Hey guys. I was just browsing the tech section and saw the article about removing the AIS. What I am wondering is what is the purpose of doing this. Does it increase HP, exhaust volume, etc. I know that getting rid of the "smog pump" on a car helps with power because it is turned by the engine, but does the same apply to our Roadstars? Also, is it worth the trouble to remove it?

Some folks claim it improves performance. More than that, your scoot will stop sounding like a sewing machine. And it cleans up the front end. I doubt it has any performance benefits at all.

Ditto on what MitchellNJ said, no real performance increase but it sure cleans up the left side and front of the bike. Especially when you couple it with the fuel pump removal mod.

Good luck to ya what ever you decide.

Removing it reduced the popping on decel significantly after I swapped to non-OEM pipes. And like it's been said, it cleaned up the front end. Less weight to lug around too.

Remember the cars in the 60's & 70's (80's and some 90's too) that had that extra alternator looking air pump on the engine and the tubes that screwed into the exhaust manifolds? Same thing. The ones on the car were belt driven and ours work by vacuum. It's only purpose is to inject air into the exhaust to make it seem that the emissions are better than they are.

I've been watching these threads about AIS removal for a while now and havn't removed mine. I have an aftermarket exhaust and I can run the RPM's up in any gear including 1st and completly let go of the throttle and it don't pop or backfire. So I figured I didn't need to.
So today I decided to mess with it a little. I unplugged the vac hose coming from the intake and plugged the hose, I took it for a ride to see if that would make any differance in anything. Wow did it. Backfired everytime I let off to shift. And they were loud backfires. So I pulled over and plugged it back in and everything is OK again. So when I got back home I removed and plugged the hoses going into the heads and it was no different then when it was connected. So I'm leaving it alone.

Can someone tell me why mine is like this, and runs fine with AIS connected when so many others have backfiring with aftermarket exhaust and have to disconnect the AIS to get rid of the backfiring?

The only thing I can think of is the intake hose wasn't plugged well enough, allowing air in. That's usually the reason for the popping in your case. Manifold leaks can also cause it, but that isn't what's happening with you.

I guess thet could be it but I had it plugged pretty good (I think) and it was clamped. I'm really curious why I dont have any poping with the AIS hooked up when about everyone else does. I'm talking I can wind it up even in first gear and let completly off and not even a poof let alone a pop or backfire.

You might have the block off plug inside the pump that comes with a lot of the jet kits. This essentially does the same thing as removing it, but just doesn't clean everything up like removing it does. The line going to the intake should still be plugged though.

When I was testing it a couple of years ago I plugged the line with a golf tee and clamped it. Be sure you also plug the two larger hoses at the same time.