[ridgwayrescue]

'06 1100 Silverado
-Vance & Hines slip-ons with packing removed but baffles still in mufflers.
-stock air intake system

Front sparkplug is reddish/maroon. Back plug is clean/grey.
Exhaust pops/cracks when backing off throttle.

AIS system is unmodified.

Too lean?
Plug the AIS?

Didn't put any StaBil in it last winter. Had a stuck float when I tried to start it this spring. Put Sea Foam in it after I got it started.

 

[Fulltilt1]

Well... From the colors you describe, the front is fuel with some kind of additive, and the rear may be lean. No other work done besides the Slip-ons? I'd seriously consider cleanin the carbs. Have you tried running some SeaFoam cleaner through it?

 

[ridgwayrescue]

Actually yes, the first tank this year had a half can of Sea Foam in it. That may explain the front plug. The more I look at the rear one, it is more brown than I thought. I plugged the short, large diameter hose that is between the AIS filter and the AIS box under the tool storage. It seemed to help a little, but I still think the exhaust is popping too much and more than I remember last year. Since plugging the AIS, it doesn't have the little pops at idle like before.
No other work besides the slip ons.

 

[Fulltilt1]

See that's the problem. Same tank / same fuel should equal same result. I think your aft cylinder carb may have or had the idle circuit partially plugged. Do you have un-tainted fuel in the bike now? If so put in some new plugs and go ride, check the color when you get back. Removing the AIS is a good idea anyway, if its still popping on deceleration there is a possibility that your primary circuit is set a little lean. To correct that you'll need to drill and remove the PMS screw caps for each carb and turn the PMS screw about 1/4-1/2 turn out. PMS (Primary Mixture Screw)

 

[Fulltilt1]

Temporarily disabling the AIS is most easily done at the aft intake manifold. The vacuum line attached there powers the air pump of the AIS. Remove this line and cap the tube on the intake manifold. Use the front manifold as a guide. You can get the rubber caps at Autozone by the PCV valves.

 

[damquick1]

Jerk that Damn AIS system outta there and put it in the trash!

 

[Fulltilt1]

LOL Yeah Mines gone too. Wasn't sure if he wanted his gone yet. I saved my parts so if I failed inspection I could put them back on. Three yrs now I don't think I need it anymore.