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My Norge is popping on deceleration. I have a mistrel exhaust. Anybody know a good fix?
Hey Pappa Ringo, let's see the girlI just bought an 08 Norge last week...fly and ride from North Dakota...a wonderful 1100 miles
Make sure all exhaust connections are tight and no leaks.
The reason you will get popping on the overrun with standard mapping on W5AM Guzzis, and probably others, is simple.Ignoring facts like cracks in pipes or failed gaskets the system works so that when you go to a negative throttle, (Sub 5* of opening.) with factory mapping no matter what the engine speed the ECU will continue to deliver the correct amount of fuel to maintain idle.Unfortunately, because the engine is pumping harder at higher crank speeds more air gets pushed past the throttle plates so the mixture becomes incombustibly lean but as the engine cycles residual mixture from previous failed cycles will hang around and then every few cycles the mix will become combustible and ignite. When that happens the moment the exhaust valve starts to open the hot gasses exiting the combustion chamber will ignite the previously unburnt charge/s in the exhaust causing the backfiring.With Mark's maps the fuel is cut entirely on a negative throttle until the crank speed drops to less than, (I think, generally.) 2,700 rpm. With no fuel being delivered there is nothing being pumped through the engine to combust either in the combustion chamber or the exhaust pipe. Hence no 'Popping'.This system does mean that there is a slight, but noticeable, increase in engine braking and if one is running down a hill and decelerating on a negative throttle, at 2,700 rpm there is a slight lurch as the fuel kicks back in. It's not intrusive or, in the ordinary course of events, even noticeable. There is a long speed limited hill going into Queanbeyan though that finishes at the beginning of the 60 KPH zone. I often amuse myself by rolling down that hill in sixth gear and trying to judge it so that I get the 'Fuel Lurch' at the same point just before the 60k speed sign. I'm pathetically easily entertained though! When it does cut back in though, depending on temperature and how serious I am about a fully closed throttle, get one small 'Pop' as the fuel cuts back in but only if I'm being a lazy slob and ambient temperature is between about 25-27*C as seen by the dash! Pete