Popping and Misfiring on Decel

I'm having an annoying little problem of misfiring and occasional popping on deceleration. It doesn't affect performance, or anything, but it is annoying.

I'm took it back to North County house of Motorcycles for this one, since it's been doing it since I got it. When I first got it, the indicated that the bike had been sitting for about a month, so the injectors probably needed to be cleaned out. Well, I've run a whole bottle of injector cleaner through it (1/3 bottle for three tanks) and it's still doing it.

Well, after spending all morning at the dealership, they still don't know why the bike is popping on deceleration. It's not throwing an error code. No warning lights are displayed. According to the bike's ECU, everything is peachy keen.

They're going to have to call Yamaha tomorrow, and see if the corporate tech boys have a clue. So, while they say that something is wrong, they don't know what it might be.

Anybody else run across something like this?

I'm not an expert on the FJR since Ive' only had mine for a couple of months, but it sounds like a similar complaint that VTX owners had. The VTXs with aftermarket exhaust systems would have a lot of "popping" of the exhaust on decel. It was caused by the PAIR system introducing air into the exhaust to clean up unspent exhaust gasses. The sound was already there, but you didn't notice it with the stock mufflers. My VTX did this after I installed V&H Bigshots. There was a procedure to either plug the PAIR system, or to remove it altogether. I did the latter, and the decel popping almost completely went away.

Do you have aftermarket slip- ons, of perhaps a full exhaust system? You will have to wait for the veterans to chime in here, but this might be a place to start.

My first suspicion would be the Air Induction System. Its job is to let air into the exhaust, right at the cylinder head for secondary burn to help meet emissions. The AI system is only supposed to be active when the engine is running the cold enrichment map and after that, only at idle when warmed up. The exhaust popping is a classic sound of air leaking into the exhaust.

The air control solenoid is ON = pass air when there is no 12 volts at the solenoid (the solenoid is normally open), it shuts OFF = no air when there is 12 volts at the solenoid. If there is a plug undone or a wiring problem preventing the solenoid from being powered, it will induct air all the time leading to decel popping all the time.

When your diAG screen is in step 48, toggle the run/stop switch OFF then ON again and it should cause the solenoid to audibly click 5 times if it is working correctly.

Edit: I am agreeing with Bogus, who types faster than I do :lol: The FJR FSM refers to this system as AI System but it is the same thing as PAIR, just named differently from other applications.

Don't take this as gospel but I believe there is an air injector that is an emission device that injects air into the exhaust stream to help burn over rich conditions when on deceleration. If the air injector controller doesn't shut down at the proper time, the extra air can cause the popping sound you describe. Anyone else out there feel free to correct my statements but I think it's something like I described.

Edit: I am agreeing with Bogus, who types faster than I do :lol: The FJR FSM refers to this system as AI System but it is the same thing as PAIR, just named differently from other applications.

I may type faster,(NOT!) but you have explained it better than I could! I knew that the "air injection" system was used to reduce emissions, but not how and when it is activated. We now await advice from the sages on this forum