A. There are actually
3 different emissions systems on the Viragos, depending on the year and size.
Below I've listed what is on each model, and where it's located. Disabling the
AIS system on some models seems to stop the incessant back-firing on
deceleration. This does not mean disabling the
"Coasting Enrichener System" on the 1988-on XV750 and XV1100 models.
More Information: The three systems are the above mentioned CES on
the 1988-on XV750 and XV1100 models, The "Mixture Control Valve" on
the 1981-1983 XV750 models and 1985-1985 XV700 models, and the Mixture Control
Valve and Air Induction System on the 1988-on XV750, 1984-on XV1000, and XV1100
models.
The AIS system and MCV systems can safely be disabled by disconnecting the hoses
that go to the valves, and re-routing the vacuum lines to exclude them from the
system. Both of these modifications are effective at reducing and in some cases
eliminating the back-fire that plagues the Viragos on deceleration.
Comments: On the 1981 to 1983 models, the
MCV valve is located on the left front side of the frame under the engine
mounting bracket cover (that cool air-scoop lookin' plastic thingy with the
gaudy amber reflectors on it). On the '84 and '885 XV700, it's located in the
left side pod, or "bug eye" funny looking chrome cover. I have removed
them from both of my bikes, stopping the backfire on both, and the bikes have
suffered no ill effects. For those of you with '86 and newer bikes, your
MCV and AIS are both located in the left pod cover as well. They are easily
disabled, and if you do it, you won't regret it. However...if you live in a
state that insists on making you go through those ridiculous emissions
certification tests, you'll want to leave it intact inside the cover so you can
reconnect it annually for the tests. For those who don't have to have emissions
tested, you can now do away with the left pod entirely, or at the very least gut
the thing and just leave the pod empty.