Preview;
I bought my 2011 America used last summer from a dealer. The previous owner had installed the British Customs Air box removal kit and Short slash cut pipes. Previous owner also removed the O2 sensors and installed the plug in resistors to trick the ecm to open loop operation. The air injection (AI) system has not been removed and is completely plugged in and funtional. I verified the TORS map is currently installed with my pc and plug.
My Problem;
Bike runs nicely with great power most of the time. At cold start up with enrichment (choke) on the bike make a rythmic popping and spitting through the carb and out the exhaust. Once warmed up and Choke turned off the rythmic popping and spitting goes away and settles down to a nice smooth idle. Regularly during my ride the bike will pop from the throttle bodies then immediately backfire through the exhaust when slowly opening the throttle. For example, when taking off easy from a stop it will pop/spit from the throttle body then backfire out the exhaust. Sometimes from a stop taking off it will die out which is dangerous in traffic. Another example is when criusing at part throttle then easing in to open throttle I will hear the pop in the throttle body then backfire through the exhaust. Another example when cruising at a constant speed then ease off throttle the quickly back on throttle it will pop then backfire again.
My Theory,
Sounds like a vacuum leak. I have checked the throttle body mounting rubbers and they are tight and not cracked. there are two vacuum lines at each throttle body intake that go to solenoid switches (see pics below). I am not sure what these do so I haven't removed and plugged them to see if this is the source of a suspected vacuum leak. Can I safely disconnect these and see if the bike improves? Are these the last link to the AI system? If so can I remove the AI system with these? I have heard theories the bike runs better (less popping or backfires) with the AI system in place.
Other theories welcome;
What do these symtoms sound like to you?
Thanks in advance for your input.
Rick.
