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post #11 of 27 (permalink) Old 11-06-2012, 02:35 AM
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Who did you get to do them?
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post #12 of 27 (permalink) Old 11-06-2012, 07:50 AM
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Originally Posted by ThruxtonCafe View Post
Hi All,

I'm new here. I recently bought a new Brooklands Green Thruxton which is still to be delivered. It will be fitted with Triumph TOR exhausts.

Question:
Does anyone know what exactly the air injection system does?
The AI basically introduces a "puff" of air into the exhaust port as the gases are moving into the header. This causes a "secondary" burn to happen within in header pipe. See this link which explains it better.

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post #13 of 27 (permalink) Old 11-06-2012, 07:53 AM
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I can report, after successfully deleting the AI from my otherwise stock 2013 Brooklands Green Thrux, that she runs great with no re-tune. It's an easy mod to do yourself (using the forum for instructions-- those that came with the kit were specific to Carb'ed bikes), and you will learn a lot about your new bike. Go for it!
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post #14 of 27 (permalink) Old 11-06-2012, 08:52 AM
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AI is easy to remove and has no effect on performance. It won't prevent the pipes from turning blue, although it might reduce the rate or extent of it. It also gets the AI junk out of the way of the spark plug.

The OP is in the Netherlands, where the dealer might well not be allowed to remove it, EU rules being what they are.

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post #15 of 27 (permalink) Old 11-06-2012, 09:34 AM
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The concept of AI first began showing up in US cars during the late '60s/early '70s. It may have been used elsewhere before or after, I don't know. US cars often used an AIR (air injection reaction) pump to force fresh air into the exhaust manifold/exhaust port of the head.

The goal was to supply fresh oxygen to the still hot but unburned products of combustion that had failed to completely burn while still in the combustion chamber. With out the AI system, the unburned products of combustion (mostly carbon monoxide and hydrocarbons) would flow through the exhaust system and exit into the air.

Catalytic converters were another way of dealing with some of these problems (albeit by different mechanisms) but were incompatible with the lead used in fuels at the time to improve performance.

The AI system that we have on our bikes is a passive system that uses the drop in pressure at the exhaust port as the exhaust pulse exits the system. A system of check valves allows a small amount of fresh air to be "induced" into the port at the right time to accomplish this purpose.

A side note is that this acts exactly like an exhaust leak at the header joint where the pipe connects to the head. Exhaust leaks, such as this, typically produce popping in the exhaust during overrun. Sound familiar?

The bluing of the header pipes is a result of the additional heat generated by these burning gases, kind of like an after burner. Unfortunately we get no boost in power, just blue pipes.

Art.
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post #16 of 27 (permalink) Old 11-06-2012, 02:52 PM
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For the California boys, a marble is your friend - everything stays on the bike, but your AI troubles go away.
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post #17 of 27 (permalink) Old 11-06-2012, 03:50 PM Thread Starter
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Thanks guys, for all your replies. That answers my questions.

It's now clear how it works and what it causes. I think I´ll just break in the bike first until the first service, and remove the AI myself after a while.

So after removing it, it's not necessary to remap it?

Luc
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post #18 of 27 (permalink) Old 11-06-2012, 04:03 PM
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Quote:
Originally Posted by ThruxtonCafe View Post
Thanks guys, for all your replies. That answers my questions.

It's now clear how it works and what it causes. I think I´ll just break in the bike first until the first service, and remove the AI myself after a while.

So after removing it, it's not necessary to remap it?

Luc
No, it's not. However, do the reset adaption once you remove it.
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post #19 of 27 (permalink) Old 11-06-2012, 08:01 PM
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Quote:
Originally Posted by BirdoPrey View Post
The concept of AI first began showing up in US cars during the late '60s/early '70s. It may have been used elsewhere before or after, I don't know. US cars often used an AIR (air injection reaction) pump to force fresh air into the exhaust manifold/exhaust port of the head.

The goal was to supply fresh oxygen to the still hot but unburned products of combustion that had failed to completely burn while still in the combustion chamber. With out the AI system, the unburned products of combustion (mostly carbon monoxide and hydrocarbons) would flow through the exhaust system and exit into the air.

Catalytic converters were another way of dealing with some of these problems (albeit by different mechanisms) but were incompatible with the lead used in fuels at the time to improve performance.

The AI system that we have on our bikes is a passive system that uses the drop in pressure at the exhaust port as the exhaust pulse exits the system. A system of check valves allows a small amount of fresh air to be "induced" into the port at the right time to accomplish this purpose.

A side note is that this acts exactly like an exhaust leak at the header joint where the pipe connects to the head. Exhaust leaks, such as this, typically produce popping in the exhaust during overrun. Sound familiar?

The bluing of the header pipes is a result of the additional heat generated by these burning gases, kind of like an after burner. Unfortunately we get no boost in power, just blue pipes.

Art.
I have had my Thruxton about 6 months now and the only thing i did from new is put a set of Predator mufflers on it with the arrow 2 into 2 map. I don't have any bluing on the pipes (nothing worth speaking about) and it does not pop on overun at all, ever.
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post #20 of 27 (permalink) Old 11-15-2012, 01:19 PM
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I guess I'm the only one, but I kinda like the bluing.
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