There is a
great deal of talk among Star owners about
removal or disabling of the A.I.S.
(Air Induction System). This is an emissions control system that allows
air to be drawn into the exhaust downstream of the cylinder head to ignite
unburnt fuel vapor.
This may cause some popping or backfiring, especially on
deceleration. There is no performance gain to be made from removing
this system; unless you object to the look of the chrome lines or you
are bothered by the popping there is really no reason to remove it.
More importantly, your state vehicle code may require that you need
to leave all emissions controls intact.
I had no
reason to deal with the A.I.S. until I modified my stock exhaust;
with the center baffle removed there was a loud and frequent
backfiring. I decided to disable the system by disconnecting the two
rubber lines connecting the chrome lines and looping them back to
their source (see illustrations below). I then used a golf tee to
plug the small rubber line coming from the rear cylinder intake port.
This disables the system while leaving all of the hardware on the bike.
After leaving the system disabled
months and reading posts on the ISRA
board, I realized that there were several
problems with the process. First, I noticed that there was some
cracking occurring in the rubber lines that I had looped. I heard
accounts of chrome lines rusting through because of moisture
accumulating in them. I checked mine, and sure enough I found water
in each. Last, I discovered raw fuel accumulating in the line that I
had plugged with a golf tee--not a desireable situation. These
symptoms led me to the conclusion that this method of temporarily
disabling the A.I.S. is not safe for the long term; I do not
Since my state does not
test motorcycle emissions systems I elected to remove the system
altogether. I'll not go into the procedure here, as I just followed
the excellent instructions found in a Starcruiser article found here.
I plugged the A.I.S. ports with 10mmx25mm bolts, but there are plugs
available from Pacific
Coast Star and Motorcycle
Enhancements. After removing the system mechanical parts and
lines I also removed the line from the rear cylinder intake port and
capped the nipple with a 3/16" vacuum cap. I saved all parts so
that I could return everything to stock if necessary. The entire
process took me about 45 minutes.