Triumphrat

Sooty · 08-05-2005

I have now removed the AI system from my T100. I thought from the previous posts I knew how it worked.
I completely dismantled the parts to investigate, Its not an air injector at all, The body contains two reed valves which lets air be drawn from the air box into the exhaust just after the valves. The flow of air is controlled by a valve, this never fully closes and opens more as a vacuum is created by the inlet manifold. The air must be drawn into the exhaust by a vacuum. this must be created by a venturi effect as I always thought the exhaust header would be pressurized by poor flowing silencers. Just shows theres lots to learn and there are lots of very clever people about.

dazco · 08-05-2005

That being the case i wonder why you couldn't disable it just by cutting the 2 hoses and plugging them all?

rick77f · 08-05-2005

You can. It's just nice to get the junk out of the way. Changing spark plugs is easier without it too. On my SV it was much easier to cap off the PAIR valve than try and remove all the stuff. At least on the Triumph the hole can be filled with a 12MMX1.75 bolt of your liking. The Suzuki had a plate and 2 bolts to accomplish the same task.

mac0swaney · 08-05-2005

So...why exactly DO you remove the AI in the first place? Some say it affects performance. Others don't. Some say it affects pipe blueing. Others don't.

Clifford · 08-05-2005

According to studies by people with really big brains and white coats, the AI works by sucking the life out of your Bonnie...

But seriously, it would make sense that the valve would be actuated by the vacuum created after the cylinder has exhausted and the exhaust valve is about to close. At this point in time the exhaust leaving the cylinder would pull the valve open and suck more air in behind it, a tiny puff of which would flow out into the header pipe.

I don't know, I don't design these things, but it seems reasonable, as if it follows the function of the device?

dazco · 08-05-2005

Quote:

So...why exactly DO you remove the AI in the first place? Some say it affects performance. Others don't. Some say it affects pipe blueing. Others don't

All i know is what i read. And from everything i've read it seems unanimous that removal does 2 main things. It eliminates popping, BUT, this only seems to be an issue with those who've done airbox and/or pipe mods. And it eliminates blueing of the header pipes, which only affects bonnies and thruxtons but not americas or speedmasters due to thier double wall pipes. So if you have an america/speedmaster and aren't doing any mods, there should be no need to remove it other than easier spark plug access or if the look of the goodie thats next to the plug bothers you. If you have a bonnie or thruxton and don't like blueing, theres your reason for removing the AI with those. I have a speedmaster and in 1000 miles the double wall pipes have proven that that won't blue, and the bike has never popped. So unless and untill i do any mods i''m leaving it since i've read it has zero effect on performance and is illegal to remove it, even tho you'll never be questioned about it. I also read once that it can add to your gas milage, tho i wouldn't put much stock in something i've only read once. But the rest has been verified by tons of people here and elsewhere.

[ This message was edited by: dazco on 2005-08-05 19:43 ]

Diego · 08-05-2005

> The air must be drawn into the exhaust by a vacuum. this must be created by a venturi effect ...

A reasonable deduction from solid, scientific observation, Sooty! There is a brief impulse of negative pressure after the exhaust stroke is complete.

> mac0swaney asks: So...why exactly DO you remove the AI in the first place? Some say it affects performance. Others don't. Some say it affects pipe blueing. Others don't.

Some people spout just any old BS they've heard someplace or another, mac.

Now, everybody's got a right to their opinions. But not all ideas have equal value! You've got to apply critical thinking skills to sort the real advice from the pseudo-advice that appears in any online forum. One good thing to do is observe over the course of time which people can support their assertions with a logical explanation based on physics and personal experience; versus those who have a short, glib answer, and if questioned, resort to name calling or an appeal to some other Web site that has more agenda to it than solid info.

In this matter, if you'll notice, most people do agree that the AI impacts bluing--but not in all circumstances. Doesn't make a lot of difference on dual-wall pipes, for instance.

As for performance, very few people seriously think that the AI does affect it. There's no data that indicates it does. And if you think about how it works, there's no way that it could.

The air is admitted to the <u>exhaust</u> ports of the engine. It mixes with the exhaust gases to promote afterburning of any fuel vapors that didn't completely burn in the combustion chambers. It's an inexpensive emission control measure with no penalty on performance, and it does significantly reduce the amount of hydrocarbons our inherently dirty engines spew into the air.

CAPTDON · 08-05-2005

DX the A/I The concept is righteous the results minimual
Bonne s are supposed to have Blue pipes 1/4 past the 1st bend Nice shade Purple first Blus 2nd Ans a nice shade od gold (If the mechanic didnt leave handprints) doin the fade The AA/I will keep them bluing Me + 2 friends have same year Bonne s Me & #2 have nicely blues pipes & run super #3 Kept A/i & bafles blued to the mufler Depends what you are into? Capt D

kdrake · 08-05-2005

So, the AI is more or less harmless. How about the crankcase ventilation? Do Bonnevilles push air in and out with every piston stroke? In the old days, hot rodders put a reed valve on the breather to keep from pulling air back in and taking power to do it.

Sooty · 08-06-2005

kdrake, both pistons go up and down together so therefore displace 860cc of air on the down stroke and suck in the same on the upstroke. Because of the volume of the new Bonny crank cases there is not much compression and this is easily vented into the air box with little loss of power.
It was different with the old T140s and Commandos, because of the tight enclosed dry sump cases 750cc of air had to be sucked and blown through a tiny breather pipe each rev, The Commando through a timed breather on the cam shaft. The Triumph would now make the emission people scream, a pipe ran from the engine over the back mudguard and blew oil onto the rear numberplate.