small throttle openings but also senses its presence by virtue of it solenoid resistance. The solenoid registers 20 ohms of resistance when measured with a multimeter. Without a complete circuit with resistance, the ECM will throw a code and initiate a check engine light (CEL). Both an open circuit and shorted circuit have been tried and each result in a CEL on the new EFI bonnie.

Some inquiring minds may want to know how substituting a resistor satisfies an ECM. Pretty much all interfacing components with the ECM are either fixed or variable resistors. This is how the ECM processes its information. A solenoid is a linear motor with an electromagnet comprised of a helix of wire...in effect, a resistor not unlike the ceramic covered wound wire resistor used for this DIY to replace it. Difference is is how the energy is dissipated. Basically an ECM is a microprocessor with a number of integrated MOSFET’s. MOSFET’s are semiconductor transistors used for voltage comparator circuits. ECM’s contain thousands of these decision making devices. The way AI works is…the the TPS tells the ECM the rider has let the throttle return to idle. O2 sensors go into open loop and don’t talk to the ECM which defaults the A/F mixture to a baseline map based upon information from the air temp sensor. The TPS in idle position causes the the ECM to send current to the solenoid...about .6 amps…to engage the valve and draw air from the intake into the exhaust ports. During this time the ECM evaluates the voltage due to change in current and compares it to a programmed upper and lower limit based upon MOSFET selection. If the voltage is too great or too small, it will gate the current to deploy a CEL and reset the A/F map to limp mode or open loop. That is how a circuit can both operate a solenoid and also simultaneously detect proper amount of voltage for upper and lower limit. By substituting a resistor, the circuit when activated by the ECM will still compare voltage however will no longer effect any mechanical change i.e open a valve…as the ECM interprets the resistor as a solenoid. A simple calculation suggests that a 50 ohm resistor will reduce current to .24 amps = 2.88 watts of power which will be dissipated in terms of heat versus work done to move an electromagnet opening the valve. Choosing a 10 watt 50 ohm resistor, not only reduces current still acceptable to the ECM, but also emits a modest amount of heat energy easily contained by the relatively large heat sink based upon its intentionally oversized 10 watt thermal mass capability.


OK…how to remove AI from EFI bonnies:

To begin…Richard and Dick need to be credited with a DIY to remove the gas tank on EFI bikes seen here:

http://www.triumphrat.net/twins-tec...l-and-cam-cover-replacement-lots-of-pics.html

Further, Dick is to be credited with the first to my knowledge to both remove AI and add a Power Commander III to a new EFI bike…Dick has two new EFI bikes in this configuration in fact. So Dick really started the ball rolling with removing AI initially. One of the things we have learned since then is…you don’t need a Power Commander to remove AI. Many owners started taking the AI’s off EFI bikes either with the base map or one of the optional maps. Some got CEL’s because they went a step further and removed all the plumbing associated with AI including the solenoid. I like clean so that means all the plumbing must go.


Let’s get started.
First remove the tank…how it looks with the tank off and AI plumbing in place
Most of the stuff shown in the picture will be removed:



Next unplug the large hose that draws air from the air box.

 
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#612 ·
The Kit

Got a few things from British customs one being the AIK, got a few questions:
1, There are 4 nipples, where do they go?
2, 2screw type things one with two copper looking washer/gaskets
3, One other piece?

I can only see where you used one of these items and then you use a resistor that is not included in the kit which by the way is extremely rare in Canada (as in I can't find one......No Radioshacks here), • Online, backordered in US Radioshacks!!!
Have looked all over.

BC sent me to this site off their site to use your instructions!!!

Have asked them where their instructions are!

Hope you can help,

Thanks,
Carl

P.S.
I will also be doing the Airbox removal and the Bomber pipes at the same time.
 
#615 ·
Got a few things from British customs one being the AIK, got a few questions:
1, There are 4 nipples, where do they go?
2, 2screw type things one with two copper looking washer/gaskets
3, One other piece?

I can only see where you used one of these items and then you use a resistor that is not included in the kit...
Answers:
1 If you have a bike with carburators they are used to block the ports that are on the carbs. If you have an EFI bike you don't use them.
2 The threaded plugs are installed in the hole left by the SAI injectors when you remove them. The SAI injectors are next to the spark plugs.
3 The larger rubber plug goes in the hole in the left side of the airbox after you remove the tube that goes to the SAI valve body.

As for the resistor question: I have no idea who ships to Canada, but there must be more than Radio Shack as a source. Personally I would skip the resistor and go the Tune ECU route as you will most likely be headed down that path anyway based on the mods you're planning.

And one final thought: if I might be so bold and humbly suggest you grab a delicious La Fin du Monde and spend an hour going through this thread. You do have a lot of mods you are planning and there is a lot of useful info you will miss out on if you only read my abreviated response above.
Good luck.
 
#618 ·
Also note that since this thread was started things have changed somewhat.

We've found that a much higher value resistor will also fool the ECU adequately. This means a much smaller resistor that can be fitted into the existing solenoid connector. Higher ohmic value=less heat generated=smaller physical size resistor.

We can also use software such as TuneECU to do the MIL light disabling, avoiding any sort of resistor.

Details of resistor values and fitting method on this post:

http://www.triumphrat.net/twins-tec...ps-from-triumph-twin-power-7.html#post2157299
 
#623 ·
Resistor Options



Forchetto, Thank you for providing us with your on going support, I couldnt have done with out reading your posts. Cheers!
Today I have taken off my AI. I went to my local Radion Shack for 470 ohm 1 watt Resistor but they don't have them. I have found few online but there are many different types within the above specs i.e. 470 Ohm 1/2 W 5% resistor or 1/4 W 5% or some say carbon film or metal film resistor,, Can you kindly provide some guidance re this?
 
#619 ·
O by the way just a little thing, whenyou bend backwards and forward, the air tubes[Work harden]. squeeze the tubes tight just below,,,,,,,,,,bending, with needle knose plyers,Why? I used that trick years ago,taking apart steel air lines,noticed slivers of steel inside pipe, from break, would not be good in comb chamber
 
#620 · (Edited)
It needs a simple 13mm offset ring wrench for tube removal without damage:



The AI port doesn't go into the combustion chamber, however it ends up very close to the exhaust valves as can be seen towards the end of this excellent borescope video by Alighieri, so yes, any metallic debris in there is best avoided:

http://www.triumphrat.net/twins-tec...dmaster-tor-header-borescope.html#post2460079

This is a still from that video, the AI inlet can be clearly seen :

 
#621 ·
I'll second Forchetto's suggestion of not bending the tubes. All you need to do is pop the clip off that secures the flexible hose to the metal extension tube. I used a small screwdriver. Then you pull the hose off and use the proper wrench, as mentioned above, to take it out.
 
#627 ·
anjmsar9 asked about resistor values so I assume he already knows about other alternatives:

The best one would be removal of the entire system and disabling the MIL light by using software such as TuneECU. The other is, as you say, leaving just the solenoid in place.
 
#635 ·
Thanks to everyone that replied. I did read a lot of stuff on here and did do all the mods I still cannot get the MIL Light out! Will take a while maybe this weekend to use TuneBoy again, It doesn't like the cold (computer and Bike battery) need to put the heater on for a while.
I did ask a few more questions and let people know how it went etc. and cannot find where I posted it lol.

Everything seems fine. did manage a test drive and there was popping etc. on decel,
looks like I will have to take the pipes off and put more of the red stuff in there to seal it better!

the pipes look and sound terrific, there was a definite increase in power I didn't notice the snatchiness so it could be better, it was pretty cold, Canada eh, lol.
 
#637 ·
On my 2012 T100 I just installed BC Sleepers and used their AI removal kit to take off all the AI including the solenoid. My intent (for now) was to get a dealer re-map after the install which I presumed would turn off the expected error light.

Got the re-map this morning, but the dealer said I have to put the solenoid back on to turn off the error light. He also said putting it back on now may or may not turn off the light, and I may or may not have to get mapped again.

I asked him about unchecking/disabling the SAI when they loaded in the map, which he said they did, but I still have to have the solenoid in place to keep the error light from coming on.

That sound right? I didn't leave the solenoid on or add a resistor as I thought unchecking SAI in the new map accomplished the same thing (no MIL). Dealer said that's how they always do it, and never get an error light when leaving the solenoid on (and I'm thinking "well, yeah").

Have also noticed since that re-map this morning, that the bike doesn't start like it used to...takes two or three pushes of the starter button before it turns over, and won't stay running unless I hold on the throttle a bit or pull out the assist, which I've never had to do before.
 
#638 · (Edited)
None of what your dealer said is true. You don't need to leave the solenoid in place to turn off the check engine light. Many, many people on this forum (including me) have proven that true. He simply didn't do it correctly. I would go back and tell him you've researched it and there is absolutely no reason to leave the solenoid on the bike. If he says no, I wouldn't trust him to service my bike.
 
#639 ·
@ REMLEY: your dealer is talking absolute crâp !!

Once you have loaded your new map with the SAI box unchecked,the EML will not light up with the solenoid removed.

That's the whole point of doing it !!!

I wouldn't trust someone who doesn't know this, or is lying to me about it.
 
#642 ·
Thanks to all for the input. I've been reading here for quite some time before I did this, so I felt the dealer was wrong as well, but I'm still just enough apprehensive about my own computer expertise that I elected not to escalate it to a big argument with him.

I think I'll put the solenoid back on to satisfy the light for now. Down the road I was planning on more of the TTP recommendations which is when I planned on taking the plunge with TuneECU and doing the mapping myself. Just might move that time-table up some.

Thanks again :)
 
#646 ·
Try the Arrows maps (or the OEM "aftermarket" maps). You may need to modify it by disabling the SAI (which just prevents the MIL light showing up, if the SAI had been disconnected).

The only "perfect" map for your bike with that config is the one when you get it dynoed and custom tuned. Otherwise maps such as the Arrows may be sufficient.
 
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