Freez, do you think that this oxygen is the main reason responsible for excessive backfiring in the exhaust?

Tanks CAP!:icon_thumleft:

I�ll try and report heare...

By!

Ais Removal
 

I removed and blocked my AIS /valve , pipes.I tune motor vehicles.On A car its clled an EGR valve.
And as a Race car builder,we remove this valve for better performance.
It made my bike a bit richer,and it wheelies better now.I have Akropovicks fitted and a K&N Airfilter.
See this link.. http://en.wikipedia.org/wiki/Exhaust_gas_recirculation
:rockwoot:

I am not trying to prove who is right or who is wrong I am not like that at all, I just need to clear up some points.

A.I.S stands for Air Induction System & must not be confused with EGR which is Exhaust Gas Recirculation.

EGR systems re-breathes the exhaust gases under curtain driving conditions & will make quite a difference to power. If blocked off there will give a power gain

AIS on our XT's or Secondary Air Systems as in the motor car industry are used to get the cartelistic converter to operating temperature as quick as possible & reduces hydrocarbon emissions.

A valve opens which allows fresh air from the filter part of the air box it to enter the exhaust header after the exhaust valve, it adds oxygen to the exhaust gasses coming out of the header, this in turn make the gases super hot which in turn heats up the cats faster which reduces hydrocarbon emissions. The AIS value normally operates according to coolant temperature & works mostly from cold.

http://www.yamaha-motor.ca/technology/technology.php?group=M&tech=AIS

If you are still running Cats I would not recommend that you to disconnect the AIS, your Cat could clog up if you only travel short distances.
Removing the AIS with aftermarket pipes will reduce the popping back sound by 99%. The bike will smell richer as there will be more unburnt fuel exiting the pipes. I have always had mine connected, as when I did the test on the dyno there was no gain having it connected or disconnected.

Some new information has come to hand on the AIS system.

Freez has found by disconnecting the AIS at it's electrical connector & leaving the system unblocked caused the bike to run richer low down on his Dyno.

In my comments on the above thread I tested my bike on the Dyno & crimped the intake hose from the air box to the AIS & it made no difference on the Dyno. Two ways of disconnecting the AIS with 2 different results.

Hi Kev.

Just a correction from my side and apologies if I confused everyone. The reason why the bike was running rich with the AIS's power removed was because it flowed fresh air into the exhaust all the time, making me, or another tuners think the bike is running leaner than it actually was, so we added more fuel to get it to the ratio we normally tune for.

But in fact, that was the incorrect method of doing things, as the AIS was just messing with the A/F ratio readings and did not reflect the true A/F ratio that is supplied to the engine.

You have to block the breather pipe leading to the AIS when you tune this bike, or you will tune wrong.

The AIS by itself, working correctly or disconnected will have no affect on the A/F ratio of the bike.

Only place it can cause a mess with is on the 07 models with the O2 sensors. Unplug the AIS on the 07's and the ECU will think it is running lean and add more fuel and mess up the correct fuelling in the process.

All makes sence, now I can stop thinking. I could not see how it made the fuel mixture richer, but it was making the gas anerlizer think it was lean HHH & so you made the fuel map richer.

Something to remember when making a fuel map for a Power Commander. You can blank off the inlet hose from the airbox to the AIS, but don't just unplug the AIS otherwise your fuel map will be make incorrectly.

Thanks Freez valuable info for the forum members.

outcome ?????
 

Evening All,
So is the final outcome to leave plugged in and all connected as standard, or leave electric plug in but pipe blocked, or pipework normal and electric plug off !!??
I have plug off but pipework untouched at the mo. I felt ( before disconnecting plug) at low revs creeping through traffic you could hear the ais valve opening and closing and this caused a slight surge.

2007, xtx, ackra pipes,

Happy christmas to everyone.:023:

If you are running aftermarket pipes & want to disconnect the AIS leave the electrical connector connected & block off the air intake pipe from the air box to the AIS.

The verdict

There is no gain in power by disconnection the AIS, it may help with poping back of the exhaust on over run when using after market pipes by 99% less poping. It will help with the burning of hydrocarbon emissions if connected. It will effect the results of a fuel map if you are running your bike on a dyno setting up your Air/Fuel ratio & the AIS is just unpluged at the electrical connector & not blocked off at the air intake.

OK, I have now blocked air pipe to ais (from air filter box) and reconnected electrical plug. It dont seem to smell so rich for sure but i feel thou as you let off throttle and the bike is slowing down through engine braking, after about 3 seconds it feels as something changes and all engine braking is lost, and the engine want to run on ???? best noticed at slow speeds in 2nd or 3rd gear. im not sure this is due to the changesof made. ??? anyone elso noticed the running on feeling ? and is there anything to reduce it. Thanks. Happy new year to everyone !!!