Motorcycle Club » Star 1100 Classic & Custom

Exhaust Fume Return

4 posts from 3 voices
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  1. pero455

    On The 1100 We Have Those Two Tubes Coming Back From The Exhaust Area To The Cylinders.
    The Question Is: Is It A Burden On The Performance?
    Does It Overheat?
    Is It Better If I Just Plug Them With The Right Size Stainless Plugs?

  2. Ravhite

    Are you referencing the AIS?

  3. pero455

    Those Are Ventilation Hoses.
    Page 44 In The Service Manual.

  4. WhideSdar78

    On The 1100 We Have Those Two Tubes Coming Back...
    This is the AIS. Its purpose is to introduce air into the exhaust system at a port in the cylinder head near where the exhaust pipe attaches. The air introduced into the exhaust will allow any unburnt hydrocarbons in the exhaust to be consumed before they are expelled into the atmosphere. The AIS has NO effect on performance or fuel economy. The tubes do not transport hot gasses so there is no overheating issues. If you switch the stock exhaust for aftermarket slip on mufflers or a full aftermarket exhaust system you will experience a lot of popping and backfiring from the exhaust as long as the AIS is still operating. There are several ways to disable the system but there is no need to unless you have already replaced the exhaust system.
    Here is a link to more info ad also a warning about the AIS and Catalytic Converter equipped 1100s.



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