what is AIS all about????

[dirtysouth]

Posted a thread about popping and got a reply to go to TT store and get AIS kit. Looked through the service manual and could not find any good info on it. Anyone fill me in?

Thanks

[Indy_WR450]

AIS is the plumbing from the exhaust back to the carb to meet Kaliforniastan CARB rules.

Just buy the TT store plugs and eliminate the plumbing.

[byggd]

Posted a thread about popping and got a reply to go to TT store and get AIS kit. Looked through the service manual and could not find any good info on it. Anyone fill me in?

Thanks

AIS = Air Injection System

Might only be on CA bikes?

[RichieGoatGruff]

It put fresh air into the exhaust to dilute it and reduce emissions....basically an EPA-mandated kluge.

[dbailey223]

I think it is all 2005's, not just those in California, byggd

[Summit]

Really, the only thing you need to know aqbout the AIS is .....get rid of it!! Go see your dealer if you have a good one. Yamaha makes a removal kit and jet kit, it's in their race manual. It cost me $100 for both installed and it made a world of difference. Well worth it.

[sandman76513]

AIS = Air Injection System

Might only be on CA bikes?

It is on every 05-06 WR450, not just the models destined for CA. Might even be on the new WR250??

[Rip Wheeler]

AIS or air injection system is a system used to inject air into the exhaust to finish burning any unburnt fuel, thus, reducing hydrocarbons which is unburnt fuel. The air isn't pumped in, but the pulse or low pressure from the exhaust draws it in, this is called the "pulse air" type, otherwise an actual pump would be required. There is a reed valve to keep pressure negative and air only flowing into the exhaust, not the other way. This can make for some nasty backfire on decel, as decel dumps lots of unburnt fuel into the exhaust. The popping is this fuel igniting or burning. In automotive, a "diverter" vale is used to switch air from the exhaust and into the air cleaner on decel to prevent this popping, but I'm sure they didn't want to get too stupid on the WR, just enough garbage to make it Kally green I suspect.

[Matty05]

It is on every 05-06 WR450, not just the models destined for CA. Might even be on the new WR250??

We don't get that crap on our bikes here in Australia.

[jasilva]

We don't get that crap on our bikes here in Australia.

Thats all right then, cheap price to pay not to live in Oz.

Joe

[tp3dxf]

We don't get that crap on our bikes here in Australia.

I bet you will in the next couple of years. Not that I am a fan of it. But Cal seems to set the bar.

[MTRSPORTDAN]

Can I physically see if my bike has this? (plumbing from exhaust to the carb)

[MTRSPORTDAN]

It's a 03 wr450. Sorry

[mousemeat]

Are there performance losses or harmful effects associated with AIS? Or is it just a backfiring thing? Does it make it harder to jet?

If i were to get an '06 and didn't mind the backfiring, could i leave the AIS in without crippling the bike?

[rich1167]

I think it makes it easier to jet and tune the carb due to the fact that all that crap is out of the way. I removed mine and don't regret it. But I have researched the performance issue and found the most popular opinion to be, their is no affect. I can't tell on mine. I have a terrible butt dyno.

[RichieGoatGruff]

Are there performance losses or harmful effects associated with AIS? Or is it just a backfiring thing? Does it make it harder to jet?

If i were to get an '06 and didn't mind the backfiring, could i leave the AIS in without crippling the bike?

No effect on performance....it simply pumps fresh air into the exhaust...prob'ly not even that heavy.