Can AIS Removal Be A Bad Idea??? Ever????

At TT a topic was started about removing the AIS.

It was suggested that removing it, but keeping the stock exhaust, would be a bad idea.

Can this be possible?

Is there any circumstance where removing the AIS crap would be a bad idea for a WR owner????

It was my understanding that the AIS crap was nothing but weight and did nothing for performance or general operation of the motorcycle.

I removed mine and ran the stock exhaust for quite a while before I got the tuner, and it didn't hurt it any. It stopped the popping on decel, I found. All it does is inject air into the exhaust to burn off excess gasses (basically pollution control).

I havent removed mine yet (still have the stock pipe / airbox flapper removed though). My thoughts are that the AIS can only lean the bike out by injecting more air, I have read plenty of people saying the R2 is allready running lean from the factory, so it can only make the bike run richer if anything, I am going to toss mine in a week or 2 when I get round to it.

How can injecting air into the exhaust make a bike run leaner?

Yes, it's pollution control on some level. But the bike is already highly efficient, and sent running lean from the factory from everything I've read.

Most of what I've read from people says that if you tamper with the airbox and open it up, like doing the flapper mod, you are completely safe to remove the AIS system without detriment to the bike at all.

The comment on TT was around the idea that removing the AIS might damage and or destroy the stock exhaust which would then cost money to replace.

How rich would a WR engine have to be running to cause such a build-up of unspent fuel in the exhaust system thereby causing some mini cumbustion/explosion and damaging the stock exhaust?


(and a quick google check for "yamaha ais" yields that there are plenty of Yamaha's that incorporate an AIS system)
(I blame Al Gore )

it doesn't make the bike run leaner,it allows air to be pulled into the exhaust to create a higher temp for a cleaner burn off of pollutants. a "dirty"engines exhaust (dis-abled ais)will make a more sooty type of residue which can lead to clogging up the catalytic converter faster than with a working ais. there is not going to be any unburnt fuel build-up to cause anything other than a sooty/dirty exhaust.

on the lean fuel mapping....i don't think it's as lean as it's been made out to be.i have removed my air flapper and the a.i.s. without using a programer and it runs alot better...and...i definitly have a rich smelling exhaust at idle and also a slightly black sooty exhaust.
getting rid of the ais also stops all that ratty sounding popping and back-firing crap...doing it for this alone is worth it. i actually like the way my stock pipe now sounds.

dirtytrixx400 wrote:

on the lean fuel mapping....i don't think it's as lean as it's been made out to be.i have removed my air flapper and the a.i.s. without using a programer and it runs alot better...and...i definitly have a rich smelling exhaust at idle and also a slightly black sooty exhaust.

Have you pulled your sparkplug and checked it?

motokid wrote:

dirtytrixx400 wrote:

on the lean fuel mapping....i don't think it's as lean as it's been made out to be.i have removed my air flapper and the a.i.s. without using a programer and it runs alot better...and...i definitly have a rich smelling exhaust at idle and also a slightly black sooty exhaust.

Have you pulled your sparkplug and checked it?

no...if it ran worse or anything other than better than the way it was...i would pull it in a second to see what i needed to do.

also,if i had any....any at all....doubts about this being a bad thing to do,i promise i would not post it here or anywhere that it was anything otherwise.

like i was saying...the biggest downfall that i can imagine is clogging up the stock pipes converter faster with the ais removed.
all converters eventually get stopped up.....it's a one way thing with them to begin with.

dirtytrixx400 wrote:

also,if i had any....any at all....doubts about this being a bad thing to do,i promise i would not post it here or anywhere that it was anything otherwise.

like i was saying...the biggest downfall that i can imagine is clogging up the stock pipes converter faster with the ais removed.
all converters eventually get stopped up.....it's a one way thing with them to begin with.

So what's your take on this then?

I'm asking for advice....not questioning your thoughts. (just to be clear)

motokid wrote:

dirtytrixx400 wrote:

also,if i had any....any at all....doubts about this being a bad thing to do,i promise i would not post it here or anywhere that it was anything otherwise.

like i was saying...the biggest downfall that i can imagine is clogging up the stock pipes converter faster with the ais removed.
all converters eventually get stopped up.....it's a one way thing with them to begin with.

So what's your take on this then?

I'm asking for advice....not questioning your thoughts. (just to be clear)

honestly....it looks as near perfect as i could expect it to look.
the white insulator shows the plug is of the right heat range and that it is getting into it's self cleaning temperature range.....the ground electrodes have the right appearance that the fuel/air mixture is good. also the bottom ring(the part the ground electrodes is attached to) usually mirrors the combustion chamber and it too looks good.

plug readings are only a snapshot into whats going on inside your combustion chamber...not the whole story.
everybody is always looking for tan color.......i would be too if it were a 2stroke.

dirtytrixx400 wrote:

getting rid of the ais also stops all that ratty sounding popping and back-firing crap...doing it for this alone is worth it. i actually like the way my stock pipe now sounds.

Have you ever heard a Suzuki LS650/Savage/S40 ? It farts and fires off gunshots in stock tune.

This bike is very quiet in comparison. I'm tempted to leave the intake/exhaust/ECU/EFI alone and just ride the bike as it is, but reading everyone's experiences with their modifications is very interesting

craigq wrote:

dirtytrixx400 wrote:

getting rid of the ais also stops all that ratty sounding popping and back-firing crap...doing it for this alone is worth it. i actually like the way my stock pipe now sounds.

Have you ever heard a Suzuki LS650/Savage/S40 ? It farts and fires off gunshots in stock tune.

This bike is very quiet in comparison. I'm tempted to leave the intake/exhaust/ECU/EFI alone and just ride the bike as it is, but reading everyone's experiences with their modifications is very interesting

yep...lol....i know what your talking about...i had/rode a xt500 for a few years,it was the king of doing that stuff.

Did it sound like this?

http://butifnot.tripod.com/racecar.html

mwakey wrote:

Did it sound like this?

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lmao....thank goodness no

but i had a 90cc yamaha 2stroke when i was a kid sounded real similar

The AIS is necessary for the catalytic convertor. If you change the pipe, you can remove it. By pumping air into the exhaust it not only helps the catalytic convertor burn leftover compounds, but leftover air also dilutes the exhaust, further reducing relative emissions (but not total.)

currently i have the AIS system, but my airbox door is removed...does this present any type of problems?

I have my WRR stock, and I think not removing the airbox flapper helps on keeping the air filter cleaner. I've done many dirt roads trips, with plenty dust, and after cleaning the air filter I was surprised of how clean it was.... just my 2cents!

I too, have removed my air-box lid, still have the AIS in place. It sounds better, and made a noticeable difference to me in smoother acceleration, idling, and power.

In reference to the removal of the air-box lid, not too many rivers and such to worry about over here in Sicilia, but I did lay my bike down in a cold-ass stream in WA.

The AIS (air injection system) is part of a total emissions control system for the WR. It assists the stock exhaust in more effectively reducing unburned gases exiting the exhaust by injecting air into the exhaust pipe or port to continue the burn of any unburned fuel leaving the combustion chamber & by the time it reaches the catalyst in the muffler, there is just a small amount left which the cat will take care of. If the AIS is removed, it leaves all the unburned fuel for the catalyst to try & remove. This makes it build more heat & shortens it's life. I've seen it happen on cars that had injectors stuck open & run rich causing the cat to glow red. It pretty much melts the insides of the cat & then you have a clump of material bouncing around within the shell.

Sorry to revive an old thread but has anyone actually tested the outlet of the AIS??

From what I've seen its just a valve that lets the exhaust suck additional air and not a pump at all.

The standard pipe needs it as many have mention because this unburnt fuel in the exhaust can destroy
the catalytic converter prematurely. That's why all late model bikes and cars have a system like this. It also
has the added bonus of lowering the emissions.

Once you ditch the stock pipe there is no longer any need for the AIS system unless you want your bike to pop and fart on the overrun..lol..

I don't quite understand all these claims of the bike running lean as stock though. The pipe makers test their designs with a STOCK
bike so they aren't going to sell you a pipe without a chip if it was going to blow your bike up. Yes you will get better power with a programmer but that's because of the fuel you can add. And Yamaha isn't going to jet a bike so lean it destroys itself after a simple pipe sway that it knows everyone does anyway. Besides the stock ECU has the facility to cover mild variations in intake and exhaust flow anyway. And if they did run it super lean they wouldn't need to have dreamt up the AIS system in the first place.

Sorry guys just venting as I'm in the process of removing the AIS on my bike when I fit my Yoshi pipe.

Any helpful advise or direction would be handy.

1-I'd like to remove AIS and do flapper mod with stock exhaust-
OKAY?

2-how about removing EXUP and still keep stock exhaust? Okay?

To quote someone much wiser than me:

motokid wrote:

you can remove it - it's not gonna hurt the bike - but why would you? The EXUP increases torque in the lower part of the rpm range. I remember seeing a dyno chart comparison with and without EXUP, there was a noticeable bump somewhere around the 3000 rpm mark I think. Removing it will not increase top end power as the valve is fully open in that position anyway.

The AIS system is intended to work with the Catalytic converter. If provides additional oxygen in the exhaust gas to allow the catalytic converter to burn off any hydrocarbons that may be there.

If you pull the stock muffler and replace it with an aftermarket slip on you have removed the catalytic converter and there is no need for the AIS system and it can be removed. If you do not remove it you may get popping on decel from the additional oxygen lighting off batches of unburnt fuel from time to time.

If you leave the stock muffler in place there is a risk that if you remove the AIS system you could damage the catalytic converter (possibly plug it up) since there is no enough oxygen to complete the combustion process within the catalytic converter.

Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx → xO2 + N2
Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2
Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + [(3x+1)/2]O2 → xCO2 + (x+1)H2O.

https://en.wikipedia.org/wiki/Catalytic_converter