AIS and Stock Exaust

Hello, I want to remove the AIS as it's just clutter and have a question. I'm not ready to get a Q4 etc. yet and am wondering if removing AIS will make the cat. plug up or cause any other problems with the stock exaust? Thanks -Mike

The AIS is part of the reburn for the exhaust. If you run it long enuf without the AIS your cat will plug up.

All the AIS does is allow negative pressure in the pipe to pull fresh air from the air box under certain conditions (& according to the Yamaha service manual: closed throttle). I would not worry about removing it.

Yamaha tech said that it will plug up the cat as it's part of the cooling system for the exhaust and to NOT remove it unless you have an A/M pipe...

Motorcycles have had air induction since the 1980's when the only cats around were the ones that crapped in a small box on the kitchen floor . Page 7-13 of the WR service manual states:

Quote :

CHECKING THE AIR INDUCTION SYSTEM
Air induction
The air induction system burns unburned exhaust
gases by injecting fresh air (secondary air)
into the exhaust port, reducing the emission of
hydrocarbons. When there is negative pressure
at the exhaust port, the reed valve opens, allowing
secondary air to flow into the exhaust port.
The required temperature for burning the unburned
exhaust gases is approximately 600 to
700
°
C.
Air cut-off valve
The air cut-off valve is controlled by the signals
from the ECU in accordance with the combustion
conditions. Ordinarily, the air cut-off valve
opens to allow the air to flow during idle and
closes to cut-off the flow when the vehicle is being

driven.

I have heard the cat rumor at ADV also & it struck me as odd there as well. The internet is great for spreading information but its spreads all information equally whether founded or not.

This came from a Yamaha tech, not from ADV. I read that in the service manual as well. This was given as a warning, as was mentioning running the bike with an A/M pipe and no tuner; the bike will run VERY lean. What I was told was 'it's a chance you take.'

Shewolf is right kind of
What happens when there are excessive unburned hydrocarbons is the cat will overheat
It can crack, fall apart and block the exhaust
I've never heard of a cat plugging on a bike, I guess it could happen but I doubt the WR is dirty enough to cause a problem
Youd probably have to pour a liter of 2 stroke oil in the tank to make enough pollutants
Taking off the AIS wont do anything for power

I wear the standard exhaust, but I have removed the AIS and the airbox flapper. I thought it was good overall, but I can not understand whether it is good or bad. With these changes can only hope that the R2 would work less "stuffy."
What is the "cat"??
Sorry, I'm starting to make mods, and I do not know if I have started correctly.

Thanks

WRX is right, I was a paid tech for 24 yrs and air induction had been around a long time longer then a cat.. The cat on your bike is fine and will be fine with out AIS.....

WRXer wrote:

Motorcycles have had air induction since the 1980's when the only cats around were the ones that crapped in a small box on the kitchen floor . Page 7-13 of the WR service manual states:

Quote :

CHECKING THE AIR INDUCTION SYSTEM
Air induction
The air induction system burns unburned exhaust
gases by injecting fresh air (secondary air)
into the exhaust port, reducing the emission of
hydrocarbons. When there is negative pressure
at the exhaust port, the reed valve opens, allowing
secondary air to flow into the exhaust port.
The required temperature for burning the unburned
exhaust gases is approximately 600 to
700
°
C.
Air cut-off valve
The air cut-off valve is controlled by the signals
from the ECU in accordance with the combustion
conditions. Ordinarily, the air cut-off valve
opens to allow the air to flow during idle and
closes to cut-off the flow when the vehicle is being

driven.

I have heard the cat rumor at ADV also & it struck me as odd there as well. The internet is great for spreading information but its spreads all information equally whether founded or not.

Thank you very much, I'll understanding.
Maybe "cat" = catalyst ??

Catalytic converter.

I don't want to chance it. I will wait til I get an A/M exhaust before I remove it just to be on the safe side.

I did not know that could be risky to do so before changing the exhaust ... I have to be careful.

Thanks